Trying to guess thge secret of Rudy Van Gelder while he was creating those classic jazz records, the room canceling mic

At your risk. The CD Blue Train - John Coltrain by the label Blue Note was bought from Monastiraki in Athens. It was played on the Pleiades refference playback system with the 1 transistor per channel 2N3053 power amplifier. Sennheiser hD580 Headphones were also used. It sounded very dry which is a good thing as you cannot hear the recording room and therefore the instruments appear to be played in your listening playback room. Drums sounded to the right side. The impression was that a single mic was used for drums and that this single channel was paned a bit to the right by the mixing desk. The drums were bright and there was no low end emphasis at all. Anyway the impression was that each instrument had its microphone. On headphones it can be felt that when a solo is coming the corresponding channel is faded in. This creates a stereophonic effect for say drums as now there is drums leaking to another mic panned say a bit to the left. But how is this recording so dry? Could it be that Rudy Van gelder u8sed the trick of Lou Burroughs (Electrovoice, descibed in the book Microphones) of the noise canceling microphone? Noise means something you do not want to hear, in this case the room. Could it be that there was a microphone, (omnidirectional?) deliberately connected out of phase in order to cancel the room sound. It could even be a mic used for another instument. It does not matter if it is out of phase the double bass for example would be captured correctly as it is close to its mic. The drums would be captured correctly as they are close to the in phase mic. But this mic would capture ambience. So the out of phase double bass mic. But since one of the mics is out of phase the ambience would cancel when mics are added. Its frequency response would depend on the separation of the 2 mics. Since wavelength increases with lowering of frequency if the mics are quite apart only low frequency ambience is decreased which agrees with the fact that the drums sound so dry at low frequency and the low end is at low volume. Anyway this is a guess. Promissing result was yesteday at Pleiades lab when a 2 female XLR to one male XLR cable made long ago was tried with 2 Electrovoice 635a omni moving coil mics. This cabnle allows them to be connected in parallel, but one female XLR is deliberately connected out of phase. The output side of said cable was connected to Sony TC-D5 Pro in mono mode, monitoring through Sennheiser HD580 geadphones. It was stricking how ouside noise and the room was canceled when the second mic was connected but singing just to one of them. Then one of the mics was fairly close to the Pleyel model 9 piano. If just one mic was used the room gave a horrible sound and some notes where so exagerated by apparently modes of the room (reflection of oposite walls), but when the second further mic (the out of phase one) was conneted, these peaks stoped occuring, and the piano sounded much more pro and like a piano.

Creating loudspeakers with enclosures made of linoleum

At your risk. Please take all safety precausions. 3 Ply glued together 9ike plywood) with PVA glue would give 7.5mm thickness. 45 angles could be cut with an Olfa 45 degree cutter to create a good looking enclosure. A circular hole can be made with an Olfa circular cutter. It may be time comsuming to make. But theoreticaly it can be made on a beach. Linoleum has good vibration absorption qualities. This is easy to verify if one hits it outdoors by hand and compare the sound to the ringing of wood. Even by eye it can be see how quickly the flexing vibration is damped. The plylinoleum could be used for making a baffle speaker. If the one drive unit sounds agreesive it can be tamed with someting like 1mH inductor in series. If treble is lacking then a variable resistor can be connected in parallel with said inductor until the loudspeaker sounds similar to reference headpho0nes such as sennheiser HD580.

A very low noise battery powered electron tube microphone booster preamplifier with no capacitors

At your risk. please take all safety precausions. It should be possible with just 1 direct filament double triode DCC90 (3A5) and just 2 signal transformers, like a langenvin circuit. The electron tubes can be operated with grids at space potential which should be even more low noise. So mic connected to input transformer primary, secondary connected to each control grid. Anodes connected to output transformer primary, center tap connected to Vb or (phantom power 48V which may be too much...). Secondary of output transformer is mic out, center tap could be used to get the phantom power voltage. 2 AAA etc 1.2V batteries in series with fuse and switch to supply firect filament cathodes. This circuit has not been built yet so the negative of va (filament supply) possibly connected to negative of Vb and to chassis. XLR pin 1 connected to its nearby chassis terminal too. If phantom power is not used vb can be made from a few 4LR44 connected in series each pair making roughly one AA battery 9see previous posts). The circuit may even barely operate withy 12v, better with 24V, 36V may start being too much as grids are at space potential and there would be field penetration to grids from the positive anode. This kind of circuit has alreadyt being tried a long time ago with an ECC82 (12AU7) both heater and anodes (plates) supplied with 12V through a protective fuse. It worked but it was very sensitive to light as photons apparently created photoemmision and changed the potential of the grids?. If memery is correct gain would increase with brighter light! The DCC90 would consume much less enery per unit time.

An amazing book featuring EMI Columbia Athens

By Stelios Giannakopoulos who was one of the main sound engineers at EMI Columbia Athens studios. It is his biography but there are so many desxcriptions, references and photos. Stelios even get all the way to london CRL. EMI Central Research Laboratories where Alan Blumlein had been inventing to find more unpublished material, photos, contracts etc. The book is currently only in Hellenic language. There are descriptios of the 3 studios. The title is: O Hxoplasths Stelios Giannakopoulos - Stelios Giannakopoulos, Nikos Pathniwths

Decca EsS/4 speaker mod with Decca ribbon horn loaded tweeter

At your risk. Unfortunately or fortunately the front panel had been driled with many holes where many other fullrange speaker had been mounted in the past, and the back cover removed. It was decided to repare the 10in Celestion woofer and Yiannis did a peferct job with a very complient surround. the bass is so deep it is breathtaking. An inductor of 1.7mh is now connected in series with it and a 1uf to 2.2uF capacitor in series with the large Decca ribbon horn loaded tweeter giver by Mark in London near 2000 AD. The tweeter is mounted on top of the carefully gomme laq revarnish job done before 2000. The tweeter can be moved towards the back until bass source and high sorces are alligned. This is best? done by ear while listening to Lady Lady Lady - Georgio Moroder or Barry Gibd pads or strings on What kind of Fool song with barbara Streisand. It sounds close to Sennheiser HD580 driven from the Pleiades 2n3053 single ended single transistor no negative feedback power amplifier.

A mod for the Roberts RFM3 radio

At your risk. It is adding a series inductor with speaker in order to remover mid and high frequency heaviness. It may be for example 34mH and then 107 Ohm in parallel with said inductor to bring back the high frequency sparckle. Many choices are possible, it can be found by trial and error with an inductor and a resistance box.

A speaker crossover network with just an inductor L

At your risk. This idea came by reading Elements of Sound Recording - Frayne, Wolfe. There is a crossover network with the C in parallel withh woofer, L in parallel with tweeter and the 2 drive units are in series. So what if we remove the capacitor. It works! Only the tweeter has an inductor in parallel to it. But it is very tricky as one might need a higher L for the woofer and lower L for the tweeter. Maybe using a tapped inductor, ie an autotransformer could solve the problem, not tried yet. Anyway it sounded quite good with a Philips woofer and a japanese paper tweeter. Actualy it was the first time it was realised that the song What kind of Fool - Streisand, Gibb begins with his (Barry) and her (Barbara) breath in sequence. So far in my humble opinion an 1.7mH inductor in series with woofer and 500nf in series with say 20ohms in with tweeter sound closer to Sennheiser HD580m reference headphones. Driving amplifier is Pleiades 2N3053 with just one transistor in class A of cource and no negative feedback.

Today is it global Solar Water Heater day?

Loudness, Its Definition, Measurment, and Calculation - Harvey Fletcher and W.A.Munson, Bell TelephoneLlaboratories - JASA October 1933

At your risk. The amazing paper publised nearly 100 years ago showing that loudness does not depend only on intensity but frequency, waveform, psychological state of listener etc. my humble observation while reading this paper is that while +70dB intensity compared to threshold at 1KHz can still not be heard by a human it may have dramatic psychological effect to a human being if coming say from machinery in the same building (structure born sound) for prolonged periods, (for example in the house you live in, try to sleep etc). After all sub or very low frequency audio is used in thriller movies. So local authaurities must take into account, a law on moise protection should take all these into account. If there is not data available then research is needed.

Creating baffle speaker as solar panel to drive the amplifier

At your risk. For example the solar panel serving as a speaker baffle at the same time, which a suitable hole to mount the speaker.

On creating a great sounding speaker with the Fostex FE-127E fullrange speaker or other good quality fullrange speakers or a good quality woofer, tweeter combination

At your risk. See next posts.

Creating speaker baffle from cardboards glued together to increase thickness

At your risk. A 4mm baffle was created by glueing 2 layers of 2mm by PVA water soluble glue. Size of panel is 50cm by 70cm. Promissing sound. More thickness, say 3 ply increases bass as a thicker matterial insulates more the bass. But for some reason 4 ply sounded a bit bass heavy on particular 50cm by 70cm baffle and speaker. Bass and treble response should be balanced on any speaker as we know from Olson's RCA research on the influence on bandwidth to a natural sound. For example if a speaker reproduces from 100Hz up it will sound shriil if it goes up to 20kHz. After all 40Hz is ones octave above 20Hz, 10KHz is one octave below 20kHz. Currentlty on Pleiades lab comparisons are done by ear-brain speaker vs reference Sennheiser hd-580 headphones at same loudness. There was not much bass with Tesla 5in speaker although the mid quality was good. There was some bass with the Fostex speaker. there was much more beautifull and deep bass with the Grundig 5"x10'fullrange speaker. Mid high heaviness was reduced by adding a sereis inductor of 1.7mH see next posts. How would baffles created from 2 or 3 linoleum boards glued together would sound like? How would a say Puioneer CS-353 size box made from such thickness linoleum panels sound like with the great Fostex 4.5'FE-127E connected in series with a 1.7mH inductor and 40 ohms in parallel with such inductorm (see next posts) sound like? The idea is to use the sound absorption (damping) properties of linoleum while creating something colored and beautiful. 45 degrees panels may be cut very carefully with the Olfa 45 degrees cutter, not tried yet.

