Friday, November 30, 2018
Pleiades R,C highpass filter with AKG D112
Signal path:
Male singing voice at 1-4 in - AKG D112 - Pleiades R,C filter - Sony TC-D5 Pro - Sennheiser HD580
The Pleiades R,C is a gentle slope low cut or high pass made with a series capacitor shunted by a resistor. A 50K linear variable resitor was used and a Heathkit capacitor box.
First impression was that just a C may sound nice.
Second impression was that an R is needed too.
Third impression was that R,L in shunt sounds better, see Pleiades R,L filters.
Nevertheless 2 values that sounded nice with nice treble are 47nF, 42KΩ.
Other interesting combinations.
68nF,22KΩ
68nF,οοΩ (only C)
47nF,26.7KΩ (this possibly sounds better, less bass heavy than 130Ω,40mH)
This may be placed inside an XLR to XLR Neutrik modules barrel female to male adaptor. 2 capacitors and 2 resistors of the corect value may be used for better balanced operation.
Thursday, November 29, 2018
Finos Film
According to initial information by Spiros Anaktoridis they were possibly recording on Revox electron tube reel to reel.
Mixing (adding is the correct word in electronic engineering) console with electron tubes and inductor passive EQs was designed and made by electronic engineer Mikes Psalidas. He had made another one for Vangelis. He was very carefuly studying flat frequency response from producers brain to listener's brain from publications such as Cinema Engineering, Elements of Sound Recording - Frayne, Wolfe. Finos had asked his help on improving the sound quality of movies in Hellas. Mikes Psalidas suggested they subscribe to the Journal of the Socienty of Motion Picture Engineers. And they did. See previous posts.
Μες αυτη τη βάρκα - Hatzidakis, Hatzidakis, sung by Vougiouklaki
https://m.youtube.com/watch?v=Y2eT4mZ0Ohs#fauxfullscreen
More information on the demo sung by Nana Mouskouri and lyrics:
http://www.stixoi.info/stixoi.php?info=Lyrics&act=details&song_id=6661
Wednesday, November 28, 2018
AKG D112 with Cinema Engineering 4031-B or Pleiades (130Ω,40mH)
The AKG D112 had been bought through eBay as it has a very similar frequency response curve to the Neumann U47. The idea was to connect it ie its moving coil element to a step up transformer and then to the grid of an electron tube powered by battery, see Pleiades V6. Underheated electron emitting cathode like the VF14 electron tube in Neumann U47.
Of course proximity effect compensation, Fletcher Munson curves compensation and voice effort effect compensation is needed to reduce the bass heaviness and archive a flat frequency response from singer's vocal chords to listener's brain [Lowe, Morgan].
This post focuses on D112 and wave filters only. Mic is connected to passive wave filter. The output of the wave filter is then connected to a standard preamp. So no mic booster amp such as Pleides V6 is used on these experiments.
Signal path:
Male singing voice at 1-5 in - AKG D112 - passive filter - Sony TC-D5 Pro at XLR mic in - Sennehsiser HD580
A phase inverting XLR to XLR is also used before Sony as for some reason the particular one used phase inverts.
1 The D112 is connected directly to Sony TC-D5 Pro. Very bass heavy sound.
2 The Cinema Eng passive EQ is connected between the two. At -10 for Low Frequency (100Hz?) setting the sound is remarkably nice. Boosting a bit at 3KHz makes presence even better. Unfortunately there is hiss as the EQ has insertion loss (14dB?) [Tremaine]. It should be connected after a mic booster front end amp or a preamp.
3 The Pleiades (130Ω,40mH) gentle slope low cut passive wave filter is connected between mic and preamp. Just a 130Ω resistor in series with 40mH. The resultant connected in parallel ie to pins 2.3 inside a Neutrik Module XLR to XLR barrel. The sound is very nice and big. There is almost no hiss as the Pleiads filter just subtracts what is not wanted. Sound could be further improved by optimizing the R, L values. A variable box should ideally be built. Series C in parallel with variable R should be tried too as an alternative to gentle slope low cut.
Later today's addition. By connecting L=85mH and R(330R log pot) with cable clips a combination of 85mH is series with 100Ω sounded very nice and natural with D112 at 3-4in. The 85mH inductor is made by winding a small grey colored Siemens Epcos (Siemens Matshushita) ferrite ring core which fits inside an XLR female to male barrel adapter. The core type should be R 12.5.
Singing together with Yamaha PSS-14 synth strings chord backing, the Pleiades (130Ω,40mH) sounds more edgy, with more bandwidth on both sides of spectrum, with less mid range giving a sense of a smoking singer, while the Pleiades (100Ω,85mH) sounds more clear with more focused midrange while still having treble. Bass frequency spectrum content of voice is natural in both cases. The latter filter has more focused presence. Pehaps with the backing harmony the first example is more suitable as the edginess makes the voice stand out. Another interesting R value is 73Ω. More experiments are needed, for example varying R,L parameters while singing to a backing track. See also Pleiades R,C filter on tomorrow's post.
references:
Sound picture recording and reproducing characteristics - D. P. Lowe, K. F. Morgan - JSMPE
Audio Cyclopedia - Howard M. TremaIne
Freedom is...
having the choice to do otherwise
From Vangelis interview quoting a definition of Aristotle
https://www.tovima.gr/2016/09/26/vimagazino/baggelis-papathanasioy-oloi-eimaste-synathroisi-disekatommyriwn-etwn-mnimis/
Extract of Vangelis interview, how music is composed?
