Friday, May 31, 2019
The inventor of the one transistor power amplifier for music
The earliest reference so far found is this: (earlier references are welcome at the comments section).
2 transistor miniature AF amplifier by K. Jones [Audio Amplifiers - Davies]
This elegant class A (electrons flowing all the time) design has the speaker itself instead of a (collector) load resistor.
(Such brilliant idea can be seen in hearing aids, vintage books on electron tube radios with one electron tube and headphones instead of a load resistor (at your risk). The Pleiades Electra headphone amplifiers use this idea too.)
In the Jones inteligent circuit an AD140 powe transistor is used for driving the 16Ω speaker. An OC44 emitter follower transistor for driving the AD140 base. Bias and negative feedback is from AD140 collector to OC44 base by a 33KΩ resistor. An 6.8KΩ base to ground resistor is connected to OC44 base. A 10μF input capacitor. A -6V battery (At your risk always use a fuse in series for fire hazard protection etc).
Immediatly impressing sound quality of this circuit.
Driver transistor was blowing all the time, possibly due to lack of heat sink.
All Pleiades lab did was to remove the driver transistor and possibly the feedback resistor connecting bias resistor to Vb. not sure yet if emitter follower is needed but modern signal levels from CD player seem enough.
Through the years the AD140 was replaced by 2N3055 and of course changing polarity to +6V as 2N3055 is npn. 2N3055 gives more treble but there is something nice about the germanium transistor sound. Possibly electron mobility? An electron behaves as lighter in Germanium than Silicon.
Changing supply to 9-12 volts and adding a french key heat sink (at your risk a proper heat sink should be used for safety). Recent change is using the BD139 as an output transistor which gives even better sweet extended treble.
A recent schematic is:
(As of writing this the Pleiades BD139 feeds a Zeiss Ikon cinema cabin fullrange speaker to great sound quality around many rooms. CD playing is a Foreigner compilation including I Want to Know what Love is).
https://euroelectron.blogspot.com/2019/05/pleiades-one-transistor-emitter.html
Reference:
Audio Amplifiers - J. R. Davies - Data Publications Ltd - London - copyright 1968
Genuine Toshiba 2N3055? and opened transistor photoelectric effect
Toshiba 2N3055 genuineness - flodins - YouTube
https://m.youtube.com/watch?v=ZG15k29yT0o#fauxfullscreen
The Toshiba 2N3055 on the Pleiades 2N3055 one transistor amplifier may be a fake one. It had never been opened. Yet it sounds good. Perhaps due to the low voltage and current operation.
The BD139 gives better high frequency detail or extension, see previous posts.
Zeis Ikon typ:31-06 baffle fullrange speaker with Pleiades BD139 one transistor power amplifier
Have I been missing all those years?
It sounds much louder than when the linoleum Auratone 5C type speaker is connected. About 2-3 times. Strange how the amp is so low power at these settings, possibly much less than 1W yet it is not desired that system were louder.
One reason is that it has impedance 12Ω which matches closer to the relative high impedance of the BD139. The Tesla 5in speaker is 4Ω. The BD139 was supplied with Vb=12V through series fuse for safety. Bias resistor 12KΩ. Playing the CD albums, Ray of Light - Madonna, Ingenue - KD Lang
This setup can transport to the artists brain. This is what had been thought while listing to the wonderfully played guitars on the Ingenue - K.D. Lang album
Amazing sound with full bass, clear mid, relaxed extended treble.
No crazy wooden box bass, mid bass air standing wave resonamce modes etc.
This wonderful Zeis Ikon speaker baffle was placed spaced in the corner of the reverberant room.
More information on the 31-06 speaker in a previous post.
Also here:
https://www.audioasylum.com/messages/hug/158435/speakers-amp-drivers-by-zeiss-ikon
Variable Amplifier Impedance - Rod Elliot
An interesting article:
http://sound.whsites.net/project56.htm
See also:
Nelson Pass
On analog tape recording, record heads are constant current driven by a large output impedance.
A microphone can constant current drive a Pleiade L filter (inductor in parallel). Pleiades (R,L) filters produce a gentler slope rising treble (gentle slope low cut or high pass).
An omnidirectional speaker?
It is not really omni but it may be fun.
Starting with a linoleum Pleiades Auratone 5C type speaker enclosure and mounting 2 5in drive units back to back as in previous post.
So one drive unit on front side, one on back. But both drive units fed in phase.
Presure builds up and releases. Linoleum would expand like a ballon and radiate low frequencies rather efficiently due to a relatively large vibrating area. Perhaps similarly to mounting one drive unit but more pronounced presure variation effect.
Two 4Ω drive units in series would have 8Ω impedance.
Thursday, May 30, 2019
Can a dipole speaker be made by mounting another speaker on back side in antiphase?
How would it sound differ from a speaker without cabinet or baffle?
Possibly more bass as there is some path from one speaker to the other created by the sides of the cabinet.
See also previous post.
Disadvantages. More weight. More cost. 2 sound sources, not a point source.
Advantage? No radiation from the sides of the enclosure since acoustic waves cancel out, one speaker produces positive presure while the other one negative.
A push pull speaker
For example adding a driver on the back side of speaker cabinet.
For example on the linoleum Pleiades Auratone 5C type cube speaker having one fullrange speaker normally on front side. Another one on back side.
Speakers connected in antiphase.
So no presure is built up inside. And standing waves canceling out.
A dipole speaker?
Increasing efficiency of Pleiades BD139 one transistor power amplifier
What to do?
Rumor has it that output impedance of amplifier might be of the order of 70Ω but speaker is just 4Ω. Impedance mismatch means reflection of energy going to speaker back to the amp. A nice electromagnetic wave travels along the speaker cable at almost the speed of light. Until it arrives it does not know what impedance it will find. When it arrives it feels the almost short circuit compared to 70Ω and voltage then drops? Transistor is ignorant yet of what is happening until almost short circuit of 4Ω wave arrives back to it. Surprise surprise. Then voltage across transistor drops due to 4Ω load.
Where does the 70Ω estimate comes from?
Possibly roughly from deciding Vb to current. When Vb is say 10V current measured is about 100mA, 10V : 100mA is 10V : 0.1A is 100 V/A is 100Ω.
How to impedance match?
One option:
Rewinding a Tesla speaker coil with more turns and less diameter.
A patient tortoise might do it.
Or sing many BD139 Ttansistors in parallel?
Or using an output impedance matching transformer?
The Pleiades BD139 still operates at Vb=7V
Playing with the Pleiades BD139 one transistor amplifier and almost nothing else.
Biasing rssitor is 12ΚΩ. For schematic see yesterday's post etc.
DC voltage across 4Ω Tesla speaker on linoleum Pleiades Auratone 5C type cube is 300mV.
So current is less than 100mA.
Amplifier still sounds very nice, not loud.
It might be a good exercise to see how loud can this setup be made without losing the quality of sound.
See also next posts.
Comparing 2 Fostex M88RP membrane ribbon microphones of different vintage
The newer, (the first coming to the Pleiades lab), has serial number 604020. Both mics look identical but the mic body of this is printed:
Fostex M88RP Bidirectional Printed Ribbon Imp.Low Japan
The mic storage case says:
Fostex Printed Ribbon Microphone
The older vintage has serial number 107038.
Mic body says:
Fostex M88RP Bidirectional Flatcoil Dynamic 600Ω Japan
The case says:
Fostex (with much smaller letters) Regular Phase Dynamic Microphone.
They sound very different, both world class.