The Zeis Ikon typ:31-06 51cm by 51cm baffle full range 7" cabin speaker sounds great with a 1.07mH to 1.7mH inductor in series

At your risk. Mid high heaviness is gone. A high say 47ohms or greater resistor can be connected in parallel with said inductor if some increase of high frequency response is needed. Promising results.

On calibrating home made speakers by ear using SennheiserHD-580 open back headphones as reference

At your risk. This is how it is currently done on Pleiades lab. In real time under real room listening environment. A good CD such as Guilty - Steisand, Gibb is on Sony CD Walkman. Its line out is connected to class A Pleides 2N3053 power amplifier feeding speaker to be acousticaly calibrated. Phones out is connected to excellent neutral Sennheiser HD580 headphones. Volume is adjusted so that headphones, or speaker sounds equally loud so that the listener's brain is on the same equal loudness curve (Fletcher-Munson curves). Say a Philips 8in woofer is placd on a 21cm by 29cm by 48cm Pioneer CS-353 box (actually this box may be small). If it is directly connected to amplifier it sounds mid and midhigh heavy. If a 1.07mH inductor is placed in series the midhigh heaviness is gone and the bass can now be clear. Say then a paper cone tweeter is connected by a series 2.2uF capacitor. We get the treble but it sounds a bit strange. Pressing pause on CD Walkmann, the power is disconected from power amp and the headphones are worn. Now Barbara Streisand voice sounds much more warm with less high frequency heaviness on the song A Woman in Love. Goinjg back to speaker mode, a variable series resistor is connected in series with capacitor and tweeter to control amount of high frequency content until Barbara sounds as equal as possible to Barbara on the reference headphones HD-580. When her voice sounds right the resistance can be measured to be say 20 ohms in this particular case. By still comparing speaker and headphones in turn it is found that there is still a mid high heaviness. Capacitor is now changed to 0.5uf which makes sencs as the high series resistance increases the time constant which is RC ie resistance times capacitance. Now it sound much closer to reference headphones and there is a smile in your face as you look at the blue sky. But there is still some midbass heaviness. It is decided to increase the woofer series connecetd inductance by inserting a screwdriver inside the bobbin core of said inductor. Now it sounds almost perfect and you laugh. The inductor is later measured on an impedance bridge to be 1.7mH. Same tactic can be used to remove midhigh heaviness from fullrange speakers, the capacitor usually is not needed but the inductor and a resistor in parallel with it is needed, see next post. So the most expensive apparatous is used to full advantage, your ears and your brain.

On placing fullrange baffle or non baffle (even closed box) spakers to the place they trully deserve

At your risk. They sound amazing due to their point source coherence etc but usually there is an annoying mid high heaviness that can hurt. So this is an option. Adding an say 1.7mH inductor in series to cut mid, midhigh heaviness, ie treeting it like a woofer. Then to restore high frequencies a resitor of say 29ohms is placed in parallel with said inductor. the resistor can be variable until one gets it right. Results are promising. These are values used with the great Fostex FE-127E 4.5ii fullrange placed on a Pioneer cs-353 box. Unboomy deep articulate bass, natural mid, sweet highs. It works nicely with other great full range speakers such as a 5ii by 10ii Grundig on baffle etc. Tried also sussesfully with a Staren 5ii fullrange and a Bayma 8ii fullrange. If a woofer such as a Philips 8in is used it may be preferable to uise a small say 1uF capacitor instead of said resistor in order to enchance high frequency response, ie treat the speaker as both a woofer and a tweeter!, see a previous post on speakers with or without baffle.

Is the Pleiades linoleum Auratone type C a failure?

At your risk. Possibly. It turns out the Tesla fullrage speaker used has very little bass, ie high reasonant frequency. But it can be greatly improved by adding in series an inductance of 24mH to remove mid, mid high heaviness, and say 50ohms in parallel with said inductance in order to remove resultant prominance in bass ie add back the sparcle. Fed by the Pleiades 2n3053 class A amplifier when at a high volume setting the non linear distortion on voices, Barbara Streisamd, Bary Gibb is very interesting, on the song What Kind of Fool.

Unexpected nice distortion on Pleiades 2 K117 microphone preamplifier by chance

At your risk! While fine tuning the second stage... The coupling capacitor from 1st amplifying stage was disconnected to 2nd stage and music from the Sony Cd walkman was connected to potentiometer feeding second stage on the small made in Taiwan breadboar At a point Vb 9V batterysupply was disconnected from output transformer and was connected by mistake to one rail below feeding only the onlder version drain resisator of 22Kohms. surprisingly music could be heared on headphones connected to output transformer with a very interesting distortion on Barbara Streisand vocals. And no matter how loud distortion did not become ugly. By observing carefully the schematic the output transformer is still connected to the drain of output stage but its other side is connected to the upper side of the 1rst stage drain resistor. So effectively this other side of the transformer is connected to ground through the whole 1st JFEt stage. It worked only with high values of 2nd stage source resistor, say 3.8Kohms.

Updates on the Pleiades 2 K117 (2 jfet only) no feedback low noise microphone preamplifier with balanced input and output, 9 volt battery supply

At your risk. It can directly drive 300 ohm Sennheiser headphones by being fed with a shure SM58 microphone from a soft singing voice 24in from microphone. The schematic is as simple as it may get, input transformer, K117 resistance capacitance coupled stage in class A, attenuating potentiometer, K117 transformer coupled output stage! The gain is dramaticaly inscreased by changing the second stage source (bias( resistor to 420 ohms thereby increasing output stage power. 2 tiny (input and output) transformers are used which have a low inductance typicaly 100mH to 4H to cut bass heaviness to listener brain when a flat mic is used in order to compensated for equal loudness curves, voice effort curves. In detail component values, schematic: Mic input transformer: Thordarson MIT 209. 68nF coupling capacitor to gate. !Mohm gate resistor to ground. K117 JFEt. 100Kohm drain resistor (electron tube similarity for high gain , small device current can give very low noise). 10Kohm source bias resistor in parallel with 47uF/35V electrolytic capacitor. 470nF coupling capacitor from drain to 220Kohm log potentiometer. Other side of pot to ground, tap of pot to 2nd k117 JFET gate. 1 Mohm resistor from gate to ground. 420ohm resistor from source to ground for self bias, in parallel with 47uF/35V electrolytic capacitor. UTC DO-T9 output capacitor directly connected to drain as on class A single ended power amplifiers. That's all folks! It is intended to be placed insisde a beautiful looking beige-brown Retex made in Spain console box with a bulgin 9 volt battery holder.

amazing biography of inventor Edisson

At your risk. It is like watching a movie, thrilling, why not a movie? The book is Thomas Alba Edisson - Glenwood Clark Edisson attended only 3 months of school as the teacher and inspector insulted him, so he was taught at home by his mother who was a teacher. His father would give him 25c for every book he read. Edisson tought himself, started doing experiments many times until he was convinced that a theory is good or not! For his inventions he worked very hard doing so many experiments until he got it as he wished.

The Shure SM7b has a tiny transformer inside the capsule

At your risk. Older posts stating that SM7 does not have a transformer are most likely wrong, Theodoris who had the chance to open up a defective capsule said he had found a tiny transformer inside it. So it at the secondary of this transformer that we have 150 ohms output impedance.

Testing Electro-Voice 664 variable D moving coil microphone with Pleiades 2 k117 preamplifier old version

At your risk. The older 2 k117 version has a lower load resistor on first stage than 100K, no potentiometr between the 2 stages, a lower load resistor on second stage, so gain is lower. The mic tested is new old stock bought from Yiannis who supplied these in the 60's to the military television. At that time the goverrment in Greece was miliotary so was the TV station. From the mics tested they liked most the 664. The particular mic not sold to them is s/n 164995. After a new flexible Eurocable of blue color was soldered to the Amphenol connector at the low impedance terminals, the mic sings, amazing sound and detail. Tested at singing male voice 24in from nose, about 30 degrees towards head from above.

Increasing the gain of Pleiades 2 K117 microphone preamplifier part 2

At your risk. A tiny output transformer had been used on part 1. A much larger Belclere output transformer was tried, somehow more clear sound. Then a 220K potentiometer was connected between stage 1 and 2. It works great, very low noise, gain of preamplifier can now be adjusted. So it is certainly possible with just one input transformer, 2 JFets, one output transformer, no negative feedback, to go from dynamic microphone level to line level, feeding Sennheiser HD580 headphones for example. Battery supply is an ordinary 9V battery which should last long time.

Listening to Guilty - Barabara streisand, Barry Gibb CD on the Pleiades 2n3053 single transistor per channel power amplifier in class A with no feedback

At your risk. Today Eleni from the excellent Record shop Record House handed me the anticipated CD. The amplifier is in more detail described on older posts. The output transformers are the hand made ones wound on small Siemens ferrite E inverted E cores with air gap added. Frequency respone which number of turns described on previous posts is flat 40hz to 40KHz with no negative feedback of cource. The sound quality is amazing. Breathtaking, promising. deep but not boomy bass, smooth mid and amazing extended treble whith no harshness, with sweetness and cymbals appearing to be real ones inside the room. Barbara and Barry in breath taking peformance. Signal path, cD - Sony CD Walkan line out - Pleiades 2N3053 2 channels - Celestion Ditton 150 at 2 m in a small bedroo with 3 differenct size panel low frequency absorbers. The big panel is behing the speakers away from the wall, its upper side only touching it and its lower side touching the wooden floor. panel in landscape orientation. Panels made of drawing frames with canvas with betumin roofing felt panel fed at the back side of them. Linoleum must be more suitable for enviromntal and cleaner air of room condition.

Increqsing the gain of the Pleiades 2 K117 microphone preamplifier

At your risk.It is a 2 JFET microphone preamplifier, mic feeding the input transformer and 2nd JFet feeding the output transformer which feeds for example the Sennheiser Hd580 headphones. Vb has been changed to a 9 Volt battery. Load resistor of first stage has been changed to 100Kohm, and of 2nd stage to 22Kohm. Now gain is very high and the 2nd stage clips. There is again FM radio reception, floating wire picking up RF etc. Maby a potentiometer should be connected between the 2 stages to attenuate what the 2nd JFET gets from the 1st. Also to check if the whole thing does not oscillate.