Πώς έρχεται η μουσική σε εμάς; «Υπάρχει το εξής. Κάποιος γράφει ένα μουσικό κομμάτι. Μπορεί να το γράφει επειδή το σκέφτηκε, είναι δηλαδή κάτι υποκειμενικό, που μπορεί να είναι και πάρα πολύ ωραίο. Μπορεί να μη σκέφτεται τίποτα. Τότε το γράφει η ίδια μουσική. Χρησιμοποιεί, δηλαδή, η μουσική κάποιον ή κάποια προκειμένου να γραφτεί».
How does music come to us?
"Somebody records a musical composition. It may be recorded due to thought, something subjective, it may be very nice. Somebody may not think of anything. It is then music recording itself. Music uses a man or a woman so that she is recorded."
Rough translation from a Vangelis interview quote.
Source:
Interview in BHμαγκαζίνο.
https://www.tovima.gr/2016/09/26/vimagazino/baggelis-papathanasioy-oloi-eimaste-synathroisi-disekatommyriwn-etwn-mnimis/
Know something? I know your melody - Vangelis
"Ξερεις κατι, ξέρω τη μελωδια σου"
"You know something, I know your melody".
This is what Vangelis when a kid was saying to someone he would meet irrespective of age.
They would smile. And would caress his hair.
When you watch nature closely, she would tell you everything. - Vangelis
Source:
Interview of Vangelis:
https://www.tovima.gr/2016/09/26/vimagazino/baggelis-papathanasioy-oloi-eimaste-synathroisi-disekatommyriwn-etwn-mnimis/
Painting is art, music is science - Vangelis
From this nterview of Vangelis:
https://www.recital.gr/2017/03/31/sinentefxi-me-ton-vangeli-papathanasiou/
Another way of measuring subjective equivalent input noise resistance
At your risk. Proctect your hearing.
Short circuiting the input. Listening for hiss. Then increase the terminating input resistor of a just noticeable difference (JND). Measure this terminating resistor.
Since this may corespond to a change of 3dB [Stevens] (doubling of power) this method may give similar results to objective VU meter ewuivant noise resistance measurements [Pearson]?
References:
Sound and Hearing - S S Stevens, Fred Warshopsky - Time science series
Fluctuation noise in Vacuum Tubes - Pearson
Interview of Vangelis
In hellenic language:
https://www.recital.gr/2017/03/31/sinentefxi-me-ton-vangeli-papathanasiou/
and another interview:
https://www.tovima.gr/2016/09/26/vimagazino/baggelis-papathanasioy-oloi-eimaste-synathroisi-disekatommyriwn-etwn-mnimis/
Electronic engineer and director Alfred Hitchcock never won an Oscar award
Same for Charlie Chaplin.
Source:
Interview of Vangelis:
https://www.recital.gr/2017/03/31/sinentefxi-me-ton-vangeli-papathanasiou/
Tuesday, November 27, 2018
The first few chords of Skyfall - Adele on Bechstein piano
Skyfall - Adele intro played on Bechstein piano
https://m.youtube.com/watch?v=PtMxQNMeT1M
Monday, November 26, 2018
Beyer M55 types
An excellent sounding omnidirectional moving coil microphone.
There are many variations according to period of manufacture.
This is a very rough guide.
Older types are chrome with grey cable and dual impedance. Typically the low Z pin measures 180Ω, hi Z around 40-80? KΩ. For some strange reason some may be inverting, so phase attention is required unless one may like to use the noise canceling effect of 2 omnis out of phase, see Lou Bouroughs microphone book.
Newer types are black. Impedance usualy 470Ω.
There are also chrome ones with black cable. Dual mpedance but low Z was measured 470Ω.
A chrome one was found which is 500Ω.
They all sound excellent with no bass heaviness and nice unhyped treble. Great midrange. No s problems. No pop problems. No handling noise.
They sound great connected to Sony TC-D5 Pro, to Uher 4200 report, to a Pleiades V4 front end battery powered electron type amplifier.
If analog tape can record the hiss of a preamplifier...
this possibly means that it can record the thermal motion of electrons.
Sunday, November 25, 2018
Girls in the Sun, the full movie
Featuring music recorded at Columbia EMI studios Athens
https://m.youtube.com/watch?v=Vbc0BklxgUM#fauxfullscreen
Sending line out to Sony TC-D5 PRO XLR mic in
At your risk.
This may be done by a 50KΩ or more series resistor and a 330Ω shunt resitor.
A simple potential divider that may have an output impedance of nearly 330Ω simulating the output impedance of a microphone.
Low noise experiments on Sony TC-D5 Pro
At your risk. Protect your ears.
A multi turn wire wound potentiometer was connected at the XLR input as a variable resistor.
Limiter switch is on.
When resitor is at 0Ω the noise is lower and rec level may carefuly be increased until noise is heard.
Then the multi turn potentiometer is careful turned until subjective noise becomes double.
The measured value of the resitor was 327Ω, giving a measure of equivalent subjective input noise resistance.
Simulating a very low music level 300Ω microphone output for low noise preamplifier tests
At your risk. Protect your ears.
This was done by connecting a series 10MΩ resistor to line out of a Sony Walkman CD player and then a 330Ω shunt resistor.
It may be better to use a 200Ω wire wound resistor as many mics have such output impedance.
Then another such attenuator was connected in cascade.
(A very important source of noise is thermal noise. Ie agitating electrons in a conductor due to thermal energy which we all receive from the sun). Hiss. See also Johnson thermal noise.