The newer is also 600Ω. This had been measured? on an ac signal tone emmited by an impedance meter. DC will damage any ribbon mic.
It sounds as if the bass cutoff is much higher.
Not known if this is from a differently tuned diaphragm resonant frequency, or internal input transformer of lower input inductance.
This mic gives a mid heaviness for vocal use at 7in distance if the mic is used without a Pleiades (R,L) gentle slope high pass filter.
The older mic has a much lower frequency response. This can be heard in ambient noise capture. It can also be confirmed by gently tapping the mic body producing a bass sound.
At 7in vocals without a Pleiades filter the sound is bass and mid heavy.
With the Pleiades (130Ω,40mH) inline XLR filter used inside a Neutrik module adaptor with painted blue stripe, the sound of both mics is natural approaching flat frequency response from singer's brain to listener's brain.
With the Pleiades filter removing unwanted mid or unwanted (bass, mid) in the latter case both mics sound beautifully clear and natural. The lower bandwidth mic sounds a bit more reasonant which can be a good or bad thing depending on application. It may give a wanted edge detail to voice.
The higher bandwidth mic sounds more relaxed with also great treble, bass and midrange.
Both mics have amazing treble with no hint of s problem.
These mics with said filter can possibly be used for producing a sound quality such as:
When I Fall in Love - Nat King Cole
The Power of Love - Frankie Goes to Hollywood
Signal Path, Setup:
male singing voice - Fostex M88RP at (7-9)inch - Pleiades (130Ω,40mH) - Sony TC-D5 Pro - Sennheiser HD580
The Pleiades (130Ω,40mH) EQ is just 65Ω in series with 40mH in series with 65Ω and the total connected to pins 2,3 if mic transmision line cable.
Musical Fidelity A1
Remembering so may years ago listing to this amplifier, very nice sound. It was possibly with turntable, moving cool cartridge with tiny Ortofon (RCA adaptor) step up MC transformers.
Schematic can be found here:
musical fidelity A1 schematic Google search images
Design by Tim de Paravicini:
https://en.m.wikipedia.org/wiki/Tim_de_Paravicini
BD135 driving 2N3055, BD136 driving MJ2935 at the output stage operating in class A (electrons flowing all the time).
more information on Musical Fidelity A1
https://www.markhennessy.co.uk/mf_a1/technical.htm
Single ended BD135 vs BD139 power amplifier
BD135 is a lower voltage version.
This was tried today on a Pleiades BD135 one transistor amplifier .
It sounds very nice. Not sure if it is better than BD139.
Sticking for the time being with BD139.
Wednesday, May 29, 2019
Πως ειναι η φωνη τοςο καθαρή στην Χιπ Χοπ; How is voice bass heaviness eliminated in hip hop!
Ένα κόλπο ειναι πιθανοτατα ελαστομερες μεμβράνες σε απόσταση απο τους τοίχους για την αποροφηση της αντιχησης των χαληλων συχνοτήτων. Κοινώς μπασοκυματοθραυστες.
One trick is possibly elastomer membrane absorbers spaced from walls (where air particle velocity is non zero). Elastomer membrane panels like receiving rather than transmitting woofers vibrate with bass energy converting bass reverberation to heat. Anti woofers. So bass is captured clear and big.
See also other euroelectron posts.
Dr Dre
https://m.youtube.com/watch?v=uXo0TrMhPao
These guys know what they are doing. A mix not bass heavy or treble heavy so that it sounds correct to listener's brain when not played softly. Equal loudness curves.
At 7:50
A bass pattern with diminished 5th
G# D C# G#
Membrane bass absorbers?
Eminem and membrane bass absorbers
Not sure but if the studio is Ocean Way, then the membrane absorbers would be the ones designed or made by Bill Putnam and a photo of them can be seen on the Pet Sounds back cover photos or Mamas and Papas studio vocal tracking photos.
Great clear sound with no bass reverberation heaviness.
How would such absorbers sound if made of linoleum?
Or would Bill Putnam have used linoleum?
Producing 2nd harmonic distortion by an asymmetrical power supply?
At your risk.
How would for example BD139, BD140 complimentary pair sound with a power supply of -9V 0 11V.
In class A (electrons flowing all the time) through devices.
A DC offset at output would make electrons flow all the time through speaker as well.
Asymmetrical overload creates 2nd harmonic distortion or othe even order overtones. [Terman]
But mabe that's enough with push pull as a single ended class A amplifier sounds great, can produce even order overtones and can be made with just one transistor. See for example Pleiades 2N3055 or Pleiades BD149
At your risk.
Reference:
Radio Engineering - Terman - McGraw Hill
Auditioning the BD139 transistor on Pleiades one transistor power amplifier
Same schematic as 2N3055 but with BD139
https://euroelectron.blogspot.com/2019/05/pleiades-one-transistor-emitter.html
Vb=9.8V, base bias resistor 10KΩ, current through speaker 500mA. Class A operation (electrons flowing all the time). Possibly needing a bit more than 10KΩ to reduce power consumption when listening at low levels. Persons a ganged potentiometer, ie 2 potentiometers moving together, one fir volume one for optimum buas. Or perhaps even better 2 sepatate potentiometers, the user adjusting for best sound and less power consumption.
Very nice sound.
Sweet, warm, excellent: treble, mid, bass, transient response.
BD139 was kindly suggested by Mr. Sideris while visiting his electronic parts shop in the centre of Athens.
Life is interesting. A 30p transistor may send to the cleaners amplifiers costing K€.
Later addition: BD135 had been tried the day after:(br /> https://euroelectron.blogspot.com/2019/05/single-ended-bd135-vs-bd139-power.html
Tuesday, May 28, 2019
Throwing a small ball at a membrane sheet of linoleum
First throwing the small rubber tennis size ball to a bare wall. Ball bounces dramatically, due to mechanical impedance mismatch. Energy reflects back.
Then throwing the ball at a membrane 1m x 1m or so of linoleum spaced from the wall. Ball dramatically freezes (velocity becomes 0 and stays 0). Ball therefore drops vertically to floor.
A similar situation must be for bass acoustic energy finding linoleum on its path. Linoleum breaks the wave.
A nice 1m x 1m large woofer behaving as an anti woofer.
Energy is absorbed by linoleum ie converted to heat. Energy is dissipated to deform linoleum. Linoleum then gets back to its shape after a while. A nice elastomer hysterisis loop. The temperature of linoleum slightly increases. Good deal.
Linoleum as low frequency membrane absorber was first read on the great book:
Acoustics for Radio and Television Studios - Gilford - BBC
Hanging linoleum Pleiades triagle base pyramids from the ceiling
At your risk. Take all safety precautions.
For example hanging the speaker using a very strong opaque string.
How would they sound like? Would bass increase or decrease?
Listening to WE417A, grid at space potential
Continued from the previous today's post.
At your risk. All safety precautions should be followed when working with any voltage or current.
A Saratoga (from Collins equipment?) 5KΩ to 4Ω output transformer is connected to anode circuit of WE417A. Actually the transformer is a Chicago Transformer Div 677 0430-009, similar to Saratoga Industries TF1A13YY 5KΩ, 35mA to 600Ω or 4Ω.
Sony CD Walkman bridged line out is connected to floating grid through a coupling MKT? blue Philips capacitor of less than 820nF.
The linoleum Pleiades Auratone 5C type little cube monitoring speaker is connected to output transformer.
The Power of Goodbuy - Madonna is used for testing.