Shure SM7 internal switchable filters

By looking at the datasheet of the SM7 it makes sense that when the single 240mH inductor is connected, there is low cut. And when the other filter of 11mH in series with 220nF is connected the high frequency response is flat. When no filter is connected the capsule, similaer to SM57, or SM58 manifests its presence peak that the inventor Ernie Seeler did not like. Would an SM58 sound very similar to SM7 if similar band arrenuate filter is used, and similar high pass filter is used?. Attention should be made to the fact that the impedance of the SM7 is 150 ohms whereas of the SM58 is 300ohms or perhaps more. Also one must take into account that rea; inductors have series resistance which is a good thing for example making the slope of the hi pass gentler, and the Q of the resonant filter lower increasing the bandwidth of the band reject filter and arranging the maximum reduction of the peak to be such that a flat frequency responce is obtained. Would it be possible to use variable series resistors for that purpose? The SM7 seems to be a very good microphone if Michael Jackson, Whitney Houston were cutting vocals in the studio with it.

There are mistakes on the constant k, T, PI filters which are now corrected on the previous posts

At your risk. Please also note that these filters have by definition the useful property that ZL times ZC equals R times R for any frequency. (the impedance of an inductance L is 2 times PI time L, the impedance of a capacitance C is 1 over (2 times Pi times C). It would be interesting to use as image impedance the output impedance of a Shure SM58, eg R+320 ohms and calculate suitable imductors, capacitors for various high pass cut of frequencies, or even a band reject filter of say 5Khz to convert the peak to flat as is done of the SM7 microphone?

An amazing book on perfecting eyesight without glasses

At your risk. It is fascinating , The Bates method for BETTER EYESIGHT WITHOUT GLASSES - W. H. Bates, MD A very inteligent doctor. shakes older theories like Einstein did. In fact the most recent Pleiades filter of 155mH was assembled without using a magnifying glass. Winding was done months ago using a magnifying glass. Diameter of wire is 0.08mm. Number of turnes 261. Siemens Epcos toroid assembled inside Neutrik modules to create a nice looking XLR female to male inline filter. It sounds nice at 24in from mic, mic above head towards nose.

An attempt to remove excess mid high frequency content from SM58

At your risk. Trying to figure out how the beautiful vocal sound of Lady Lady - Morroder may be made. Mic distance used on this experiment is 24in, 30 degrees towards nose above head. A Pleiades inline low cut filter of 155mH was connected to mic. Then to reduce mids a filter like the one inside SM7 was made with 11mH, 220uF in serries and the total connected again across source. In fact mic initialy was not connected, the line out of Sony CD walkman was connected having an output impedance of 300Ohms on a vocal recording that was not good, too mid heavy. Then the Pleiades 2n3053 power amp was driving the Celestion Ditton 150 speaker. The filter worked and by using a capacitor box 100nF was found to sound more proffesional than 220nF on this particular male vocal case. If wa calculates the resonance frequency by equating the inductor reactance to capacitor reactance ie wL=1/wC, where w(omega) is angular frequency or velocity of the rotating vector that produces a sinewave on its projection to the sin axis of a trigonometric circle, w=2 times PI=3.14 times frequency. A trigonomatric circle is defined a circle with radius 1. For C=220nf we get rougghly 3.5KHz, for C=100nF we get roughly 5KHz which seems consistent with the inherent peak of SM58 that i wish to reduce in hope that the higher frequencies would shine even better. A resistor in series might be needed too to adjust the notch filter bandwidth. Initial listening tests with SM58 at very low volume are promising. Low volume with just 2 JFets driving the HD580 headphones (Pleiades 2 K117) pre amplifier directly driven from mic trough a Canford inline input transformer. All filters connected just after mic, before the input transformer.

Equations for constant k high pass filters

At your risk. They are given on previous post with title: Shure SM58 connected to Pleiades (175mH:175mH) or EMI RS106A part 2 An important term is image impedance, see references on previous post. According to the book:Elements of Sound Recording - Frayne, Wolfe the T network should be 2C capacitor on left side, inductor L to ground, capacitor 2C on the right side. Network Pi should be on left side inductor L/2 to ground, Capacitor C on top sending music signal to the right inductor L/2 whose bottom side is connected to ground.

Rememering all the good things only creates much hapiness

Pleiades Crossover finetuning with a variable inductor

At your risl. As on previous posts, an inductor in parallel with a capacitor is in series between amplifier and woofer-fullrange drive unit which is hung on air without baffle. The inductaor takes away the mid heaviness leaving the bass and the capacitor supplies the high frequency music content. Music source is Careless Whisper - Wham from Wham's last CD. The Sony Walkman has two outputs one for headphones where Sennheiser HD580 are connected for reference and direct comparison. Second output is line output where Pleiades 2N3053 single transistor class A power amplifier with output transformer and no negative feedback is connected feeding the Pleiades crossover. The air core inductor is 1.07mH. Capacistor from yesterday's listening tests directly comparing with HD580 changed to 1 microfarad. and results were impressive, sound closer to HD580 than other cabinet speakers in Pleiades lab as they sounded more bass and treble heavy than HD580. That there was still a bit mid heaviness. Remembering Mr. Yiannis from Elina, his crossover with iron screw inside by accident, it was decided to gradualy insert a screwdriver inside the air core inductor in order to make it a variable inductor , increasing inductance to cut more mids, while listening in real time! It worked remarkable well. George Michael's voice sounds as natural, very close to HD580. Inductance measured by the bridge is 1.7 Henries. Actually it just happened that the air core hole is facing the ceiling and the screw driver is inserted until the floor were the air core stands, so the screwdriver stands supported by the air core.

The magical power of the Universe

Quoted by Natalie.

TubeTrap patents by Arthur M. Noxon

At your risk. Please take all safety precautions as on all euroelectron posts. There are many patents, i think this is the one I had read, US4,548,292. Limp mass membrane absorber is also used, see also: https://www.acousticsciences.com/artblog/limp-mass-membrane-bass-traps/ i may be wrong but i get the impression that what Sean Davies had told me on using betumin roofing felt or linoleum panels are mentioned on Gilford's BBC Acoustics book may be different. Linoleum or roofing felt dissipates low frequency energy by bending itself thereby converting vibration to heat by the hysteriis loop of the material. But porous absorbers are added to these for extra damping. Art Norton discusses on his blog (above link) that the resistive (disipative) part is the porous material. But if i am not wrong the vinyl sheet on the TubeTrap may be doing heat dissipation by deflection too. How would TubeTraps absorb using linoleum, perforated linoleum? Or perhaps could Pleiades absorbers be made by twisting linoleum so that it becomes a cylinder and then let it stand on floor or hung from ceiling, linoleum wouild absorb bass by deflection, and would provide dispersion by sound waves of other frequency hit its cylindrical surface. Would porous absorber be needed inside? Hiting this material gives a well damped sound.

Reading agian after many years that Michael Jackson was recording vocals surrounded by Acoustic Sciences Corporation TubeTraps...

placed by Bruce Swedien, invented by Art Noton. This is a page of articles by Art Noton: https://www.tubetrap.com/tubetrap-art-noxon.htm i remember the patent document had also been found on espacenet.

Shure SM58 connected to Pleiades (175mH:175mH) or EMI RS106A part 2

At your risk. The Pleiades high pass filter, transformer in this case, has a slope of 6db per octave as it is 1st order (only inductance). The EMI RS106A should have a slope of 12dB per octave as it is 2nd order, C in series, L shunt, C in series, ie a T network. This explains why it sounds less dense at 150Hz cutoff setting. It sounded also very nice at 300Hz setting when mic was at 12in or 9in distance from nose. There is some buzz maybe because the filter in unbalanced or because the ground terminals at the back barrier strip are not properly set. There is no buzz or hum on the Pleiades filter as it is balanced, in fact a bifilar input transformer. A low inducatnce Pleiades filter, just an inductor of say 150mH may be tried for a less dense vocal. It may also be a good idea to create a Pleiades filter of 2nd order T network or O network for balanced. Equations for constant k filters (constant image impedance) may be used, is this what the EMI engineers or Rupert Neve did for his eqs? If memory is corrent there are also some filters called m derived. Details for all those could be found in the book Cinema Engineering, or the book Elements of sound Recording - Frayne, Wolfe. There is also a nomograph by Seito Yamasita in Radio and Television News - Aug - 1952. The equations given if R is the image impedance and fo the cutoff frequency: L=R/4PIfo (we take R, devide by 4, devide by 3.14, devide by fo), C=1/4PIfoR. where PI approximation is 3.14, Pythagoras constant. Then the T network is C/2 in series, L shunt, C/2 in series or i guess the H balanced version should have C, C on the left side, C,C on the right side. The PI version given on the article has L/2 on the left side shunt, C in series, L/2 shunt on the right side, the O balanced version i guess should be similar for inductors but 2C on top and 2C on the bottom. According to the book:Elements of Sound Recording - Frayne, Wolfe the T network should be 2C capacitor on left side, inductor L to ground, capacitor 2C on the right side. Network Pi should be on left side inductor L/2 to ground, Capacitor C on top sending music signal to the right inductor L/2 whose bottom side is connected to ground.

Shure SM58 connected to Pleiades (175mH:175mH) or EMIRS106A for hi pass filtering

Male voice singing softly No Surprises - Radiohead 24in from SM58, mic 30 degrees towards nose above head. After filtering connecting to the mic input of Sony TC-D5M. At the 150Hz setting EMI 106A sounded fantastic, less fat than with the Pleiades 175mH:175mH which may be better together with other instruments in a mix? But then listening again to Radiohead there seemed to be some more bass in the voice. Monitoring was with Pleiades 2N3053 class A amplifier connected to Celestion Ditton 150.