Signal path:
ABBA Voulez Vous CD - Sony CD Walkman line out - 10MΩ, 330Ω potential devider - 10MΩ, 330Ω potential devider - (in fact another one may be needed) - Sony TC-D5 Pro, limiter on - Sennheiser HD580
After the second attenuator or potential devider music is buried in noise as if listening to a very distant radio station. The noise heard should be the 330Ω thermal noise only on a good preamplifier.
When music is so low that it is almost inaudible adding a Western Electric 1:2 step up transformer stepping up the impedance to 4x ie 1200Ω makes music clearly audible.
This may show that the signal to noise ratio of Sony TC-D5 can be improved by a good quality passive or active mic booster amplifier. Examples are a good low turn ratio transformer or for example a Pleiades V6 electron tube battery powered preamplifier respectively.
And it may also show that when we accuse tape of low noise we may be in fact be acussing
preamplifier noise or thermal noise which has nothing tho do with analog tape itself.
Saturday, November 24, 2018
Annabel, recorded at Columbia EMI Studios Athens
From the movie Κορίτσια στον Ηλιο, (Girls in the Sun).
Annabel - Xarchakos, Papastefanou, Dimitridi
https://m.youtube.com/watch?v=2TybpWiEmwQ#fauxfullscreen
Ray Charles on Bechstein piano
Georgia - Ray Charles
https://m.youtube.com/watch?v=-DFhuE_XeT8#fauxfullscreen
Nice A major 7th
at 0:23
Killing me softly- Frank Sinatra
https://m.youtube.com/watch?v=8tbP3f3i03E#fauxfullscreen
It may sound like a Bb major 7th but it's not. The key is not D minor. It is C# minor.
G sharp played by the violins is prepared by being played once more before the beat when bass becomes A. The chord is A C# E G#.
Further reading:
Bach Bass Rules:
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
Thursday, November 22, 2018
Euroelectron pageviews yesterday
Graph of yesterday's most popular countries among blog viewers
Entry Pageviews
South Korea
16
Greece
9
China
2
United States
2
Germany
1
France
1
Italy
1
Netherlands
1
Russia
1
Wednesday, November 21, 2018
Tuesday, November 20, 2018
Great sound with Shure Unidyne B 515SB
Signal path:
Shure 515SB - Pleiades (130Ω,40mH) - Western Electic D163851 - Sony TC-D5 Pro - Sennheiser HD580
Continuing from a few days ago (see relevant post) test of the made in Mexico mic, this time the made in USA Unidyne B was tested.
The Western Electric transformer (1:2 ratio, 1 Henry to 4 Henries) was tried on both to step up passively the signal and the impedance to 800Ω for driving much hotter the Sony preamp.
The Pleiades gentle slope low cut filter inside a Neutrik module XLR barrel, made of a 130Ω resistor in series with an inductor of 40mH and the total connected across the mic (pins 2 and 3), makes possible the use of the mics at about 1-3in with very clear sound devoid of low frequency heaviness (objective and human brain perception) artifacts.
Including the Western Electic step up transformer made an impressive increase in the body of sound, loudness, as the Sony was now generously driven.
Changing from the Mexico version to the USA version the sound got even better. More shinning bright, big and without strain. Excellent midrange and natural bass.
Impressive.
Monday, November 19, 2018
Is chance inspiration?
Maybe sometimes?
Many inventions were made by accident. For example the post-it stickers made from failed glue experiments.
Does it happen to music composing too?
For example, we know the Pink Floyd were playing, jamming for an hour or so E minor to A major while Breathe from Dark Side of the Moin was being developed. Could it be that at some point Roger Waters played C on bass instead of E thereby creating the fabulous sounding C major seventh chord, C E G B? It's so nice, let's keep it.
A simple melody could also be made by a keyboard playing the wrong notes.
This is how Semele was created. The keyboard used had been bought from a yard sale for 1 euro. It is so deliberate cheap and toy that it played the wrong notes. Instead of playing C it would play for example F. The nice inspirational keyboard is Soupeb Sound Audio Products model EK-210.
So by chance, this is the melody that came when trying to playi on it.
Semele - public domain: https://m.youtube.com/watch?v=Mu3Cwy_CRNc
Key is D minor so every B is B flat.
Bass code is B then G7 then D then C246 back to B.
Ie BbDF, GBbDF, ADF, ACDF back to begining.
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
A simpler way to listen to deriving the backing track
At your risk.
For example pulling the headphone plug a fraction of a millimeter from the iPad.
The voice, bass and everything else positioned at center disappeares.
What we now listen to is the L-R or R-L signal.
So we can hear in detail reverbs used in a production, backing vocals, strings etc.
For example on Skyfall - Adele Adkins, Paul Epworth
https://m.youtube.com/watch?v=DeumyOzKqgI#fauxfullscreen
We can hear the reverb of the vocal coming a fraction of a second latter, perhaps due to the acoustic path from loudspeaker to microphone inside the Abbey Road echo chamber or pre delay etc.
Sunday, November 18, 2018
Shure 515SD Unidyne B with Pleiades (130Ω,40mH)
Signal path:
Male singing voice at 1-3 in - Shure 515SD Mexico - Pleiades (130Ω,40mH) - Sony TC-D5 Pro - Sennheiser HD580
This combination sounded quite nice. The gentle slope high pass from the series R,L in parallel to voice coil reduced bass heaviness of proximity effect, equal loudness curves, voice effort curves.
See also adding a Western Electric 1:2 step up transformer and including in the test the Shure Unidyne B USA version:
https://euroelectron.blogspot.com/2018/11/great-sound-with-shure-unidyne-b-515sb.html
Saturday, November 17, 2018
A musical break
This song has just been on air by Melodia FM radio station.