First test is at about 80V anode potential, 8mA anode current. Very clear sound. A bit boring? Not loud at all. It seems electron tube is musically under driven.
It is noticed while monitoring anode potential that it increased to about 200V. Disconnecting the CD line out it returned back to 100V. It seems the extremely high impedance of an open grid electron tube is a so sensitive condition that even the slightest leakage of a capacitor?, RF energy? can be read. Later addition: No, it seems this happens due to the grid rectification effect, electron tube may behave as an automatic gain control amplifying device. See below or other posts.
Sound as mentioned is not loud. A 1:10 input transformer is connected between CD player line out and electron tube, through the same coupling capacitor sending signal to control grid. There is severe distortion. A big sound with bass. Of course bias does change also by the grid rectification effect.
A Sowter transformer of 1:3 was connected. Less distortion but electron tube still overdriven.
10KΩ series resistor to power supply of 370V was tried. Anode current increased to 20mA. Anode potential is greater than 200V. Electron tube is somewhat exceeded from max plate dissipation power. Sound a bit louder. Still not as impressive as expected. The Pleiades 2N3055 (a fake 2N3055?) one transistor amplifier, so small and simple, is more preferred.
During these tests the grid potential was measured to go as low as -1V. Open grid biases itself from electron cloud and the grid rectification effect from input signal. The latter is a bit like a compressor side chain. It should happen on Neumann U47 too at high SPLs. Gain reduction by change of bias. Automatic level control.
Open grid seems not to work very well so far for this application. Problem seems to be the fact that the electron tube settles to a relative high anode voltage and relatively low anode current. Ie too less transconductance. Later addition: It sounded nice on following experiments.
Pleiades bias with a high MΩ resistor from anode to grid will be tried and as little anode voltage as possible for getting say 30mA anode current. How would it sound like?
It may seems strange to bias from anode to grid but it must be remembered that grid is already less than -700mV by cathode emitting electrons. So Pleiades bias is pulling up bias from a negative value to a less negative one.
Another observation was that when switching off the amplifier and back to on a few seconds later, sound was louder. Possibly due to the reduction of cathode temperature making grid bias less negative.
A potentiometer will also be added after the input transformer for volume control.
Pull up bias will also be tried by connecting grid to positive cathode through a less high megohm resistor.
Cathode resistor pull down bias will be tried too. Pull down bias is needed as in such cases grid is returned without a coupling capacitor to ground. Cathode is connected to ground through the Rk resistor. Since cathode is at 700mV positive with respect to grid by lack of electrons to electron cloud if Rk were 0Ω the grid bias would be forced to become from -700mV to 0 V possibly damaging the electron tube by excessive anode current. Cathode resistor creates such voltage drop as to bias the electron tube back negative. More or less negative than free grid should depend on value of cathode resistor Rk.
Later addition: after a few days open grid or grid at space potential has been retried with input circuit etc hard wired. Sound very nice. So far indistinguishable (or better?) from pull up bias from cathode to grid with 10MΩ resistor and cathode to ground. See forward in time post:
https://euroelectron.blogspot.com/2019/06/we417a-5842-electron-tube-with-pull-up.html
WE417 electron tube with grid at space potential tests
At your risk. Any voltage or current can be very dangerous, all safety precautions should be strictly followed.
When 6.8V heater voltage is connected grid wrt cathode potential becomes more than -700mV. This is possibly due to cathode becoming positive by emmited electrons, positive protons remaining to it.
High tension power supply is 370V.
Cathode is connected to ground or Vb minus.
Grid is unconnected or floating or at space potential.
A 47μF 400V capacitor is connected across cathode.
The positive side of said capacitor is connected to red cable probe of a mA meter. Black cable probe is connected to anode. So anode voltage can be supplied and anode current can be monitored.
A voltmeter is connected across said capacitor.
A few watt 47KΩ series resistor from high tension charges capacitor.
Said resistor can be interminantly connected to capacitor in order to adjust voltage on capacitor.
So the anode is fed by a high output impedance power supply. Almost a constant source. If suddenly a high anode current might flow there would be a great voltage drop at series resistor thereby lowering anode voltage and protecting the electron tube. It can be thought as a 47KΩ load resistor. A current limiting resistor. (Initially a 1MΩ resistor had been tried which obviously created a low frequency oscillation, about 1Hz.
When anode voltage is say 24V there is very low anode current.
At about 70V it might be less than 1ma.
But at 86V anode potential the anode current became about 5mA. Floating grid voltage remains to less than -700mV. Actually potential is increased by the shunt effect of the voltmeter input impedance. In other words grid potential is actually more negative than measured. Voltmeter takes electrons from grid and sends them to electron deficient cathode while making the measurement. This can also be confirmed by anode current increasing when connecting the voltmeter. Bias is reduced, anode current is increasing. The negative lead of the 10MΩ voltmeter is connected to cathode. In other words returning grid circuit to cathode is pull up bias too as cathode is positive with respect to grid.
The WE417A electron tube should power amplify audio at 86V, 5mA conditions.
Changing to 390KΩ. Anode current became 6mA. With 270KΩ, anode voltage is 88V, anode current 8.5mA.
Changing to 10KΩ series PSU resistor . Anode voltage is 105V, anode current is 19mA. This looks great for a class A (electrons flowing all the time) music signal power amplifier. Would it work? How would it sound like?
This post is continued on next post. Output transformer is connected.
How would a linoleum made radio or Bluetooth triangular pyramid sound like?
Or an electric or bass or acoustic guitar amplifier?
Or a triangular pyramid amp speaker feeding a reverberation chamber?
Τι ειναι σωληνες ηλεκτρονίων και πως λειτουργούν; what are electron tubes and how do they operate
On an recent earlier post in Hellenic language.
https://euroelectron.blogspot.com/2019/05/blog-post_26.html
Linoleum cylinder makes a big difference in low frequency absorption
A small sized tiled bathroom was used for this test.
Bass modes were very prominent on male singing voice.
Inserting in the small room a cylinder of 107cm height of linoleum roll almost extinguished the bass heavy resonances.
Cylinders has the added advantage of diffusing reflections. See drain pipes in reverberation chambers of Abbey Road Studios, BBC studios mentioned in an older post.
First triangular base baby pyramid paper prototype speaker
Made by Vicky.
Looks very nice.
Not used with a drive unit yet.
Monday, May 27, 2019
How would a schematic like Neumann U47 sound as a loudspeaker driving power amplifier?
For example a circuit like the Pleiades V6 mic booster amp with a low plate resistance, high μ electron tube?
Perhaps a WE417A?
An electron tube is a physics lab in itself
At your risk. Take all safety precautions when working with any voltage or current.
First time playing with a particular electron tube is like meeting someone very special.
The WE417A preliminary tests at open grid
At your risk, take all safety precautions.
The amplifier is currently on the balcony.
The input impedance of the voltmeter used is very high to high (it depends on automatic range scale). From 1GΩ to 10MΩ.
Firstly measuring cathode to grid voltage with grid open and no power supplied. It is just 2-3mV. But today it is very cloudy. If there was direct sunlight the photoelectric effect may had produced hundreds of millivolts.
When supplying 6.8V at heaters the potential of grid with respect to cathode decreased to -700mV. Actual value is expected to be less than -1V. Systematic error due to the lowering of input impedance of the voltmeter used as range scale automatically increases and impedance lowers down. Using an electrometer or pH meter should give the correct potential of grid. The space potential?
Why is the grid negative anyway when heater voltage is applied?
As soon as cathode temperature increases electrons are thermo emmited (boiled off) from cathode.