The Pleiades Crossover, Inductor value bridge measurment

At your risk. The Pleiades crossover is an inductor in parallel with a capacitor between amplifier and single speaker drive unit. Its purpose is to equalize the single drive unit (a woofer or a woofer fulltange) in order that it sounds correct without the addition of any other drive unit, without a cabinet, without even a baffle, just the drive unit hung on air. See previous posts. The first experiment had an inductor of 0.9mH, Q=0.8 and a 2.2uF capacitor. Since Big in Japan - Alphaville was unsed for the listening tests with the Pleiades 2N3053 single transistor class A power amplifier and there was still some midrange empphasis on the singer voice even after adding the capacitor, L was increased to 2mH with better results resembling listening to the sennheiser Hd580 headphones with a bit less bass of course since there is no baffle or cabinet. Other nice combination is 3mH and 1mF which sounded nice on Careless Whisper - George Michael. other nice combination used today is 1.07mH (Q=3) air inductor (previous experiment was with iron core transformer like inductor) and 1uF MKT Philips orange capacitor as on previous experiments. Obviously measurments should be made on anechoic or open air enivirinment.

DL93 must be replaced by DL94 on previous post

At your risk. It is a typo but the same schematic can be used for all sort of different electron tubes. EL94 is also a possibility as the input transformer can bring the volatge up to the same level (say 4V) as needed by DL type electron tubes. In fact the schematic is very similar to the Pleiades V6 battery powered electron tube low noise mic booster. The only difference is that the power amplifier does not need the high Megohm contact potential compensating resistor from anode to control grid (Pleiades bias) that makes the mic booster amplifier operate at say 4V at the anode only. When the context is electron tubes by contact potential we mean the potential created by the electron cloud boiling electrons that makes it difficult for new electrons to escape cathode (when the anode potential is low). When the anode potential is high there is electric field penetration which reduces the negative potential at grid from the electron cloud. But a power amplifier as opposed to a very low noise pre preamplifier, needs higher powe,r hence the high anode voltage together with negative bias in order to keep the anode current reasonably low in order not to destoy the electron type. (The inventor of what is called here Pleiades bias seems to be the inventor of battery powered electron tube guitar pedals, see older posts). Anyway everything in euroelectron is open source, free to use provided other party rights are not infringed.

eureka!, How to Make a (Speaker) drive unit Sound Good Without a Baffle or Enclosure

At your risk. Please take all safety precautions including protecting your precious ears. If a woofer with lightweight paper cone is held by hand and fed by a good quality very low power (protecting our ears) class A amplifier with no negative feedback through an inductor (inductor in series), the sound is surprisingly nice. There is somehow deep bass and the midrange nastyness is missing as the inductor lets the bass in and cuts everything else at a gentle slope of 6dB per octave. But treble is missing. But is the same speaker is disconeected from woofer out of the crossover network just used and connected to tweeter out the treble is very nice without the razor cutting edge of using a tweeter on its own. If said speaker is connected directly to said amplifier only mid nastiness is heard which covers in our perception both bass and treble. So said speaker is connected back to woofer out ie inductor in series. And then.... a capacitor of say 2.2 uF feeds it simultaneously from the amplifier! So we get trable too, the bass we had before and the mid nastiness missing. In fact the balace by chance was almost right the reduced mid blended well with bass and treble. And according to the experiment by Olson of RCA perhaps as many octaves were missing from bass and treble part of the human hearing spectrum creating a balanced sound. Since we have a single speker point source there were no phase errors and since no box there is no colorations. And according to speaking with Costas at Praxis studio hearing mid detail is important in creating or checking a mix, hence the Auratone speaker. But perhaps this is simpler and sounds better. The inductor has not been measured yet. The speaker used is printed at the magnet back: 00 80400/W4, 2422 257 28204, made in Belgium, DD 00 543 5. Signal path Italian 60's songs compack disc club compilation or Careless Wisper - George Michael on CD - Pleiades 2N3053 single transistor power amplifier in class A - said speaker. So the nice little trick is feeding the no baffle air hung drive unit with a parallel combination of inductor and capacitor in order to create a gentle slope low frequency (bass) high frequency (treble) pass filter or a gentle slope mid frequency regect filter. Obviously it cannot be used at high intensity (power) as the cone ir unloaded but it sounds loud if used at smaller distance and the most important is protecting our ears from high intensity.

Stars - Dubstar

It was played at AB supermarket. They were very kind at headquarters to inform the title and artist of this nice song.

Using a MOSFET on these single transistor Pleiades powwer amplifiers?

At your risk. Please take all safety precautions. It looks tricky as by looking at some datasheets the on channel resistance is a fraction for an ohm. Typical current is a few amps. So it seems a step up output transformer is needed with a step up input transformer. Another option since depletion FETS do not need a say +4V at gate to turn on, is to use JFETS such as 2N3819. Many in parallel.

Increasing the power of the single transistor Pleiades BD139 amplifier at 12V only

At your risk. Please take all safety precautions. A multy turn ratio output transformer (it must be air gaped but so far tests have been donbe without introducinbg air gap) was created with secondary 9speaker side) inductance of about 40mH. Various collector volatges were tried including 12v, 24V, 36V, 48V. 24V sounded very nice, see also the Pleiades 2N3053 amplifier. The BD139 due to higher hFE is more sensitive needing less bias current and less music input voltage. Using the 5:1 ratio at Vb=12V requires about 27mA collector current for great class A operation (electrons flowing all time) sound. Rb=71Kohms. It sounds loud and clear. The schematic is just a single transistor with air gaped output transformer in the collector circuit, and just a bias resistor from collector to Base. The 2N3055 (not to be confused with 2N3053) sounded briliant as all the other mentioned transistors but it seems even more sensistive than 2N3053 and even BD139. But it blocked at Vb=48V for no reason known to me. It sung at Vb=24V. Higher Vb was tried with higher transformer ratios eg 7:1, 10:1, 13:1, 17:1. The laminations used were EI grand orient by Tranceria Ligure bought from Stefos in Athens.

How does the Pleiades DL93 single electron tube, 2 transformers and no other component audio power amplifier in class A schematic look like

At your risk. Please take all safety precautions. It looks very much like figures of patent US1349252A, Method of and Means for Utilizing thernionic currents - Harold D Harold.

Recording as many needed parts on the same analog magnetic recording track without generation loss

At your risk. See also a previous post. This is how Mike Oldfield created his Tubullar Bells demo by covering the erase head. Anyway at Pleiades lab the erase head of a Tascam Porta 03 cassette recorder has been disconected. Many singing parts were recorded on top of each other using just an SM58 at 24in above head connected to a Pleiades 175mH high pass filter. It is like painting on the same paper with different crayons. The 2nd pass partially blurs (only the very high frequencies are more affected) the 1st. The 3rd pass partrially blurs the 2nd and 1st. But the 4th, 5th,..., pass does not affect the 1st! For example a male singing voice immitated singing ducks of different age. Then the casstte recording of about 10 ducks in choir concert was played to Vicky's hi-fi system and she thought the recording had been done in a commercial good quality recording studio.

At the most unlikely places extraordinary things can be found

For example the Restaurant Samos by Olga and Fotis on Liosion street.

There is a great article on Glass Audio called try Battery Tubes - Larry Lisle

Thank a lot Larry Lisle for inspiration. This artcle was possibly handed to me by someone who was working at an electronics lab at the Airport of Ellinikon when doing my military service and a good officer who apreciated my grandfather George sent me to the music department of the Airforce. We were discussing with this technician the 1H4 triode.

My grandfathers, grandmothers

From my mother side, Manolis born in Crete, singing till late age on Church. Eleni from Prusa, sweet voice. From my father side, George from Smyrni, played a bit a stringed instrument, had to move to Athens and then went to US for many years then came back to Athens. Maritsa from Prusa, played a bit the violin. My great grand father from my mother side, Menelaos, gifted me a real piano. He enjoyed listening as well as my other grandfathers when i was a kid my first single ended transistor amplifier with tiny output transformer connected to some Sony low impedance headphones (attention protect yur hearng, never play loud on headphones, even on speakers). It was connected to an AM broad bandwidth radio. Both were from the games PolyKyclomatic 501B and 1002 which allowed making electronic constructions connecting components with small springs. Each node of the circuit was a spring. When the miracle amplifier (as it was descibed on the manual) was built all i could hear was a click on the little speaker when connecting the 9 volt battery. i was so sad, i thought it did not work. i did not know that i should connect a music signal to amplify it. i miss them all as well as my godmother Soso who gave me her piano, Godfather George who gave me his Grundig single ended stereo radiogram, Godmother Elsa who tried to teach me some chemistry. It feels like they all still help me from above. My parents kindlty immedeatly bought for me these electronic construction games when they were seen at a 3rd or 4th class primary school party. The older brother or cousin of my schoolmate George or Dimitris were playing and experimenting when i opened a bedroom door by chance.

Eureka! Just a step up input transformer, one electron tube and a step down output transformer class A no feedback power amplifier, it works beautifully!