It is in 9/8, ie every bar contains 9 (equal time separated) beats. The baglama rhythm section strums at double speed ie 18 strums per measure.
Rough translation of the title is The Unspoken or Indiscribable.
Key is F sharp minor.
Τ' Ανείπωτα - Ζεβουδακης
https://m.youtube.com/watch?v=jL0QV7H7-o0#fauxfullscreen
Some books on movie scoring
Underscore - Frank Skinner
This book was influence on Quinvy Jones and he discovered it while babysitting in the house library. See Quincy Jones interviews.
Sounds and Scores - Henry Mancini
A practical guide to orchestration
Composing for the Cinema - Ennio Moricone, Sergio Miceli
Thursday, November 15, 2018
A world class analog recording signal path
Beyer M55 190Ω L channel
Singing at 3in - - Uher 4200 report - BASF per 638
Beyer M55 540Ω R channel
It took nearly 47 years to get to that synergetic combination but now it just takes 2 minutes to setup by connecting mics and pressing the REC button key.
Consumption less than 3 Watts?
World class sound.
No hiss or noise.
No s or pop problems.
Portability and independence from electrical utility grid.
No need for special acoustics.
Flat frequency response from producer's brain to listener's brain. Perhaps If still a bit bass heavy AKG MI 201-100 or other mics can be tried.
Does not cost millions.
Many mics can be connected in parallel series combinations to get back to 600Ω for multi miking instruments.
Only 3 transistors in class A operation (electrons flowing all the time) from mic to magnetic tape.
Does not need input, output transformers.
Does not need mic booster preamps eg Pleiades V6 etc.
Does not need compression, limiting, de essing.
Does not need a Pultec EQ.
It sparkles like a diamond without the hype.
Pleiades Labs history
Unedited .
The Pleiades labs is possibly a failure.
It took nearly 47 years to find out the obvious. For example that 2 Beyer M55 microphones dirctly connected to an Uher 4200 analog recorder at 7.5ips can produce and record a great natural sound, Witt almost flat frequency response from singer's vocal chords to listener's brain.
Why?
Stupidity is one reason.
Here is a summary of the Pleiades labs history.
1972-1980
The only available recording reproducing equipment were 1 JVC portable cassette radio recorder and a Grundig transistor long wooden console radio and record player.
A new piano, gift by great grandfather Melelaos, become a very important tool for ear training, pleasure and lessons.
An electronic table game called Polycyclomatic allowed connection of electronic components to Germanium transistors for making oscillators or amplifiers (in class A operation).
1980-1990
Reproducing equipment including cassete recorder and record player by Metz.
Electret capsule mics bought, cardioid so resistance controlled diaphragm.
Constructing kits such as HF-65 by Jostykit.
Discovering Pink Floyd and major 7th chords.
1990-2000
A few years at university of Warwick in engineering electronics
Access to anazing books including Electronics - T.S. Gray, Elements of Sound Recording - Frayne, Wolfe, Practical introduction to electronic circuits - Jones, Electronics - Neil Storey, Feynman Lectures in Physics, discussions with Dr. R. Pettifer on noise, Fourier transforms, electromagnetic waves.
Access to many beautiful sounding pianos and to choir singing
Final year project on single ended triode 300B power amplifiers.
Experience at Audio Note UK
Finding by chance the Bach numbered bass composition manual at the appendix of Bach's biography - Spitta at a music library [Bach Bass Rules edited by Schmidt].
Purchasing 2 Grampian ribbon mics and a Ferrograoh series 6 recorder at a NEC? fest.
Back to Ελλας.
It's Internet time.
Pleiades rotating speaker conceived and promptly made. Connected to WLM organ Amelie's by the first Pleiades PCL 86 power amp with Hammond manufacturing company transformers.
Making recordings of rock band with the Grampian mics to Sowter transformers to Ferrograph. Very nice sound.
Access to AKG C12a and C24.
Buying Coles 4038.
Making electron tube mic preamplifiers, Pleiades V -4, -3, -2, -1,
Building Altec electron tube compressor clone after suggestion by Lefteris, then incorporating turbo sounding Singer patent. See previous posts.
2000-2010
At a studio recording 24 track analog.
Mastering from 1/4in tape at Abbey Road studios.
Back to Hellas.
Buying military signal transformers from surplus yards after Lefteris suggestion.
It's eBay time.
Buying the main monitor reference, Sennheiser HD580 sugested by Lefteris. Trying RCA BA-6A limiter. Cinema engineering EQ.
Trying RCA 44 ribbon microphone.
Recording to Philips CD-R ADC modes after suggestion by Panayiotis.
Recapping various Oberheim synths, drum machine, Yamaha DX7ii etc.
By Albert's influence Pleiades tuning conceived, applied to DX7ii, Korg Triton.
Building U47 VF14 amplifoer clone by Leferis suggestion. Buying Sennheiser MD421 suggested by Yiannis.
Making Pleides T1 K116 by Panayiotis influence.
Making Pleiades V1, electrometer tube with AAA battery. Sean Davies sugested electrometer tubes.
Pleiadss electrical utility off grid since 2008.
Buying battery powered Tacam Porta 01, 02, Sony TC-D5 pro, Marantz MD-430.
Adding a coil (Pleiadss filter) in parallel to the low Z capsule of SM58 for low cut and recoding nicely to Sony TC-D5 Pro
2010-
Pleiades Electra 1, 2, 3 one electron tube power amplifiers
Pleiades L microphone filters
Rediscovering that the aim is flat frequency response not from mic to loudspeaker but from producer's brain to listener's brain [Lowe, Morgan]
Rediscovering that low acoustic sound pressure levels can lead to singing in tune [Stevens], [Ramone].