But number of positive protons inside cathode remains the same. So cathode becomes positive. Or in other words grid becomes negative with respect to cathode.
Another way to look at it may be the (negative ) electron cloud near the grid.
A negative bias without even touching the grid may be good news for starting supplying an anode potential, carefully increasing from 12V.
(In fact reducing this already negative bias by an external high Z anode to grid resistor is what makes very low voltage operation possible on the Pleiades V6 low noise microphone booster or front end amplifier.)
Increasing the plate supply more than needed can have a very dramatic effect on an open grid amplifier as at some point the anode filed will start to penetrate the grid. Anode current may inceease too suddenly.
Anyway, how would this amplifier sound like if increasing the anode potential to such a value that anode current (at open grid) becomes say 20mA? Cathode connected to ground.
Grid at space potential.
The music signal coupled to grid through a capacitor.
Baby electron tube or transistor power amplifiers
The idea is an amplifier that does not need a fork lift.
An amplifier that can be comfortably held on the palm of hand.
Of excellent sound quality.
Operating in class A (electrons flowing all the time).
Low power (less than 1000mW) so that a conversation can be comfortably kept in the listening room.
Possibly battery powered.
Possibly one transistor such as Pleiades 2N3055 amp. Or one electron tube, WE417?
Baby output transformer if needed but of 20Hz to 20KHz bandwidth. It should be possibly as power out is low. Baby electron tube. Something cute.
An efficient baby power amp approaching the theoretical 50% efficiency.
Baby power amps should play well with baby linoleum Pleiades pyramid or cube (Auratone 5C type) fullrange speakers.
Inductance of various output transformers
Inductance is very important as it dictates together with driving impedance the low frequency cutoff.
It is not that the transformer cannot pass the low frequency.
It is not that the electron tube cannot reproduce the low frequency. Electron tubes like transistors go down to 0Hz. Descrete active components have tremendous bandwidth. It is surrounding components including parasitic components such as stray for example enclosure capacitance that create restriction of bandwidth. [Storey].
The low frequency voltage never arrives at the transformer primary because it is dropped at the output impedance of the electron tube. R and L form a potential divider. We know that the magnitude of the impedance of an inductance L decreases with frequency. The lower the frequency the lower the impedance the more of a short circuit the electron tube sees, the more the voltage drop at the terminals of the electron tube or any other source due to its internal impedance (conservation of energy).
For reproduction we can aim for such inductance that frequency response starts from say 20Hz or 10Hz. The higher the output impedance of source the higher the inductance must be.
For production we may aim for an inductance, winding resistance (R,L) such that for example when connecting a microphone to such input transformer flat frequency response results from producer's brain to listener's brain. Otherwise severe bass heaviness can result due to many reasons including psychoacoustic ones [Lowe, Morgan]. See also Pleiades (R,L) filters.
While preparing Pleiades lab for making a single ended WE417 low power amplifier in class A operation (electrons flowing all the time) some transformers had been measured with the Escort digital LCR meter.
Inductance of some output transformers:
Sowter SK05S, 13.4H to 22mH
Hammond 1626, 14H : 11mH
Saratoga Collins 9.8H : 6.2mH (1H for 600Ω winding) see other posts
Secondary of output transformer of Bouyer ST3 amplifier:
6mH, 12mH, 22mH for 4Ω, 8Ω, 15Ω respectively.
2 interstage transformers:
Sowter 9040s (no air gap by sample mistake?) 200H : 10H
Sowter 8423S, 95H : 18H
References:
Electronics - Neil Storey
Sound Picture Recording and Reproducing Characteristcs - D. P. Lowe, K. F. Morgan - Journal of the Society of Motion Picture Engineers
See also:
Magnetic Circuits and Transformers - Staff of MIT (Massachusetts Institute of Technology)
Sunday, May 26, 2019
Φάρμακο για δυσκοιλιότητα;
Η ψηφιακή ηχογραφιςη;
(Με δικη σας ευθύνη, δεν αποτελει ιατρική συμβουλή).
Οι 3 σημαντικότερες δημοσιεύσεις στην μουσική, ηλεκτρονικά, ηχογράφιση
Στο προηγουμενο post:
https://euroelectron.blogspot.com/2019/05/the-3-most-important-papers-on-music.html
The 3 most important papers on music, electronics, recording
Possibly the best papers ever written on the planet.
On how music or our brain works:
Bach Bass Rules - Bach, Niedt
On how electron tubes operate:
Operating features of the Audion - E. H. Armstrong
On flat frequency response from producer's brain to listener's brain:
Sound Picture Recording and Reproducing Characteristics - D. P. Lowe, K. F. Morgan - Journal of the society of Motiin Picture Engineers
Now that you know it is time not to be afraid as fear does not even exist.
2 relevant publications:
Enchiridion - Epictetous
How to win friends and influence your environment - Dale Carnegie
But possibly the most important to know is that cheap vegetable oil, palm oil, palm fat, margarine etc contained (for cost saving) in mass produced packaged food clog blood arteries.
What's the use if next day you die from heart or brain attack? (At your risk, this is not a doctor's advice)
See Trans Fat - Wikipedia etc.
Πως λειτουργει ενισχυτής με σωληνα ηλεκτρονίων κοινώς λυχνία, λάμπα, λαπα, λαμπιονι κτλ
Ευτυχώς στην χώρα μας τώρα που βγαίνουμε απο την επιστημονική κριση αρχίζει να εκλείπει η έκφραση:
"Αμάν εσυ και τα λαμπιόνια σου"
και σιγα σιγα επικρατεί η έκφραση
σωλήνας ηλεκρονιων
Το ίδιο και με το κιβώτιο ταχυτήτων του αυτοκινήτου που αποκτάει πια το σωστό του όνομα, κουτί γραναζιών, gear box. Δεν ειναι παρα ενα καλα σχεδιασμένο κουτί με γρανάζια. Οσο για τις ταχύτητες και τις συχνότητες και τις ελευθερίες, μουςικες κτλ δεν υπαρχει τίποτα απο αυτα, υπαρχει η έννοια ταχύτητα, συχνοτητα, ελευθερία, ελπίδα, μουςικη κτλ. Οι μούσες ειναι πολλές...
Που χρησιμοποιούνται οι σωληνες ηλεκρονιων στη μουςικη;
Μεςα στο μικροφωνο που μπορει να χρηςιμοποιει η Madonna αν εκεινη τη μέρα χρηςιμοποιει σε ηχογραφηςη πχ το μικροφωνο Neumann U47.
Η στο τραγουδι Take on Me - aha οπου γνωρίζουμε απο τον παραγωγό την χρήση του U47
https://en.m.wikipedia.org/wiki/Neumann_U47
Αλλα και σε προενισχυτες μικροφωνων οπως Telefunken V72, πχ Καζατζιδης και τόσοι καλλιτέχνες την χρυςη εποχή του Ελληνικυ τραγουδιου, Beatles,...
Σε Pultec EQ (μηχάνημα) (η Pleiades (R,L) filter χωρις απαραιτητη τη χρηςη σωλήνων ηλεκτρονίων) για να ακουστεί η φωνη σωστά απο τον εγκεφαλο του παραγωγου στον εγκεφαλο του ακροατή, [Lowe, Morgan]
Επισεις στην αναπαραγωγή μουςικης σε προενισχυτες, τελικούς ενιςχυτες κτλ.