At your risk, please take every precaution. Eureka should not be used as it may not be important. But it is important to me. I have been building amplifiers since the age of 7 and now that i am 52 and feel like 18 it is the first time in my life that i can listen to a no resistor, no capacitor, just one electron tube, 2 signal transformers, and some batteries, music power amplifier. It is the Pleiades DL94 described on previous posts but further simplified. The DL94 electron tube is again triode connected> There are now 3 battery power supplies. Va is 2 x (AA rechargeable 1.2V) suppling heaters with 2.6V. Vb is 8 x (AA size 12V created by 2 4LR44 in series) supplying (anode connected to grid 2) with 94V through the output transformer primary. Vc is 2 x (CR 1/2 AA 3 volt) supplying control grid with -6V through the secondary of input transformer. That is all. It works and sounds mysteriously beautiful with huge bass from the big Sowter SK05s output transformers converting 2.5Kohms to 8 Ohms. The trick is also the input transformer which is a microphone transformer with a step up ratio of 1:12 so an extra voltage ampliying electron tube is not needed! On the more complex cathode resistor, electrolytic capacitor, coupling capacitor to grid version, bias was -4.8v by the 560ohm resistor, and anode + G2 (triode connected) current was 8.6mA. Now with -6.5V fixed bias current dropped to 6.3mA. So the ground connection should possibly be moved as on the French Radio Tubes manual from negative heater voltage to positive heater voltage since there is a distribution of electric potential across the heater filament. Or the bias supplied changed etc. Signal path. Careless Whisper - Wham or Big in Japan - Alphaville on original CDs - Sony CD Walkman line out - Pleiades DL94 - Celestionj Ditton 150 at listening distance of 1m to 2m - Small bedroom with low frequency panel absorbers wit enough reverberation in middle range. This amplifier sounds perhaps less loud that the cathode bias version with an uncertainty on whether there is some kind of subtle distortion, which may be becaude of less anode current since the fixed bias voltage seems to be too much. This on Careless Whisper. Big in Japan sounded like an undistorted 80s club. Every instrumenbt so clear, descrete, with decoded melody, undistorted. Even in loud passages since it is in class A amplifier ie electrons flowing all the time. i have never heard Big in Japan in this way. But it may be because it is the first time listening to it on CD. By the way these minimalist amplifiers including the Pleiades 2N3053 single transistor amplifier make the CDs a revealing experience with the missing octaves on high frequency added/ So it it sounds like a good quality close to master tape record. Listening test was with a monobloc amplifier fed by the right CD channel fedding the right loudspeaker.

A liitle instrumental

Just made up by Philippo, George while Fransesca was taking video and giving good vibrations. The melody repeats La, Si, Do, LA, Si Si, Do, La La, Si, Do,...etc. The bass is La, then Fa, then Re, then Mi. So suitable bass code ie harmony or chords is La minore, F majore with majore 7th, Re minore with majore 9th, Mi minore with minore 7th.

A Vc battery for bias

At your risk. Please take all safety precautions, including the millitary trick of one hand always in the back pocket. The Pleiades DL94 single electron tube power amplifier and almost nothing else except input and output transformer may be tried with fixed bias Vc of -6V. Panayiotis at Disios had the brilliant idea for the Bulgin AA battery holder to use 2 CR 1/2 AA 3V batteries by Varta in series inside the cylinder. 2 Bulgin 4 AA battery holders are being supplied by Fanos for the VB supply (see previous posts). Then one AA battery holder for heater Va. Hopefully with them the amplifier can be constructed to look exactly as the simple schematic, looking physical components from above. Then everything enclosed with see through plexiglass in color?

There is an analogy between single ended amplifiers and human speech, singing production

When we speak or sing there is not one entity pushing air and another pulling it. It is just one person doing the thing! A constant flow of air originating deep inside our body is being modulated by the vocal chords which control this flow like a grid inside an electron tube or electronic valve. A constant flow of electrons in a class A amplifier is modulated by a control element be it the grid, the base, or the gate. As the signal output from the amplifier tends to 0 so does distortion tends to 0. If we overdrive after limits distortion will become serious but gradually as everything else in nature with no negative feedback. Same with an output transformer, if one exceeds its limits. Gradually.

Tubes vs Transistors vs MOSFETs, is there an audible difference?

At your risk. Please take all safety precautions. The title is paraphrasing the beatiful article by|Russel O. Hamm... The Pleiades 2N3053 power amplifier in class A consists of just one 2N3053 transistor, a battery, a fuse, an output transformer, a bias resistor, and an input coupling capacitor. The Pleiades DL94 is almost the same circuit with a DL94 electron tube. It is about to be further simplified by building another one with no capacitors or resistors. Just an input ransformer, an electron tube, an output transformer, a Va battery, a Vb battery and a Vc battery for bias connected to the input transformer. The bipolar transistor 2N3053 may be further simplifier by including an input transformer and a similar kind of bias arrangement trough this input transformer. The input transformer is very important for the electron tube version as it provides x12 voltage gain, so that a driver electron tube is not needed and the whole job feeding the loudspeaker with music through the output transformer is done by just one electron tube. While explaining this to Panos, he sugested|i read Susan Parker's post on diyaudio on her push-pull, input transformer - MOSFET - Output transformer amplifier. Inspired by them why not making a Pleiades single ended MOSFET class A amplifier. Just an input transformer, a MOSFET and an output transformer. If the MOSFET is an enhancement type it may be possible to do away with external bias? But first trials will be with an IRF740 depletion type MOSFET given to me by Grigoris. The bipolar, electron tube versions sound so beatiful. How would all 3 types of amplifier, bipolar, electron tube, MOSFET compare on such similar, minimum component possible environment?

Transformers may be the most linear devices on the planet

Chances are we were conceived while our parents were listening to a song produced with many signal transformers. For example Take on Me - Aha, the lead vocal by Morten Harket sung on a Neumann U47 microphone which has the output transformer right inside it after the VF14 electron tube inside the mic... Anyway the nonlinearity of the metal is exactly compensated as the transformer produces and then reproduces itself. A varying electric field at the primary (the input music) is converted to a varying magnetic field, and then this magnetic field flowing inside the iron is converted back to an electric field at the secondary (the output music) by Faraday's law of induction. Furthermore since by this law the voltage is proportinal to the rate of change of the magnetic field, since increased music frequency means increased rate of change, it follows that as frequency increases magnetic flux must decrease to keep flat frequency responce. So distortion decreases too as frequency increases (only transformers and dynamic (moving coil) or ribbon microphones can do this) so they create very little intermodulations distortion compared to triodes, bipolar transistors or MOSFETs. Further reading: Audio Transformers - Bill Whitlock - PDF

A class A no feedback power amplifier with just an input transformer, a MOSFET, an output transformer, a battery and nothing else?

At your risk. Please take all safety precautions. What if an enhancement MOSFET is used, it is on at 0 volts bias so that step up input transformer is directly connected between source and gate. Then output transformer (with air gap to avoid saturation by DC current) is conneted to drain through a battery whose negative terminal is connected to source to close the circuit. Thats's all folks.

1st single electron tube power amplifier ever?

At you risk. High voltage is very dangerous, take all safety precautions. It works and sound amazing. The Pleiades DL94 single ended direct heated triode battery powered power amplifier in class A with an input transformer to drive the output electron tube to music beauty glory! So all needed is: an 1:12 input transformer, a 220nF coupling capacitor to control grid, a 560ohms cathode resistor with 220uF capacitor in parallel for bias and no local feedback respectively, a DL94 electron tube triode connected ie anode connected to screen grid, a Sowter SK05s 2.5K to 8 ohms output transformer, a 2AA battery holder with 2 AA batteries for heater voltage, 2 4AA battery holders for 16 4LR44 6V batteries (8 small paper cylindrs of AA size is constructed by wraping gently 2 4LR44...), 2 switches for low tension and high tension, a fuse for high tension, a fuse for low tension is also needed. It may be also possible to construct the same amplifier without Any resitor or capacitir (sic) by using 3 battery power supplies as in the early 1900s, Va for heater, Vb for plate (anode), Vc (-6V) for bias through the input transformer. This particular schematic looks like all 3 battery supplies connected in series, left Vc, middle Va, right Vb, negative side of Vc connected to one side of secondary of input transformer, other side to grid. Vb positive side connected to primary of output transformer. So far only the a bit more complicated version has been constructed on top of a red linoleum approx A3 size sheet, and all connections are done with Wago connectors. How does it sound like? 1st of all signal path: Careless Whisper - George Michael from Wham vintage compilation CD - Sony cd Walkman line out - (Sowter input transformer is inserted on Finder relay octal base, so if lower volume is needed a 1:7 Sowter octal transformer is pluged in insted of 1:12) so Pleiades DL94 as described above - Celestion Ditton 150 loudspeaker (so far just one monoblock power amplifier is made) at about 1m to 2m from listener - Small quite a bit reverberent listening room with 3 betoumin roofing felt low frequency absorbers inserted on big canvas panels, the big one is behind the speakers in this control room - listener. Only 0.4 Watts of pristine quality. It sounds huge, with deepest bass, amazing mid range, and untiring bass, mid, treble depth. The sax on Careless Whisper comes to life inside the room as all the instruments and George himself. Same for Is it a Crime - Sade for its miraculous recording with the amazing muted sparkling trumpet at the end, it sounds so lifelike, goosebumps to use a phrase from recording engineer bruce Swedien. The voice of Sade sweetest as ever even at high volume, same for Whitney Houston. This amplifier does not corrupt music at the loud moments of the song. It just overflows with music beauty. Why not, it is just one triode electron tube producing only its low order overtones at high levels. By the way the Pleiades one transistor 2N3053 (2 for stereo) sounds amazing too as it is the almost the same schematic, a bit simpler. It is possible that the electron tube version sounds even better, it is also higher powered 400mW compared to 2x100mW since the transistor version is at the moments powered by 12V at 12mA. the electron tube version is powered by 90v, 8ma. Many thanks to Vicky who first pointed out how amazing the Pleiades 2N3055 single transistor amplifier sounds. The versions with output transformer as those mentioned today are much more energy efficient and sound loud enough even with modern (non horn loaded) speakers which have so low efficiency. Output impedance of DL94 with particular ratio output transformer has been measured 11 ohms. So the output voltage increases a few dB for frequency where the inpedance of the speaker rises. Never the less the Ditton sounded huge and amazing with the Pleiades DL94. Unbelievable bass that caresses listener's stomach without sounding any boomy. If the cathode capacitor is disconected the gain drops, bass perhaps sound deeper. This amplifier recreates the beaty of music and makes the experience feel like a ceremony. An amazing tool for teaching yourself music.

A "secret" of George Michael vocal production technique

Double tracking his voice with a whispered one?! It was found by reading gearspace.com - George Michael vocal chain, with reference on SOS Faith, Older article.