Rediscovery that grid is already negative by cathode emission. A pull up or Pleiadss bias from anode or Vb to grid by a Hugh Megohm resistor makes low noise operation possible at even 3.6V at anode or plate.
Pleiades battery powered electron tube microphone booster preamps V2, V3, V4, V5, V6
Pleiades 2N3053 one transistor power amplifier.
Pleiades R,L gentle low cut microphone filters
Testing as many world class mics from Shure, Elctro-Voice, Sennheiser, Beyer, Paso, Shaub Lorenz
Buying 2 fabulous Uher 4200 report recorders
References:
Sound and Hearing - S. S. Stevens, Fred Warshopsky - Life Science Series
Making Records - Phil Ramone
Bach Bass Eules: https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
Sound Picture Recording and Reproducing Characteristics - D. P. Lowe, K. F. Morgan - Journal of the society of motion picture engineers
The 2 Uher 4200 in Pleiades labs
The one bought last operates on both channels.
The 1st one bought operated only on right channel. A shorted psu decoupling electrolytic capacitor was the cause of one channel not operating. Just one capacitor. Now everything operates fine and it sounds fantastic.
18112112
There was some hum due to cold soldering
Changed capacitor to Frako 100μF 16V GPF after reforming it with a series 1.6MΩ to 15V for 24 hours
No hum
Wednesday, November 14, 2018
Cleaningness in electronics
It seems important.
For example wiping the leads of a component with a tissue moistened in methylated spirit so that it become clean and shiny. Then it can be soldered.
Cleaning mic XLR connectors. With cotton buds and methylated spirit?
Keeping heads of tape recorders clean. With cotton buds and isopropyl alcohol?
Dust and bad connections may be the worst enemy of electronics?
Etc.
Monday, November 12, 2018
A difference between mass media shareholders and mass or public
A mass media channel shareholder may believe in human kindness and trust between people.
Yet the channel transmits insecurity, distrust, phobia etc as insecurity is the best product.
What do the listeners do. Buy insecurity or not?
An example: radio plays a lovely song about trust between 2 in a relationship. The lyric says I believe you no matter what. I believe in you.
Song ends. The DJ comments, no it's a big mistake.
Yet if one had met by chance at a vintage car servicing shop a mass media shareholder, he, she would have advised positively, you should trust people.
Quote from Mike: Insecurity is the best merchandise
Further reading:
Enchiridion - Epictetous - free PDF
Sunday, November 11, 2018
One possible cause of mechanical noise on Uher report 4200
A twisted belt.
Original belts are of triangular cross section.
Placing it straight, crest angle towards the pulleys, reduced mechanical noise substancialy. Preliminary checks showed that wow and flutter did not become worse due to rubber memory effect. Initially there was some static noise (while anti static belt brushes are readjusting). It seems to have disappeared.
If noise persists, the flywheel -motor belt can be rotated 120 degrees or another 120 degrees.
There is also a seller on www.eBay.de selling round cross section belts for the Uher report.
Viewing simultaneously both sides of circuit board
This may be done by viewing component side while stronger light strikes the track side.
The shadows of the tracks will be projected on the component side.
This has proved useful while fault tracing on a Uher 4200 report where 1 channel is not working. It seems a rail decoupling capacitor capacitor has become a short circuit.
Soft starting unused for long electronic equipment
At your risk.
Soft starting electronic equipment that had not been used for long may be a good idea.
Switching On and Off momentarily the first time and gradually give more On time.
This gives the electrolytic capacitors chance to recover or reform.
See also post on reforming old or unused electrolytic capacitors.
Saturday, November 10, 2018
Πως γινεται να πετάγεται μπροστά η φωνη;
Σε ηχογραφήσεις τραγουδιών του εξωτερικού ακουγεται η φωνη να πετάγεται μπροστά απο τα ηχεια.
Πως γινεται.
Ένας λόγος που συμβαινει αυτο πρεπει να ειναι η γενναιόδωρη διαμόρφωση μαγνητοταινίας στην ηχογραφηςη. Περισσότερα στο προηγουμενο post:
https://euroelectron.blogspot.com/2018/11/making-vocal-jumping-out-of-loudspeaker.html
Πρεπει να ειναι πολυ λόγοι. Εκτός απο την σωστή χρήση των ισοφωνικων καμπύλων ακοής πρεπει να ειναι και το οτι οι τραγουδιστές δεν φωνάζουν.
Ετςι αυξάνει ο λόγος μέσου όρου σήματος προς αιχμές (peaks). Και ακουγεται δυνατότερα.
Making the vocal jumping out of loudspeaker
This is possibly made by analog recording to magnetic tape.
The following signal path was tried:
On recording:
Male singing voice - AKG MI 201-100 mic - Uher 4200 (1st bought on eBay) at 7.5ips, various rec modulation levels - BASF SM911 tape
On playback:
BASF SM911 - Uher 4200 (2nd bought on eBay), listening from its loudspeaker
While recoding various a Capella vocal takes of a demo song (Πως Θα Ηταν), the rec level knob was continuously increased after each take. The tape was driven more and more. Up to VU needle almost always after 0VU.
The hotter the tape was driven the more in front and out of the speaker the vocal sounds. It is not just louder, it sounds as nearer to listener's face.
A possible explanation is gentle rounding of peaks while average signal level is increased?
A nice thing about analog recording is that at playback the signal is integrated or high cut to get back to flat frequency response. So are heavily chopped peaks rounded off too?