Ενιςχυτης σε τάξη Α σημαίνει τα ηλεκτρόνια να ρέουν για καθε χρονική στιγμή. [Gray]
Και τα τρανζίστορ [Hamm] ακούγονται απίστευτα φτάνει το ηλεκτρονικο σχέδιο να μοιαζει, να χρησιμοποιούνται λίγα και καλα χωρις αρνητική ανάδραση η ενα. Less is more.
Επιςεις ολα τα παραπάνω βοηθάνε να μην πάθει κανεις ευκοίλια σε περιπτωςη που η ηχογραφηςη γινεται σε ψηφιακό η digital domain.
Πως λειτουργούν οι σωλήνες ηλεκτρονίων σε επόμενο μη προηγουμενο post:
https://euroelectron.blogspot.com/2019/05/how-does-amplifier-in-class-operate.html
https://euroelectron.blogspot.com/2019/05/blog-post_26.html
Αναφορές:
Sound Picture Recording and Reproducing Characteristics - D. P. Lowe, K. F. Morgan - Journal of the Society of Motion Picture Engineers
Applied Electronics - T. S. Gray - MIT
Tubes vs Transistors (vs op amps), Is there an audible difference? - Russel O. Hamm - JAES
PS
Τι ειναι σωληνες ηλεκρονιων και πως γινεται να κινούνται ηλεκτονια μεςα τους;
Εχει αφαιρεθεί ο αέρας απο μια κυλινδρική διάταξη πχ απο γυαλί. Ενα ηλεκτρόδιο που λέγεται κάθοδος εχει θερμανθεί σε μεγαλη θερμοκρασία απο μια τάση συνδεμένη με κοντινά νήματα. Τα ηλεκτρόνια μεςα στην κάθοδο αποκτούν αρκετή κινητική ενέργεια και φεύγουν απο την κάθοδο οπως οταν βράζει νερό. Σε ενα άλλο ηλεκτρόδιο που λέγεται άνοδος έχουν αφαιρεθεί ηλεκτρόνια απο μια εξωτερικά συνδεμένη τάση. Η θετική άνοδος απο πλεόνασμα πρωτονίων έλκει τα ηλεκτρόνια. Μεταξύ της διαδρομής υπαρχει ενα άλλο ηλεκτρόδιο, συρμάτινο πλέγμα μεςα απο το οποιο μπορούν να περάσουν τα ηλεκτρόνια. Η κάθοδος ειναι και αυτη λιγο θετική αφου εχει χάσει ηλεκτρόνια. Ετςι το πλέγμα ειναι πιο αρνητικο απο την κάθοδο και τα επιβραδύνει. Οπως και να εχει αν μεταβάλλουμε εξωτερικά την ταση του πλεγματος, μεταβάλλουμε σημαντικά το ρευμα ανόδου. Αυτο ειναι ενίσχυση. Στέλνουμε ηλεκτρόνια που χορευουν με το ρυθμο της μουςικης στο πλέγμα ελέγχου και περνούμε τις παλινδρομικες κινήσεις του χορού μεγενθυμενες η ενισχυμένες στην άνοδο.
Πηγη:
Operating Features of the Audion - E. H. Armstrong
How does an electron tube amplifier operate
As with possibly many things in life there are only a handful of persons on the planet who know.
On the subject of electron tubes one of the very few who understood how they operate is the inventor of FM radio, Edwin Armstrong. Particularly on the matter of inserting an unconnected grid between cathode and anode and observing anode current to dramatically decrease. [Armstrong]
So this is possibly the best ever paper written on our planet on how electron tubes operate:
In older times the amplifying electron tube was called Audion, invented by Lee De Forest.
Reference:
Operating Features of the Audion - E. H. Armstrong
How does an amplifier in class A operate?
The continuous flow of electrons (electric current) is modulated by the incoming signal.
Like rotating the tap of water a few times until water flows adequately (this is a bias point) and then turning your hand clockwise anti clockwise following the input signal to be amplified. For example at a rate of 440 times per second clockwise anticlockwise clockwise if the input signal were 440Hz.
The grid of an electron tube behaves like a valve of flow. See other posts.
Similar arguments apply to the base of a transistor or the gate of a FET.
Power supply is the electric field potential difference creating the contineous electron flow, presure difference in the case of water flow.
Further reading:
Applied Electronics - T. S. Gray - MIT
Electronics - Neil Storey
A practical introduction to electronic circuits - Martin Hartley Jones
Reading electron tube datasheets...
is a bit like being the HR reading CVs.
(At your risk, take all safety precautions when working with any voltage or current).
For example the WE417 (5842) looks like a promising candidate for a one electron tube power amplifier operating in class A (electrons flowing all the time).
https://frank.pocnet.net/sheets/185/5/5842.pdf
Very low plate output impedance.
How would it sound at 70V, 10mA driving the linoleum Pleiades Auratone 5C type near field monitoring fullrange speaker with Tesla 5in drive unit?
Can insects dance?
We know from the work of [Martin Lindauer] that bees dance to show the way for good pollen to other bees.
Today while the song
To have and not to hold - Madoona
was playing through Pleiades 2N3055 amplifier and
Linoleum Pleiades Auratone 5C type monitoring speaker
it was observed by chance that the little fly inside the room was changing velocity (direction of travel) most often at downbeat. Strange.
To Have and not to Hold is a great song. It seems great too for such observations.
Reference:
Communication among social bees - Martin Lindauer
Speaker for shagging
It can't possibly be 2 loudspeakers.
It would be too confusing while moving around in the room.
One sounds nice. Like radio.
Tubes vs Ttansistors or is it just active component count?
Today a single ended PCL86 power amplifier was connected to the linoleum Pleiades Auratone 5C type monitoring small cube speaker.
Sound was worse than expected.
Treble was great.
Mid was reasonant.
Bass left something to be desired.
Then the speaker was carried to the smaller reverb room and played with the one transistor Pleiades 2N3055 power amp.
The sound is warm, natural, extended in bass, great mid, great treble.
Could it be that it does not matter if it is transistor or electron tube?
Could it be that what matters is the simplicity of the circuit or in better words the active device component count? Or total component count including passive, active components?
Yes the single ended PCL86 is pentode output, there is a triode driving it. There is an output transformer giving together with electron tube output impedance a -3dB point at the left side of the spectrum.
The Pleiades 2N3055 is single stage direct coupled ie frequency response of amp goes down to 0Hz.
Having said that, the Heathkit AA-32 sounds very nice too although it has more than one electron tubes in the signal path.
Pleiades linoleum speaker as room bass absorbers
While carrying the linoleum Pleiades Auratone 5C cobe monitoring speaker from one room to the other...
It was holded almost like a baby and while a low mid sounded appeared in the room holding hands clearly felt the vibration of the speaker sides.
So a linoleum speaker or any object really absorbs low frequency content as it sympathetically vibrates and its elastomer quality dissipates vibration to heat.
Linoleum objects pickup vibration like antennas. Other objects do too but linoleum can dissipate the energy while it is deformed by vibration from sound.
At the same time it can act as a diffuser due to its shape.
So Pleiades linoleum pyramid speakers will not only possibly sound good but upgrade the acoustics of the room at the same time.
Triangle base pyramids for speakers is an idea of Vicky.
PCL86 single ended amplifier to linoleum Pleiades Auratone 5C type speaker
Not impressive sound.
Just a Pleiades 2N3055 one transistor amplifier sounds so better
Signal path:
(To have and not to hold - Madonna) - Sony Walkman CD player, one channel - Pleiades PCL86 single ended amplifier with Hammond 1626 output transformer - linoleum Pleiades Auratone 5C type cube monitoring speaker with Tessla 5in drive unit - big room
Very nice treble, somewhat deep bass but somewhat harsh and reasonant midrange.