The "secret" chord of We are the People - Empire of the Sun

Mabe i was assisted by I Say a Little Prayer for You - Bacharach which uses D bass and A minor on the right hand. So the chord I was trying forn years to figure out by ear is D bass and A #C E. So chorus is: C bass and E G B with B prepared as on Bach bass rules pdf then E bass and E G B, D bass and D #F A, then C bass and G B E, then E bass and G B E, then D bas and A #C E !. So really the chord code is D79

The complete schematics of Neve 1073 microphone preamplifier, line amplifier, low cut, eq

They can be thankfully found by searching: [pdf] Neve 1073 service information. By Technical Audio.

Irene Cara performing on Shure SM59

Irene Cara performs "Out Here on my own" from Fame - Letterman - Youtube. https://www.youtube.com/watch?v=nUnqhj5LnOw

Microphones used by Georgio Moroder

They can be seen on Georgio Moroder in the studio 1977 or 1979 - Youtube

Electric Dreams - Georgio Moroder story - Episode 1,2 - BBC Radio 2 - Youtube

Fairytale summary, How to love your SM58 at studio

The 2 cats, Kanelina and Lucy cry in distress as they cant get their SM57 to sound like studio recordings of Bono, Michael Jackson (SM7), Sade (SM58?). Thay decide to go to the beach to ask the wise seaguls seated on the rock. They do not know either but they study online the schematic of the M7 and sugest that they wind a similar inductor of say 170mH to 240mH (the SM7 manual shows 240mH), put it in an XLR barrel and connect it to their SM58. The 2 cats rush to the forest to find their friend, the patient tortoise to wind the inductor on an Siemens small toroid. The patient tortoise asks for a very thin ie 0.08mm wire. The 2 cats decide to go to Athens city center by metro train. In the train they meet singer Liliya who gives them sesame, honey bars. They then go to Stefos shop asking for 0.08mm wire. Vangelis and Aristotle say the cost of the whole spool is 300 euros, but the kind gentlemen let them wind on a small spool just a few meters... Everything goes well, thwy use the SM58 mic at 24in (apparently to compensate for equal loudness, voice effort curves, (not for proximity effect as there should not be any at 24in antway)), they get an amazing recorded vocal sound. They then all go down to the beach to sing along and dance with the seaguls under the early morning sun who leaves no shadows.

Are human beings, even singers, flat by nature?

We know from the first paragraph of the chapter Influence of the Mind on the great book: Sound and Hearing - Stevens, Warshofsky that the higher the intensity of the stimulus the lower the pitch as felt on our mind. So we sing what we think is the correct note but we sing flat. (flat by a few cents which is very annoying). So how does a grea world class singer sings in tune? Who knows? Could it be that they on purpose sing a bit higher and judge correctness in real time not by the pitch itself but by eliminating beats like a proffesional piano tuner? Or do they listen to the backing track at low volume? Or do they have the exact balance of backing track, their voice, by the record producer and recording engineer so that they hear both of them out of tune by the exact same amount? Or are they insensitive pitchwise to higher sound intenity? Anyway i tried to sing and record my voice, see next post, by trying to sign sharper in order to get the end recorded result correct, and it worked. Vicky commented also on real time experiments with my or her voice while playing the piano that when we increased our pitch untill we got it right it did sound very pleasing and bright, happy as sunrise. Trying to repeat the good result while hearing the same piano not or chord, it somehow feels as if there are 2 pitches to choose from and you have to choose the less obvious one. Go figure...Maybe it needs countless hours of training, is this what the greatests singers of all time do?

How to get an amazing vocal sound with a Grampian GR1, GR2 25Ohm ribbon microphone

At yout risk. This is how it was done a few days ago. 1. Mic at 24in from mouth in order not to have proximity effect, let the voice breathe, and micing not just mouth, but nose, head. Mic placed higher than head, perpendicular to floor. Mic was at a similar distance to the upright Pleyel piano with mic dead side looking towards the left side of piano, but it worked fine for the piano too. 2. A Pleiades step up transformer of 1:3 was used to step the 25ohms mic's impedance to about 250 Ohms. This transformer has a low primary inducatnce of 8mH to compensate for bass heaviness due to Fletcher Munson, voice effort curves. So with it the voice sounds very natural, with no bass heaviness, and the great quality, articulation, easiness, smoothness, and capture of emotion one would expect from a good ribbon mic. Actully this microphone had been re-reboned long time ago, see an older post. 3. After the step up transformer a pleiades gentle slope high pass filter of (130 Ohms,20mH) was connected in order to bring out the edge and higher overtones of voice as can be heared in great commercial recordings, for example, A Woman in Love - Barbara Streisand. Signal path: male voice singing kind of softly Everybody's Got to Learn Sometime - The Korgis, on average size living room - Grampian ribbon 24in to 17in from mouth (maybe >12in above head - Pleiades 8mH:78mH XLR to XLR mic transformer - Pleiades (130Ohms,20mH) XLR to XLR gentle slope high pass filter - XLR to 1/4in short cable - Sony TC-D5M (recording with limiter on) - TDK typeII cassette - Sony TC-D5M (playback) - Pleiades 2N3053 one transistor single ended class A power amplifier - Celestion Ditton 150 speaker - Small reverberant bedroom. (actually mic sounded better at about 17in). (Very impressive sound, getting close to a finished good quality product, singer tried to sing sharp so that the result does not sound flat. Thanks to Vicky for her comment on listening to the recording on her Musical Fidelity, Spendor system. She commentred how she liked the quality of the ribbon mic bringing out emmotion, on superb articulation and detail without artifacts.

Allen Sides discussion including microphone preamplifier UA610

It can be watched on youtube on A Conversation with Allan Sides by Vintage King

Watching the Stars

Remembering our origin, where we came from (Song writer Manos Hatzidakis phrase). What is important in life and free. Like watching the stars at night with or without someone. When we look at the sky we see the past. In fact we see the past on everything we look at as light takes time to travel... I am trying to remember never to exchange something precious for something of less value as Dale Carnegie sugests.

Love is in your heart

This is what Nobel physicist replied, paraphrasing, love in your heart is more important than equation in your brain. If memory is correct it can be heard on one interview of someone asking him to explain physics for his mother.

On the chords of Everybody's Got to Learn Sometime - The Korgis

In order to make it simpler to understant these so refined chords, lets's present them in the D minor key which has ony one flat ie B flat, all the other notes are natural or white at the piano keyboard. Bass D, A D F. Bass step descending to C to B natural but right hand keeps playing A and D and F! Bass B flat and code (as on Bach Bass rules pdf) becomes B6 ie Bass bB, bB D G. Repeat the 4 first chords. After "I need your loving which is bass D, A D F, F is kept and bass becomes A, so adding the usual 3rd we have bass A, A #C F, then Bass G, G bB D F then keeping right hand the same and changing only bass to C, bB D F, then the chorus, Bass A, A C E, then B7 ie Bass bB, A D F, then E7 ie Bass E, bB D G (brilliant!), ends at F ie Bass F, A C F. World class masterpiece. Actual key is #C minor (3rd) or bD minor (3rd).

Building electronic constuctions without soldering

At your risk. If this post is not mistaken NASA electronics are hardwired point to point. And we are taught to make a strong electrical, mechanical connection before soldering. Then why not just do only this and be able to build somethig even on the beach. Rescent Pleiades preamplifiers, power amplifiers have been built this way, the sound is amazing, no noise problem. See rescent posts, on using wirewrap technique, Wago connectors etc.

Why do electronics and music mate so well?

Music is really air molecules vibrating. An electronic signal is electrons vibrating. A microphone converts air molecule vibration to a corresponding electron vibration at its output cable. Welcome to the analog world!

Sound Picture Recording and Reproducing Characteristics - D. P. Lowe, K. F. Morgan - Journal of the Society of Motion Picture Engineers

Very important paper on creatingh flat frequency respone from recird producer's brain to listener's brain

What is a Pleiades microphone filter?

In many cases the signal from even a very high quality microphone is completely different from what the producer or listener has in mind. If a wrong for the purpose of a high quality recording (not sounding correct to the listener's brain) is fed to the signal chain (mic preamplifier etc) it may be too late to correct effectively without loosing quality. The reason for a microphone not sounding correct without a filter may be: Proximity bass boost effect, human voice recorded at low intensity but reproduced at high intensity, voice effort effect (when we sing sofly we create a broadband acoustic output, when we sing loudly we create a mid centered norrower band acoustic output. Great microphones such as RCA 77DX, Shure SM7 have the switchable bass reduction filter inside them so as to help the microphone preamplifier get the best possible signal or near to it. The Pleiades filter is just this, the inductor filter of say a 77DX, or SM7 etc being external put inside an XLR female to male barrel adaptor so almost any microphone can be used. The inductor is connected as on the classic microphones across the output of the microphone. For great high frequency detail the gentle slope high pass L,R (inducor in series with resitor) can be cascaded. So for example the signal path can be: microphone - Pleiades low cut filter - Pleiades gentle high pass filter - mic pre. Recently it was studied that the SM7 uses an inductor of 240mH. Recent Pleiades experiments showed that an SM58 at 16in can sound amazing with a 175mH to 175mH 1:1 transformer just after the mic and before the preamplifier. A high pass filter may not be needed as the capsule of the SM7, SM57, SM58 has an inherent high frequency peak. A Pleiades filter are usually put inside Neutrik XLR modules to create a nice looking XLR barrel adaptor that is small, light, beautiful with a color painted cetre for indentification of turnover frequency. The inductor is wound on a toroidal core so there is absolutely no noise, or noise picked up electromagnetically etc. Anyone can make a Pleiades filter, it is public domain as any other euroelectron or Pleiades idea that does not infringe a 3rd party.

How was the piano recorded on Clocks - Coldplay

Music studemt Jhanna sent an email to the record producer of Clocks-Coldplay, Ken Nelson who kindly replied to us on how the piano was recorded on this masterpiece. Blue Bottle mics with omni capsules fitted. They were placed about 2.5 feet above the strings and about 3 feet apart on Bosendorfer grand piano at Air studios in Hamsted, London.