Other reasons for a vocal jumping out (in front) at you may be the corect use of equal loudnes curves. And the fact that less loud singing makes a more loud vocal recording. The ratio of average signal to peaks is increased?
See also interviews of Mike Oldfield on how he created his guitar sound. By treble boost, clipping, then treble cut...?
See also analog Orban Optimod used before FM tadio transmision.
Upper track on tape is left channel
Source:
the master tape book - Alan Parsons, Bill Foster, Chris Hollebone
Forward by Phil Collins
The negative self bias of E88CC
Take all precautions.
The measurement readings below are very conservative. The actual self bias of grid is much more negative for at least too reasons:
1. An electrometer or pH potential meter was not used. Instead a digital multimeter was used with an input impedance of only 10MΩ to 1 GΩ.
2. The heater voltage used was 4.7V. The higher the cathode temperature the more negative grid becomes.
These measurements were done on Mullard E88CC electron tube in a Pleiades Electra 3 connection. Initially no voltage was supplied to plate. There was a plate to grid resitor of 10MΩ that makes operation of the amplifier possible at low anode potentials such as 12V-24V.
For more accurate initial measurements nothing at all should be connected to electron tube except heater voltage.
The negative terminal of the voltmeter was connected to chassis ground or cathodes.
The plus cable was connected to each grid in turn.
Firstly without connecting heaters, there is a potential at grid of about 200mV. This should be due to photo emmision as the electron tube was near the sun window.
Next 4.6V was supplied to heaters.
The grid gradually became -600mV. The other grid -550mV.
Anodes were respectively -400mV and -350mV.
A potential difference between anode and grid could not be measured (the 10MΩ resitor short circuits the high output impedance potential difference).
Next 24V were connected to anodes through the Sennheiser HD580 headphones. (See schematic, take all safety precautions (including ears of course) and suitable fuse in series with any battery).
Music was connected to grids through 22nF capacitors.
The sound was very nice. The 06 track of Fame soundtrack was being played.
Bias at grids was -50mV due to Pleiades bias (from the 10MΩ resistor, anode potential, and underheated cathodes).
At peaks bias was becoming more negative possibly due to the grid rectification effect [Armstrong].
At large peaks, bias became -100mV indicating reduction of gain or automatic gain control or compression.
Operating features of the Audion - E. H. Armstrong
Eyes should be protected too
This is not a medical advice.
For example when hammering, googles should be worn. There may be iron particles flying at top speed towards eyes.
Googles can also protect from toxic and eye irritating liquids hiting the eye. When wood paint removing for example. But then again paint removing substances are cancerogenic.
How to solder
This is not a medical advice.
It is stating the obvious.
There should be air ventilation and outdoors should be the best.
The air flow must take solder fumes away. The wind direction for example towards the back of the person who solders.
While soldering takes place we can arrange to exhale instead of inhale.
Cloth protection should be worn to protect cloths.
Gloves too to protect hands.
Googles too to protect eyes.
Hands should be cleaned thoroughly afterwards as there is lead in the solder.
Washing the body
Is is not a medical advice.
Could just using water or the least possible of soap be the best?
Soap, bathing liquids etc make skin dry. Then body produces oily substance to counteract.
Just using water and rubbing body leaves it clean and at a condition that helps keeping cleaningness during a day.
And spots may never come again. Stoping eating trans fat helps skin too as well as blood arteries from clogging.
Friday, November 9, 2018
Direct drive from anode to tape recording head part 8
At your risk. Take all safety precautions. A suitable fuse should always be used in series with a battery for thermal injury protection as well as fire hazard protection.
Summary: E88CC RC coupled and then a series resistor was tried today.
ECC83 direct to anode still sounds best. It seems worth carrying on with direct to anode experiments. With direct to anode there is sense of high class sound quality although so far there is distortion at high levels and s problems.
A brief description of today's E88CC head drive experiments:
Resistors were connected to anodes. Capacitor coupling. Series resistor to head. The usual stuff.
Values used:
Ra=4.7KΩ
Rs (series R to head)=17KΩ or 330Ω or 2.2KΩ.
Cc (coupling to head)=1μF, other channel 820nF
Rag=10MΩ
Vb=36V to 12V
Rb(DC tape bias resistor from 12V to head)=33KΩ for 400μA bias current
Almost all combinations sounded horrible.
With 17KΩ tape modulation is too low.
With 330Ω extremely high and with 2.2KΩ very high.
Almost unlistenable sound. ECC83 direct to anode sounds like paradise compared to this.
Other values of Rs need to be tried.
Treble was too low.
And treble does not increase when cathode temperature drops. This is possibly because the tube drives its load resistor and not an inductive load.
When an inductive load is driven and cathode temperature falls the increase in internal anode impedance creates a higher and higher high pass or low cut turnover frequency. This gives very sparkling acoustic guitar sounds.
ECC83 gave much more treble at normal cathode temperature.
Perhaps something else to be tried is ECC83 RC coupled with a higher load resistance and series resitor than E88CC and higher Vb.
There is also possibility of distortion at the grid circuit of the electron tube since the Sony CD player Walkman line out is directly connected to grids through coupling capacitors.
Something else needed to be tried is driving 2 tracks simultaneously from each triode ie 2 head coils in parallel. So that anode current can be 800μA which is a sensible current for ECC83. If this works it will immoderately make 2 track cassette (using almost full width of cassette tape) stereo from the Tascam Porta 03 head.
Something else that needs to be tried is forgetting cassettes and trying ECC83 anode to head on 1/4in tape running at 7.5ips.