Then the Zeiss Ikon typ:31-06
Similar
Possible cause:
High output impedance of this pentode output stage amplifier with no negative feedback?
A brilliant DATABOOK for electron tubes, RADIO TUBES
Radio Tubes - E. Aisberg, L. Gaudilat, R. Deschepper
This brilliant book has a lovely schematic for each electron tube. Most schematics are in class A ie electrons flowing all the time.
At your risk.
Take all lifesaving safety precautions when any voltage or current is involved.
Hammond transformer 1626
This output transformer had been bought about 20 years ago for making a single ended PCL86 class A (electrons flowing all the time). This is the first electron tube amplifier made up at Pleiades lab.
Schematic had been found on the French lovely book Radio Tubes - E. Aisberg, L. Gaudillat, R. Deschepper data book. The book had been found left at the shelves of a bookshop in the Athens city center. The bookshop was kind of inside a block of flats. What a nice day. This book has a schematic for every electron tube.
Sound is great. It is used for amplifying a WLM organ and feeding an open back fullrange speaker hanged from ceiling and rotated (at your risk). Pleiades Leslie speaker.
This is how the organ sounds. Room had been untreated at that time.
https://m.youtube.com/watch?v=Bmd4NvtCf3g#fauxfullscreen
Today inductance of primary and secondary of the Hammond 1626 output transformer was measured:
14H
11mH
Time or money
It was about 20 years ago.
Engineering electronics students at Warwick university were attending the lecture physical electronics by proffesor Parker.
There was on the green board some equation relating temperature and what happens inside a semiconductor.
The electrons have some kinetic energy so that the temperature is such and such. But the proffesor paused and asked all the students where is this energy coming from so that a semiconductor can be at room temperature for example.
About 10 minutes passed, everyone replied yet no one got the answer correct.
Proffesor Parker had to give the answer.
The sun.
And now on the title of this post.
Energy must be a first notion, cannot be defined. Perhaps like time.
Other first notions can be in geometry, a point, a line. They are prime notions. They can't be defined. But there are axioms that help us understand them. Axioms are sentences taken to be true. For example, from 2 points in space one and only one line passes through.
Getting back to the sun. If some amount of energy is sent in one second to earth, about the same energy much be sent in the next second etc.
We don't know what energy is. But power is defined as energy per unit time. Or in mathematical terms Power is the first derivative of Energy with respect to time. Or the slope at any point if we plot the graph: energy versus time.
Rearranging Energy is Power times Time, E = P x time or E=Pt
The sun generously gives to earth in a sunny day 1000 Watts per square meter. Or 1000Joules of energy per second per square meter.
Every square meter gets 1000 more Joules every second.
Every square meter becomes richer by 1000Joules more every second.
Time is money.
Money is energy. Perhaps this is why this blog os called euroelectron.
The energy from the sun is free.
Saturday, May 25, 2019
Imaginary manufacturing
Happening inside head only.
No workers to exploit.
No trade union strikes.
No expenses.
No visits off or online to the tax office.
No customer complaints.
No lawyers.
No marketing.
No PR department.
No bank off or online visit.
No bills, no pills.
No boss, no buss as this song by Morrissay says.
Free, Time, precious time left to go to the beach which is free anyway.
Linoleum Pleiades pyramid speaker with solar panels
While thinking whether little kid Ionas would like one of these speakers as a present...
One scenario is passive speaker connected directly to headphone out.
Other scenario is with inside it a Pleiades 2N3055 one transistor amplifier in class A (electrons flowing all the time).
This means quite heavy power consumption so...
One side of the triangular pyramid (triangular pyramid is a Vicky's idea) may have the drive unit. Side 2 and 3 may have each a monocrystaline small solar panel.
Internal batteries in Bulgin battery holders could be slowly charged in real time. Fuses for safety etc.
The active speaker could be also used as a pyramid fast battery charger if left under the sun.
Photons from sun creating photoelectrons (emmited electrons from the photovoltaic surface). The waken up electrons by their friends photons arriving from the sun get to work storing themselves to batteries or flowing all the time through the amplifier operating in class A.
2 sides of the pyramid are convenient for following up the sun trajectory through the day.
The first linoleum Pleiades pyramid monitoring speaker with possibly be in red (Tarkett linoleum Etrusco single color series). The color code is nice as it is a red combination with black drive unit, black solar panels. Just 2 colors.
How would the WE417A 5842 electron tube sound as a single ended power amplifier?
At your risk. Take all safety precautions when working with any voltage, current.
This is the datasheet:
https://frank.pocnet.net/sheets/185/5/5842.pdf
Plate (internal output) impedance can be of the order of 2KΩ.
How would it sound with an impedance matching transformer feeding a linoleum Pleiades fullrange speaker? For example the linoleum Pleiades Auratone 5C type or a linoleum Pleiades triangular pyramid speaker?
Would it also operate at say 50V with Pleiades bias with a very high megohm resistor from anode to grid, cathode grounded? Or cathode grounded, open grid?
Since it has relatively high μ (amplification factor), would it work without an input transformer?
This can also be seen from the anode current vs anode voltage curves with grid voltage as a parameter. Small excursions of grid voltage are needed for full output swing.
The idea behind using this electron tube is creating an impedance match amp for maximum power transfer, operating in class A (electrons flowing all the time). Even at 2W plate dissipation, ie 1W max output it should sound very loud, big, deep bass with an output transformer of adequate primary inductance.
A similar argument should apply to the use of an E88CC (2.6KΩ plate resistance) as a 2 channel power amplifier. Grid excursion voltage needed is greater.
https://frank.pocnet.net/sheets/190/e/E88CC.pdf
Playing with capacitors, inductors, resistors
https://m.youtube.com/watch?v=_5W0hAUdBks
Straight wire should produce the fullrange sound.
Neodymium small speakers
So far great sound including nice bass, treble and midrange has been achieved with the linoleum Pleiades Auratone 5C type speakers with Tesal TVM ARX-130-20/4 drive units.
Frequency response is plus or minus 3dB from 100Hz to 14KHz. See previous posts.
While looking for small neodymium drive units these are some of the search results:
https://m.youtube.com/watch?v=H-WMOtNG-k4#fauxfullscreen
https://www.aliexpress.com/item/2PCS-New-Neodymium-Magnet-8ohm-10W-Full-Range-Audio-Speaker-Loudspeaker/32751696993.html
https://m.youtube.com/watch?v=H-WMOtNG-k4
https://m.youtube.com/watch?v=OQ8Q0-KBPcQ
https://m.youtube.com/watch?v=kn1fHTIpkwk
An inexpensive example seen on eBay shows great impedance variation with respect to frequency
https://www.ebay.com/itm/2pcs-57mm-8Ohm-8-10W-Haut-parleur-audio-Haut-parleur-carre-Neodymium-BA/273588148839?hash=item3fb31fda67:g:ABkAAOSwOuRZsPrv
How would linoleum Pleiades baby triangle pyramids sound like with such drivers driven by just one 2N3055 Pleiades 2N3055 power amp?
The pyramid should vibrate as a whole creating great bass at small excusions thereby reducing the Doppler effect.
For the Doppler effect on speakers see James Moir papers.
How to create a triangular pyramid for a monitoring speaker
At your risk. Take all safety precautions.
For example using linoleum as the pyramid material and a fullrange speaker.