Recording the piano

At your risk. Not at all easy. Large spaces help a lot, eg halls, tall ceiling, church, outdoors etc. Early reflections being recorded make a frustrating result. Recently better luck came while recording the big Yamaha grand piano at SNFCC library (books tower). It is a average to big recording space, high ceiling, acoustic treatment on walls, seats, one of the main walls missing (making the sound escape to the other areas) which makes a perfect or great absorber! The piano was recorded, while Aaron was playing, with just one vintage Electro-Voice 635a omnidirectional moving coil microphone. Experience recording directly to Sony TC-D5m with or now low cut filters sugests that no low cut filter is needed. Lid was closed (regulations of library), mic was at say 4 feet.

Liliya

It is a pleasure meeting by pure chance in the metro train Liliya. Smartly dresed on amazing italian shoes. Very kind like a princess. And a singer. Her youtube channel is Liliya.mp3 Thank you Liliya for the inspiration, your kindness and laughing joy you bring.

Beautiful air gap in signal transformer carrying dc

Watching the video interview on Allen Sides to Vintageking on the best studio equipment made by mankind, the UA610 preamp was mentioned. By briefly looking at a very low resolution reading and reading a comment on air gap used... It is very encouraging as Pleiades amplifiers are really naturally into this sort of thinking and doing. Class A operation (electrons flowing all the time) not just on the active device but on the output transformer too. Allen sides says the UA610 old version sounds so lifelike.

Some quotes of Edwin Armstrong

https://www.bookey.app/quote-author/edwin-armstrong (perhaps for me seize the day may not be appropreate as it places stress and hurry, and hurry actually creates delay due to accidents). Instead perhaps the Tao Te Ching quote "She or he who sails slowly, sails far" is more appropreate for me. All the other posts are so moving.

The greatest problem of mankind...

Paraphrasing form Edwin Armstrong's (electronic engineer inventor of broadband FM amongs so many other inventions). The greatest problem of mankind is not what we do not know but what we know and it is wrong.

One of the problems of mankind

By Michalis. If an old lady comes along and tells that in order to restore your lost hair you can do this, and asuming she tells the truth, almost no one will beleive her.

Some of euroelectron's mistakes

There are many but here is one. It was thought in the early days of euroelectron that mic should be next to mouth. Far from truth, 12in or more as seen on classic Columbia 30th street church studios photographed sessions gives an amazing vocal sound. Archtect and sound engineer Hatznicolaou adviced to mic the nose, not the mouth. Rescent Pleiades experiments as written on euroelectron are done with mic at 16in, above head at 45 degrees from head, micing the head, not just mouth or nose. Head vibrates too and emmits sound. So many values of inductance for microphone filter to compensate for the bass boost proximity effect can be erroneous. But they are still very much perhaps needed but the inductance must be higher since the bass boost starts at a lower frequency when a high mic to source distance is used. See for example the rescent post on SM58 using a 175mH to 175mh signal transformer at the output of the microphone. See also other posts made in the more rescent years for better values of inductance including the Pleiades gentle slope high pass filter made with 130 ohms in series with only 20mH and the total in parallel in microphone's output. Here the turnover point is high in frequency to create the sparkle that is so much liked in produced vocals but the series resistor reduces the slope so that the vocal sounds correct with correct body. The point to remeber is that it is not only proximity effect that needs to be compensated. There must be flat frequency response not only from mic to loudspeaker but from the whole chain, from vocal chords of singer to listener's brain. And if we take it further from producer's brain to listener's brain. See references, bibliography on past euroelectron posts.

Thank you Pano for showing me the way many years ago on JFETS, very simple schematic, with K163

The classic and of course ingenious anode or drain or collector follwer single eneded in class A (electrons flowing all the time) amplifier, sounds amazing and so low noise especially perhaps at very low currents for low noise small signal amplifiers. And such schematics of course sound amazing too for power amplifiers. Thank you Lefteris too for bringing to my attention the classic Neumann U47 microphone schematic, same configuration too.

Pleiades 2 K117 RIAA 9 Volt powered record player MM cartridge preamplifier operating in class A is ready in box

It sounds amazing and huge and lowest noise, see previous post. The size of the aluminium box is a bit more that a 7" single on one dimention and a bit less on the other. The lid may be made from transparent orange plexiglass. No soldering has been used on this. How? Everything was wirewraped, and small components were inserted in the Nickel brand from Taiwan breadboard. Even on the Neutril beautiful XLR female RCA D type chassis connectors a tiny hole and been created with a circular drill vice for hand making acuurate holes. Then the thing solid core teleco wire was wired around the signal terminal a few turns. Surprisingly perhaps then is absolutely on noise problem on the preamp. Everything sounds so big and at the same time low low even using the low output tiny Stanton EEE AR stylus. For hygenic, possible signal contamination problems, it was decided to stick to perhaps Nasa's point to point mechanical joints but without then using solder.

When given an extremely low volume, so low i could barely hear the backing track, even i could sing beautifuly in tune

Why do most of us including many singers sing out of tune and below ie flat rather than sharp?

One important explanation seems to be on the begining of chapter :The Influence of Mind, on the fabulous book Sound and Hearing - Stevens, Warshofsky created after so my experiment at the Harvard university's Psycho-Acoustics lab. At high sound intensity the brain hears the same frequency flater ie with lower pitch. So the singer thinks she, he is singing correctly in tune, but in fact everything is below in frequency by a little but very annoying amount. And this may make a potentialy hit song not a hit song at all. What do the Whitney Houston level singers do? Do they sing on purpose higher so that the mistake sounds correct? Do they get a very low volume output to their headphones so that their brain hears the correct pitch on the backing track? Do they have immunity to the pitch change by highter intensity? Do they get their voice loud enough on their headphones so that it sounds flat too as well as the backing track, and the producer fiddles with the mix until intonation is correct? Phil Ramonne on his book Making Records states clearly that whenever a problem of intonation by the singer is encountered the first thing to take care is the headphone mix... Also Sir George Martin states in his All you Need is Ears (if memory is correct) book that good singers when they say sing just a note on their own the result sounds in tune with itself, meaning (if memory is correct on reading the book) that the overtones of their voice sound in tune with the fundamantal to the listener's brain...

On making the Pleiades 175mH:175mH (not 200mH or 240mH as fewer turns of wire were used) microphone filter for SM58

As can be seen from the title it is a transformer ie there are 2 coils hugging each other, rather than just one coil as in ordinary Pleiades filters. So it not only low cuts but isolates too as each wire is not electricaly touching each other. They communicate through the music sent as an electromagnetic wave from one coil to the other. It may be called the Pleiades Liliya microphone filter if Liliya agrees. It took yesterday and today to make it. 0.16mm diameter wire was used. 2 small Leukosilk spools were wound with a few meters of such wire each. Then hand was holding the 2 ends of both wires and wound both of them on a wooden stick along its lenghth. The thin wooden stick has wood removed from its ends with a tiny file so that it can accomodate the wire. Then both wires were wound with the help of the wooden stick through the small Magnetec 073 nanocrystaline toroid. This way of simultaniously windiing 2 wires seems to be called bifilar. It looks as if only one wire is wound. Each wire at any point in space is at the same electric potential (voltage) to its pair. So there is no or minimal capacitance between them. Using a Siemens if memory is correct similar size ferite core wound bifilar way, the frequency response was flat up to say 450KHz! It was a nightmere to keep it extremely tidy without each coil jumping over the other but it still looks very nice. About 69 turns were wound for each wire to fill the toroid space and give an inductance of about 175mH for each coil which should also be great for omnidirectional microphones as a nice low cut of bass prominance of environment and usuful signal. The inductor was placed inside Neutrik modules to look really profesional and beautiful and today afternoon was ready. It was tested then with male singing voice indors, outdoors (noisy balcony) and staicase. Singing the phrase I like you just the way you are - Billy Joel. Mic distance was 16in or 19 in. Without the filter, ie mic on its own, the sound was bass heavy, full of boominess even at the balcony. With the usual German inline transformer of 230mH:290mH(?) (470mH at low frequency), the vocal sound much clearer, with very nice midrange, high frequency detail, just a bit of mudiness. With the just made Pleiades 175mH:175mH signal transformer bass mudiness from proximity effect etc was completly removed, midrange was very nice and big but a bit standing out too much, high frequency detail amazing, like a ribbon mic perhaps. The sound as heared sounded close to the Billy Joel quality as recorded by Phil Ramone on apparently a Beyer M160 double ribbon microphone. Anyway I am not Billy Joel. Signal path: indoors, or noisy outdoors, or staircase, male singer singing Just the way you are - Billy Joel - Shure SM58 Mexico at 45 degrees from above towards nose at 12in to 19in distance - Pleiades inline 175mH:175mH high pass filter transformer - Sony TC-D5M on Left channel - monitoring through its tiny spaker or Sennheiser HD-580 or Pleiades 2N3053 single transistor amplifier in class A feeding Celestion Ditton 150 in a small reverberent room The best recording was the one done on noisy (machinary and birds) outdoors. Actually a Pleiades (130 Ohms, 20mH) gentle slope high pass for adding crystal clear sparckle may not be necessary as the SM58 capsule has an inherent high frequency boost. Good luck if you decide to make one.

On getting a good studio master finished product quality take with a Shure SM58, SM57,...

Since Michael Jackson used an SM7 and possibly Whitney Houston while recording in the studio and by viewing the schematic on coutant.org we can see there is a low cut incuctor of 240mH inside the mic for creating the proximity compensating low cut filter... And since the SM57, SM58 seem to have the same capsule as the SM7... And since the inductor is connected in parallel to the output of the mic... Then why not creating an inductor and placing it inside an XLR female to male barrel adaptor so that we approach with many microphone what the legendes used... This is the idea behind the Pleiades inline filter created a few years ago and published on euroelectron. Also Michael Jackson sung with many cylindrical sound absorbers around him, possibly to extinguish early reflectrions. Fairly rescent Pleiades experiments are done using the fabulous acoustics of outdoors... Anyway, after meeting Liliya and then seing her performing live on youtube with her band possibly holding an SM58 it was decided to create a passive filter for an SM58, SM58, Unidyne III etc with an inductor of close to 200mH which surprisignly had not been made yet although most other values of inductance have alreay been used on Pleiades filters.