Thinking about it, how can the Uher 4200 report have such great sound with just a small transistor operating at say 5V and low current? There is an inductive load at the collector instead of a load resitor. The designer must be a genius. An inductive load has also to be tried with ECC83 to save half Vb voltage and have bright and loud sound at the same time. Impedance coupling time? And a series resistor with of without series Cc to recording head? Or Cc with or without Rs?
BASF SM911, Per 368, Quantegy 632 tests on Uher 4200
Analog recording to tape is a different world.
Recording a single singing voice with signal so hot that VU meter needle is almost constantly between 0VU and end of scale,...,and it sounds fantastic. Just subjectively louder.
Below 0VU it still sounds fantastic. More silk and less aggression or loudness.
Signal path:
Recording:
Singing male voice at 1in - 4in from mic - AKG MI 201-100 - Uher 4200 report at 7.5ips - 1/4in virgin tape
Playback:
1/4in tape - Uher 4200 - resistor pad - Sennheiser HD580
Attenuation pad is 220Ω shunt to Uher 4200, 560Ω series with Sennheiser HD580. (At your risk, it is not known if this is safe enough).
2 Uher 4200 report recorders were used. Both having issues. They were bought on eBay. They sound fantastic but:
The 1st one bought ie Uher 4200 (1st) records and plays back on right channel only.
The second one bought ie Uher 4200 (2nd) plays back both tracks but records only right channel. Left channel recoding amplifier producing excessive distortion, (sounds like a high open loop gain system with no negative feedback).
Today SM911 and 632 were tested on mono right channel, track only.
Per 368 seems to sound similar or even better that SM911 but this is from memory. It was yesterday that a similar recoding which had been made a few weeks ago on Per 368 was played back. More tests are needed.
SM911 sounds more full and perhaps more bass heavy than 632. Possibly less hiss noise too. Both tapes were quiet anyway (speed 7.5ips).
632 sounds somewhat less loud but with perhaps more treble. It sound nice. But there is very high kind of static noise. Like playing a bad vinyl record.
This was more investigated and it was seen that adjacent layers of 632 were gently sticking to each other. Possibly signs of SSS syndrome? But 632 is not back coated. When unwinding by gravity and holding the spool verticaly by hand some static noise must had been heard too. So it seems to be electrostatic noise? There were no particles left on tape guides. Tape was stored and marked as ifie. Further tests were with SM911 only.
Recording on Uher 4200 1st sounds best in terms of HF reproduced on Uher 1st.
Recording on Uher 4200 2nd sounds best in terms of HF reproduced on Uher 2nd. Uher 2nd sounds best with more fantastic treble. So it seems there is azimuth discrepancy. Uher 2nd possibly has the correct azimuth adjustment. A test tape should reveal more.
Thursday, November 8, 2018
Direct drive from anode to tape heads (part 7)
At your risk. Take all safety precautions. A suitable fuse should always be used in series with a battery for thermal injury protection as well as fire hazard protection.
Signal path:
Recording:
Fame soundtrack CD - Sony CD Walkman at line out - Pleides V6, ECC83 - Tascam Porta 03 recording head - TDK SAX 60 cassette
Playback:
TDK SAX 60 - Sony TC-D5 Pro II - Sennheiser HD580
Referring to Pleiades V6 schematic.
Cc coupling capacitor to ECC83 grids is 2.7nF. Anode to grid bias resistor for each ECC83 section is 10MΩ. Supply voltage is 48V. Anode current is 400μA per each head channel.
This time ECC83, both sections were connected, one for each channel, so it is stereo. Best sound so far.
At playback VU needle goes up to 0VU. There is treble and a very nice sound. DC bias broadband fffffuuu hiss does not disturb. It is masked by music like listening to vinyl records.
So what is the problem?
There were some s problems.
Then Vb=36V giving a DC anode bias to heads of 200μA was tried. Much less sensitivity, more treble. Playback much less than 0VU. Hiss could be heard along music.
Vb=60V was tried too. Ia is 500μA. Unacceptable sound. Sounds like an expander.
Back to 48V and 400μA. Nice sound again. But track 01 Fame, fails. It sounds very distorted.
So next the Sennheiser HD580 headphones were connected to anodes before and after connecting the heads in order to monitor what quality of signal goes to the magnetic recording heads.
At the Fame track, with only HD580 at anodes, the sound is with very nice treble and deficient bass with some bass distortion. When connecting the heads in parallel, bass drops as expected since heads are inductors. Bass distortion dramatically increases.
Conclusion:
ECC83 with its high output impedance is great for premphasis, or constant current with respect to frequency head drive. But cannot direct drive such a low impedance load at low frequencies. The impedance of a head at very low frequencies goes too low.
So what seems best is to do what had been done all those decades.
Introduce a series resistor between amp and head for constant current drive.
(So it is again the same problem as with L only Pleiades microphone filters. Bass may distort due to source or load. An R,L filter is needed ie R in series with L. Bass will drop at R while the source of music signal, be it a mic or an anode, will see a high impedance). On microphones an (R series with L) high pass filter can be connected in parallel with voice coil and signal taken from voice coil. This creates a gentle slope less than 6dB per octave low cut. On tape heads a series resistor is usually feeding the head. Output of the filter is the inductor or head itself, so the low cut filtering is 6dB per octave, series R reduces stress to inductor and signal source and increases low cut frequency. Is this frequency 20KHz? Then due to the head gap losses etc, at reproduction high cut (integration) must stop somewhere and we have the well known playback deemphasis time constant.
What could be done in an effort to keep Vb low while solving the problem?
A clean low voltage ECC82, (ECC83?), E88CC could still be tried with other Vb or anode to grid bias resistors but direct anode coupling may not be the way. Impedance coupling may be the way.