See also linoleum Pleiades speakers.
Vicky gave the idea of making a triangle base pyramid as a speaker enclosure.
A tetrahedron pyramid must be a great idea since it only needs 3 sides to be joined if created from a net, see Wikipedia on tetrahedron.
A tetrahedron example.
Using a 5in speaker.
A 14in radius circle should be adequate, drawn on a nice colored linoleum sheet. For example Tarkett Etrusco series.
Then the compass radius is reduced until the circle circumference can be divided to 3 equal parts.
The 3 points then define an equilateral triangle.
The triangle is drawn.
Then the half points on each side are found using the well known compass method of finding the half of a line segment.
3 more points are defined.
The smaller triangle is drawn.
Linoleum is cut on the long sides and just somewhat deeply engraved on the smaller ones.
The centre triangle can be the face of the speaker. Which is convenient for 2 reasons:
1 centre already exists from part 1
2 it is the strongest triangle as its sides are not cut, just bent.
Having said the above. Asymetriy ie not very accurate production may be better for sound.
Method 2.
A great nice and strong equilateral triple is created with small holes at the points defining the triagle. Just a ruler and a compass is needed. See next post.
These points are engraved on linoleum by a compass etc. Then the triple is rotated like a cat keeping these 2 points. Similarly repeated for 3 more triangles around the central one.
Pyramid is ready by just bending the sides of the inner equilateral triangle.
Such tetrahedron pyramids should be much easier to make for a linoleum Pleiades monitoring speaker than a cube Auratone 5C type shape. How would they sound?
Perhaps it is best if 3 drive units are available to do the following test:
Carefully hanging the first drive unit on its own.
Then a speaker with the whole triagle shape as a baffle.
Then a drive unit inside the pyramid.
Wikipedia pages possibly worth creating
A page on:
Auratone monitoring 5C cube speakers.
The inventor Jack Wilson.
Ortofon timeline history. Different models of cartridges. Or expanding the already existing article.
AKG C12
(Neumann U47 already exists (perhaps adding to it the BBC report, schematic))
Fostex flat ribbon microphones such as M88RP, or expanding the Fostex article
Anode to grid bias for low voltage electron tube operation.
(Elements of timeline and patents can be found in an older euroelectron post.
Studio EMI Columbia Athens
Areteos, Kanelopoulos, Giannakopoulos, Konstantopoulos etc.
Sound engineers in time order of the EMI Columbia studio in Athens.
Studio EMI Italiana.
One transistor or one electron tube amplifiers.
Wikipedia has a nice article on class A amplifiers (electrons flowing all the time) included at article Amplifier, amplifier classes.
https://en.m.wikipedia.org/wiki/Amplifier
https://en.m.wikipedia.org/wiki/Power_amplifier_classes
Friday, May 24, 2019
How to change the stylus of the Dual 505-1 record player
At your risk. Take all safety precautions. Disconnect mains etc.
Take you time and be very very gentle.
The particular Dual record player is a 505-1.
https://euroelectron.blogspot.com/2019/05/the-dual-505-1-record-player-in-pleiades.html
The cartridge found on it is an Ortofon TKS 49s.
The study's found on it is Ortofon DN149S.
The stylus cannot be removed if the cartridge is not removed. There is a protection mechanism.
How the cartridge is removed can be seen on this YouTube video:
Dual CS505 - how to remove the headshell and replace the stylus - GB audio
https://m.youtube.com/watch?v=YP0j9P0t24s
Make sure the small screw on top is lifted a lot.
Once the cartridge had been removed the stylus could be just removed by an easy sliding action along its length.
There was a groove found on the cartridge body. This indicates that some styli make have a protruding element that mates.
The DN149S stylus found does not have such thing and can be inserted too. Length of the plastic body of this stylus is approximately 1.7cm
Sound is amazing.
The Dual 505-1 record player in Pleiades
Serial number: 170058
It had been found abandoned on the pavement.
No dust cover.
Turntable rotated but there was smoke and a bad odor after some seconds.
Motor bearing had been lubricated. Smoke had stopped.
Belt was very slack.
The one that arrived by post never quite worked properly while changing from (33+1/3)rpm to 45rpm.
Then one rubber belt of less width had been bought from a local electronic spares shop which did the job even worse. Many hours were spent with different diameters. Angular velocity would not change. It was abandoned.
After a few years it was dusted off again for a listen. It worked almost immediatly by removing the belt and replacing it with itself. Angular velocity now changes! Time heals.
It has an Ortofon moving magnet cartridge type TKS 49S. The stylus says DN149S. See next post.
Listening tests were done on various minimum electron components systems, see this week's posts.
Frequency response and smoothness is so extended on both extremes of perceived by brain spectrum, it is amazing.
Sends digital to the cleaners.
Testing other transistors on Pleiades 2N3055 one transistor power amplifier
This is the schematic used:
https://euroelectron.blogspot.com/2019/05/pleiades-one-transistor-emitter.html
BD243 was tried
2N2218 was tried
RCA 2N3053 was tied too
Signal path, setup:
(Ray of Light - Madonna, CD) - Sony CD Walkman, line out mono bridged - Pleiades one transistor power amplifier - 4Ω linoleum Pleiades Auratone 5C type speaker with 4Ω Tesla 5in TVM ARX-130-20/4 drive unit - small reverberant room
They sound nice but 2N3055 is more sensitive for given CD Walkman line out
2N3055 sounds great even at <500mA collector current.
Looking at the RCA datasheet for 2N3055 the gain bandwidth product at 1MHz is max (1.6MHz) at 100mA collector current. At 500mA it is 1.3MHz.
Later addition:
The BD139 was tried after a few days. Wow! See future post:
https://euroelectron.blogspot.com/2019/05/auditioning-bd139-transistor-on.html
Reference:
RCA Solid State DATABOOK Series
SSD-204A
Power Transistors
Selection Guide
Data
Application Notes
1973
Thursday, May 23, 2019
Terminology of triangle pyramid
https://study.com/academy/lesson/what-is-a-triangle-pyramid-definition-formula.html
Also:
https://en.m.wikipedia.org/wiki/Tetrahedron
How would fullrange speakers made of linoleum at this shape sound like?
Vicky's idea is a triangular pyramid speaker.
A nice full (tube,transistor) analog system sounds at least 2 octaves below or above
(tube, transistor) obviously with Low negative feedback. Ie few components.
See today's posts including yesterday's with Sennheiser HD580 headphones.
Creating very deep bass from baffle speakers
This was realized almost by accident today.
At your risk.
At Pleiades Lab usually elastomer membrane absorbers behing painting canvas using canvas frames are hanged from ceiling and spaced from walls for bass reverberation absorption (see older posts).
Picture Hanging Systems UK materials are used like on museums for picture exhibition.
Recently a Zeiss Ikon baffle speaker had been hanged.
And today a nearby Heithkit electron tube amplifier on the floor had been connected to it. See today's posts.
Bass is very deep, jaw dropping deep.
Subjectively it sounds like going down almost flat to 40Hz.
Yet the baffle size is only 20in by 20in and the high class drive unit is only 7in, (6in paper membrane).
This may be explained by:
The gentle (only 6dB per octave) bass drop of baffle speakers compared to 12dB per octave on closed infinite baffle ones and 24dB per octave of bass reflex or vented enclosures.
Further listening and touching tests revealed that the wooden baffle vibrates at bass frequencies. A large area vibrating creates acoustic impedance match. Bass needs a lot of air to be moved and a large area does this.