A simple microphone experiment for better vocal sound

At your risk. Needed a microphone, a recording device, could be even a mobile phone, A usual place like a living room, a extra quiet outdoors recording place. One take is recorded holding the mic above head about 12 inch from nose indoors. Then the same outdoors. You can be amazed by the difference outdoors makes. It sounds close, intimate, no s problems, no bluriness, focused, inteligible, less bass heaviness crystal clear, and the singer sounds much younger., It sounds profesional. One reason may be... no close reflections which come back to the mic very quickly since they are from close objects. It is usuful to remeber that the mic has no brain to forget capturing early reflections. See also the Motion Picture Engineering book refered to on older euroelectron posts. If a good mic is used compensated for flat frequency response from producer's brain to listener's brain such as passive inductor Pleiades microphone inline filters, to result can be amazing.

Hit Songs may need a few electrical signal transformers ( 2 coils of wire hugging each other) in the analog signal path.

Some microphones even have one inside them, for example Shure SM57, SM58, RCA 77DX, Perhaps AKG D25 etc. Why do they create a magical sound? They recreate the music signal as the first wire is not connected to the other, music energy is transfered by an electromagnetic energy wave. They may introduce a subtle high frequency rise, see Rupert Neve interviews on youtube...

Just 2 SM58 coincident pair at right angle to each other can cover a PA concert

It was tried at Castaniani village of magestic view in the north part of Hellas, full of maintains and super clean air. Shure SM58 has no bass boost proximity effect (ie frequency respone is getting flat) at say a distance greater than 1 meter. So mics were placed in front of conductor, singers were placed about 1 meter away in center, behind them there were acoustic or amplified instruments, behind them a choir. Each PA speaker was placed behind each mic, so that feedback would be minimum. The venue was outdoors on a magnifiscent August night. The Yamaha if memory is correct mixing desk was only used as an amplifier with perhaps a bit of reverb. Roadies were very releved that they had so little to carry. Everybody was happy after the concert and congratulations were given...

Did you know A.D. Blumlein...

electronic engineer, one of the best in the history of mankind, inventor of the modern stereo disc cutting method of 2 deegrees of freedom at 90 degrees to each other for each left, right channel while cutting the groove with music, inventor of the coincident mic pair technique with each directional mic at 90 degrees to the other... On the first date with his to be wife, he took her on a trip to the sky, flying with her an aeroplane... Reference: The Life and Times of Allan Dower Blumlein - Rusell Burns - IEE history of technology series

Microphone comparison: Sennheiser MD421-II, Neumann TLM 103, Electro-Voice RE20 with or without Pleiades gentle slope high pass filter (130 ohms, 20mH)

Only the RE20 was tested with or without Pleiades filter and its internal low cut was on at both cases. The test was done on 24011817 date time code at SNFCC studios. 2 women and 2 men of young age, active in the audio engineering were the listeners. The test was quasi blind in the sense that Lefteris was playing the different files, so he knew, Fotini, Fey might had been influenced by him as he was the first to vote everytime, and i may be biased as i could more or less guess which mic with filter was which, but the rest 3 of us did not know which mic file had been playing through the Genelec coaxial monitors. Kelly who had booked the session did not turn up being ill so it was decided to record Fey singing Hurt - Cristina Anguilera using the original backing track from the CD single. The recording room is small but treaed acousticaly. Mic was in front of singer at bout say 8-9 inch. i would have possibly prefared 12 inch for less proximity effect and from 45 degrees above singer's head. but we did not do much mic placement tests. An objective of this test was whether we could make a vocal sound as good as Christina's. And whether the Pleiades filter would make the sound close to that without further EQ. 1st mic is MD421 with its low cut almost full, (I guess it would have sounded better with full low cut). While we were testing before recording (mabe greater mic distance) i was impressed with the clear sound of this microphone. Score out 0f 10, Le:6, Fo:6, Fe:4, Ge:5 (George). Total:21 2nd mic EV RE20 with Pleiades in line filter. Le:7, Fo:8, Fe:7, Ge:5, total:27 3rd mic Neumann TLM 103. Le:9, Fo:9, Fe:8, Ge:3, total:29 4th mic EV RE20 with its low cut only, Le:7, Fo:5, Fe:6, Ge:3, total:21 i gave on 2 cases 3/10 as i was hearing bass heavines compared to Christina's original backing track + vocal that we were comparing. Lefteris commented that he was imagining how the TLM will sound after eqing it. We were happy that on the higher rated cases we could approach the quality of recording of Christina. Fey did a great singing job. Many thanks to all participants and SNFCC. The files may have been deleted.

Now all time euroelectron views is 247303

Currntly about 300 views per day. Thank you all!

Life is good

The Pleiades 2 K117 (9 volt) RIAA preamplifier

At your risk. It started as the inteligent Le Pacific Walters, Hiraga 2 K170 preamplifier which is elegant and simple. It consumes about if memory is correct 5mA per junction field effect transistor. So the 2 garage remote control 12V batteries whent down in a few minutes. Then the idea came to see if it would work with just a 9 Volt battery. It did not as the large Idss (5mA) created such large voltage drop at the drain resistor that the drain went down to a few millivolts. Then source bias resistors where added to reduce drain current, it worked. Then drain resistors when increaed from 2K4 to 10Kohms, to increase gain to 22Kohms and now to 100Kohms at the first stage. Drain current is just about 40 microamps and it sounds amazing and low noise as known from fascination with low currents on this Euroelectron blog. Sony does this too if your see the schematics of the ECM series electret condencer battery powered microphones. Again a few decades of microamps on the sensitive low voltage and low current music fed 1st stage. It is so low noise... The second stage has a drain resistor of 10 KOhms so as to be able to drive the 2N3053 power amplifier. The passive RIAA filter between 1st and 2nd stage is based on the Heathkit tube integrated amplifier built in kit form by Antonis Kaskampas who kindly almost donated this amplifier long time ago. The series resistor is 220K, the capacitor at this branch is 15nF and then a 5nf cuts the treble. The preamp had been tested with the inverse Lipshitz RIAA network and it is almost flat so far with + 3dB at 20Hz something which should be corected later on. So overal the schematic of the Pleiades 2 K117 9 volt batterey powered RIAA MM preamplifier is: input - cartridge terminated by 47K - coupling capacitor of 470nF - 1M sourse resistor - 10K source bias resistor in parallel with a 220uF electrolytic capacitor- 100K drain resistor of K117 - 220K series resistor in series with 22K in series with 15nF for the 3180ms and 318ms bass turnover frequencies and signal taken from the junction of the 2 resistors with 5nF to ground for the 75ms high cut (a small series resistor is added in series to 5nF according to The Tube Amp Cookbook - Allen Wright to stop cutting treble forever with respect to frequency increase) - signal is then fed to second K117 JFET gate resistor of 1M - RL2 is 10K - RS2 is 560R and the in parallel capacitor is 220uF - signal is taken from drain by a 820nF dc blocking capacitor - output. That's it. 2 such channels can feed 2 Pleiades 2N3053 power amplifiers. Amazing sound. If an Altec 5:1 or a Belclaire 10:1 output transformers are connected to the output of the RIAA preamp then the Sennheiser HD-580 300 Ohm per each drive unit headphones can be driven to a comfortable not loud volume.

Eureka!, Just 3 transistors from MM record player cartridge to Loudspeaker, everything in single ended class A operation, (electrons flowing all the time)

At your risk. It is so simple with minimum components and it sound amazing, huge bass, great mid smoothness and anazing treble. On a good record (see below) cymbals sound so good one can almost visualise the sound as what is seen when a small objest falls on a calm sea. This is how the attack sutain and decay of the cymbal feels like. And when the program material becomes busy as on the end guitar solo of To France - Mike Oldfield nothing sounds tiring to the ear, the sound is still big and clean. All this with so small power consumption. The RIAA preamplifier comsumes less than a millamper at 8 volts, and the power amplifier about 10-14 milliamperes at 24 Volts. Yet the sound level is ordinary comfortable without being loud of course. The transistors used are 2 K117 JFETs per channel for the RIAA preamplifier and one 2N3053 bipolar transistor per channel for the power amplifier. Signal path: Just the Way you Are - Billy Joel from a foreign pressing LP - Technics SL1200 MKII turntable - Stanton 680 or 681 cartridge - EEE AR stylus - Pleiades 2 K117 RIAA preamplifier with a 9 volt battery - Pleiades 2N3053 power amplifier powered by 24 volts (2x12V batteries in series with fuse), (Pleiades output transformers, see older post) - Celestion Ditton 150 speakers - small reverberent room - listener So far the other song played is To France - Mike Oldfield from a Hellenic pressing LP at the no longer existing Columbia factory in Athens.

Wago makes electronics as simple as drawing

At your risk. Wago 2 or 3 or 5 terminal connectors have been used to build easily the Pleiades 2N3053 single transistor class A audio power amplifier. Everything had been connected with Wago connectors, bias resistor, transistor, coupling capacitor, output transformer, fuse, battery, speaker. The transistor is fitted as follows. 3 IC like wirewrap female beens joined together are each wound with blue for collector, green for base and yellow for emitter solid wire cables. The transistor is inserted and the logers colored wires are inserted and fasten on Wago connectors. Wago connectors can be orianted so that the connecting holes look towards the ceiling, so for example a resistor can be fitted from above when its body is parallel to sea level and its legs are bent 90 degrees like the hellenic PI letter. So components are inserted from above like on a breadboard and the connections are done like what is seen on the electronic schematic. So far 3 monoblock power amplifiers had been built. The Pleiades 2 JFET K117 RIAA preamplifier has so far been built on ordinary breadboard from Korea which are very nice too for expeiments.