Wood panel vibrates as the mechanical wave inside it travels from drive unit to edges and is reflected back due to impedance mismatch at the free boundaries of wood. Just like drums or even better cymbals. Or water waves reflected at the edges of a swimming pool.
The baffle wood panel becomes like a small piano soundboard.
The 7in speaker somewhat becomes a 20in x 20in speaker which is a huge speaker.
How would linoleum baffle speakers sound carefully hanged from ceiling?
Would they dissipate resonances by elastomer absorption?
A great electron tube record reproduction setup
All electron tube from vinyl record to loudspeaker
45rpm record, License to Kill, James Bond maxi single, side B orchestral, Pam, Michael Kamen - Dual 505-1 turntable with its Ortofon cartridge - Heathkit AA-32 integrated electron tube amplifier - Zeis Ikon baffle 7in fullrange speaker
Just tried on one channel using one speaker.
A nice sounding analog electron tube system such as this sounds many octaves extended to bass or treble
In other words may send to tea digital reproduction
The linoleum Auratone 5C type speaker sounded very nice too. Amazing acoustic guitar, strings etc.
Amazing sounding baffle speaker, Zeiss Ikon typ: 31-06
Setup:
The Power of Goodbuy - Madonna - Sony CD Walkman line out - Heatkit AA-32 electron tube amplifier - one Zeiss Ikon 7in fullrange speaker on baffle - large room
Speaker magnet says Zeiss Ikon Magnetfabrik DEW DORTMUND
Baffle size is 20in x 20in. Baffle says ZEISS IKON Kabinenlautsprecher Typ:31-06
Amazing sound. So deeeeeep bass (baffles only drop at 6dB per octave, ie gentle slope) and great treble. Smooth midrange.
So boxiness bassmud coloration as there is no $&@&$ box.
Then the linoleum Pleiades Auratone 5C type speaker was connected. It sounded smaller, less loud with some bass, focused but not as clear. This cube speaker sounds better with the Pleiades 2N3055 one transistor single ended class A (electrons flowing all the time) low power amp.
Linn Sondek turntable, Altec amplifiers, RCA, Altec horn loaded speakers
Live Sound Designs
https://m.youtube.com/watch?v=CVaazHrDp-w#fauxfullscreen
Ο μουσικός καθρέπτης
Σ'αυτο το παραμυθι η Λουσι η γάτα απο την Αγγλία αποκτάει μικρα γατάκια.
Αμέσως τα εκπαιδεύει βάζοντας τα να πατανε με τα ποδαράκια τους αντίστοιχα πλήκτρα του πιάνου ωςτε ο εγκεφαλος τους να μάθει να τα αναγνωρίζει οπως και να ακουει καθε νότα οπως μαθαίνονται οι λέξεις σε καθε γλώσσα.
Τα γατάκια μετα μπορούν να αναγνωρίζουν την καθε νοτα χωρις παρτιτούρα οπως λειτουργει ο προφορικός λόγος. Το ίδιο λοιπόν για καθε μουσικο διάστημα.
Ετςι τα γατάκια οπου βρεθούν μπορούν, ακουγοντας μουςικη απο οποιαδήποτε πηγη, να εκπαιδεύονται στην αρμονία.
Έχουν και ενα κλαβιε για να κανουν δοκιμές στις διάφορες μελωδίες που τους αρέσουν να ακούνε στο YouTube.
Οταν κουραστούν κοιμούνται πανω του ζεςτα αγκαλιασμένα.
Ονειρεύονται μελωδίες και αφου ξυπνήσουν προσπαθούν να τις παίξουν.
Μια μέρα πανε στη μουςικη βιβλιοθήκη και βρίσουν τυχαία στο τέλος του βιβλιου βιογραφίας του Μπαχ απο τον Σπητα το εγχειριδιο του Μπαχ (Bach Bass Rules) για την μουςικη (κλασική, ποπ, τζαζ, οποιουδήποτε είδους).
Αμέσως το καθε γατάκι σκαρφαλώνει πανω στο άλλο για να το φωτοτυπησουν και να το πάρουν μαζι τους.
Το παραμυθι εχει αναφορα στα
Bach Bass Rules
Harmony - Piston
Canelina in musicland
Fairy tale inspired from Gamov fairytales in physics.
Canelina the cat attends an online YouTube lecture a well known university. Music and mathematics belong to the faculty of arts.
The lecture subject is the musical intervals.
Canelina doses off while the lecturer explains.
She is transferred to musicland where the citizens are alive and kicking musical intervals.
Each interval kindly presents itself to princess cat Canelina. Accompanng music of course begins with each self introduced interval...
The fairy tale has references on
Bach Bass Rules PDF
Harmony - Piston
Qui Tollis - Bach (begining wity interval of 6th major)
Un homme et une femme - Lai ( begining with interval of major 7th)
Just Hold Me - Matia Mena (begining with intervals of minor 3rd with interval of major 9th)
Close to you - Carpenters (begining with interval of major 3rd with interval of major 9th)
Music Possibly from Pleiades - renewablemusic (beginning with interval of (perfect) 4th)
Wednesday, May 22, 2019
A nice big shop for buying Tarkett linoleum in Athens
www.plastino.gr
Near Ηράκλειο railway station.
Manager Georgios Vitsaksakis is very helpful.
A world class analogue vinyl record playback setup without having to spend a fortune
Nice and simple:
Signal path:
a nice 45 rpm 12in record - Dual 505 turntable with it's Ortofon moving magnet cartridge - Realistic 32-1101A battery powered disco mixer - Sennheiser HD580
45 rpm record used is:
Side B - PAM - Michael Kamen - Michael Kamen and the National Philharmonic Orchestra - Maxi Single Glahys Knight sings Licence to Kill 007 - made in England
Who can say but it sends to the cleaners (sends for tea) digital playback.
Cube of other sumetric shape in acoustics
Almost any textbook on acoustics would quickly dismiss a symmetrical shape such as a cube for a recording studio or a loudspeaker enclosure.
Yet possibly the most successful in sound quality recording studio worldwide (CBS 38th street church in New York) must had been 100ft x 100ft x 100ft [Laico interview AES, YouTube].
And possibly the most successful monitoring speakers, the Auratone 5C was 6.5in x 6.5in x (5+3/4)in
How would a (symetric) triage based pyramid (Vicky's idea) with equal sides sound like? Such a shape is called tetrahedron.
https://www.dkfindout.com/us/math/geometry/triangle-based-pyramid/
How would it sound with a fullrange speaker and enclosure made from 2.5mm thickness linoleum?
How would nice linoleum colored pyramid monitoring speakers look like?
They should also be easier to make than cubes. Only major tool needed could be a large compass to draw triangles with equal sides, one next to the other:
https://www.dkfindout.com/us/math/geometry/triangle-based-pyramid/
Cable could just come of from the back bottom like a cat' s tail.
Sides can be joined with thermal glue or welding rids of same or other color etc.
How would small linoleum ones look or sound like, baby Pleiades pyramids?
How would linoleum Pleiades Auratone 5C type cube monitoring speaker with Tesla 5in TVM ARX 130-20/4 drive unit compare with a tetrahedron version? The cube with Tesla speaker and linoleum gives + or - 3dB from 100Hz to 14KHz, excellent transient quality as well.
Can a 1 transistor amplifier fit inside a small pyramid? For example an active monitoring speaker or a small external amplifier inside a pyramid. Everything including Bulgin battery holder etc and suitable fuse in series for safety. Would linoleum be safe to use?
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