If a clean higher supply voltage ECC83, ECC82?, E88CC circuit may be needed... Impedance again coupling may be the way. A high inductance inductor at anode producing flat voltage frequency response with large voltage excursions. Then capacitor coupling and series resistor. As it is done on the wise Uher 4000, 4200, 4400 report series using a transistor. It typical uses a 10-13 KΩ resistor with or without a shunt 1200pF capacitor (for extra treble boost) depending on model, see Uher 4000 report schematics.
Since the Uher uses small voltages, low currents, 1mA?, it may be possible to use electron tubes with Pleiades bias at small anode potentials, E88CC? but the anode would have to be coupled to head through a series resistor. Uher report typically uses 10-12 KΩ from transistor collector to head.
What else was gained?
These experiments provided an opportunity to see how brilliant the sound of many electron tubes is when Sennheiser HD580 headphones are connected directly to anodes (Pleiadss Electra 3). Pleiades bias immediately reduces distortion. Anode potentials from 12V to 24V seem ideal but attention to hearing safety is required. Sound Presure Levels must be always kept low for protection of the hearing mechanism.
DC tape bias may not that bad after all. Distortion took place because the signal going to heads was distorted in the first place. But perhaps easier magnetic saturation of tape may had made things worse? Not likely as DC bias seems to had been near the centre of the limear part of the H-B tape curve. DC tape bias hiss sounds louder, nice and thick, ie not treble heavy. It is nice for experimentation. If AC bias is needed an oscillator can be added later on.
Next day addition. After trying E88CC, RC coupled and then reries resistor, ECC83 direct to anode still sounds best and it seems worth carting on with direct to anode tape head drive sxperiments. Different values of series R to E88CC need also to be tried. See part 8.
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Wednesday, November 7, 2018
Operating electron tubes at low anode potential
At your risk.
This can be done by reducing the negative self bias of the grid (by the electron cloud of thermally emmited electrons).
This can be done for example by a 10MΩ resistor from anode to grid.
The electron tube then operates with great sound quality at a very low plate potential. Well said Hliana.
Λειτουργώντας (Λυχνίες) σωλήνες ηλεκτρονίων με χαμηλή τάση
Με δικη σας ευθύνη.
Αυτο γινεται με ελατωςη της υπάρχουσας αρνητικής τάσης (απο νέφος θερμο εκπεμπόμενων ηλεκτρονίων) στο πλέγμα των σωλήνων ηλεκτρονίων.
Αυτο μπορει να γίνει πχ με μια αντίσταση 10ΜΩ απο άνοδο στο πλέγμα. Ετςι λειτουργούν με πολυ χαμηλή τάση στην άνοδο με θαυμάσιο τροπο, ήχο. Μπραβο στην Ηλιανα.
E88CC with Pleiades bias directly diving headphones
At your risk. Protect your ears. A suitable fuse should always be used in series with a battery for fire hazard protection.
Signal path:
Sony CD Walkman line out - Pleiades Electra 3, E88CC Mullard - Sennheiser HD580
It sounds spectacular.
Cathodes connected to ground. 10MΩ resistors from anode to grid to reduce grid negative space potential. 2.7nF coupling capacitors to grid so as not by upset DC potential of grid. Vheater=5V (so PCC88 could be used with 6.3V?).
Headphones directly connected to anodes. Vb connected to headphones ground (an insulated chassis headphone socket is used).
At Vb=12V (actually 10.4V as battery had discharged) there is some distortion as anode current is 300μA.
At Vb=24V E88CC nails it. At Vb=36V it may already be too dangerous for human hearing. Even 24V may be too much, it is not known.
The sound is big and amazing. Great bass, mid and treble. This is what electron tubes are for.
Would E88CC operate well at 12V with a lower anode to grid resitor? How would the sound compare to EF183 triode connected? How would ECC86 sound? How would vari μ ECC189 sound?
ECC86 almost nails it with just Vb=12V (10.4V), Big sound. Vh=4.7V. Rag=10MΩ. At such conditions Ia=1mA, Vg is pulled up to approx -300mV. Further cathode under heating sounds nice too, gentle peak distortion seems decreasing as sensitivity is decreased too, so rails are less often approached when music is playing. At Vb=24V, Ia=4mA, (anode dissipation 24Vx4mA=96mW so theoretically 48mW max output if there is impedance matching) much louder, possibly hearing unsafe.
ECC86 was tried with lower Rag resistors ie approx 1MΩ. At Vb=5V, it is amazing how much distortion is reduced by changing from 10MΩ to 1MΩ. At Vb=12V, Ia becomes 2-2.5 mA. Great sound but there is some lack of bass. Possibly due to reduced input impedance so the Cc capacitors have to be increased.
ECC82, 12AU7 could operate at Vb=12V, Vh=12V or less and Rag=10MΩ. Decreasing Rag increased Ia but bass again reduced, Cc must be increased? At Vb=24V, Rag=10MΩ the sound is very nice.
E88CC could operate too at Vb=10.5V with Rag of the order of 1MΩ. Similar perhaps problem with bass.
Gut feeling is that the best sound so far on Pleiades Electra driving headphones is E88CC at Vb=24V, Rag=10MΩ. Very big sound. Protect your hearing by listening at low SPLs.
Next the ECC83 will be plugged in as the objective of these recent Pleiades experiments is direct driving a tape recording head with the usual needed high output impedance for constant current drive of the head coil, ie increasing treble with frequency. See nearby posts.
ECC82 directly driving headphones
At your risk. Take all safety precautions. Also always use a suitable fuse in series with a battery for safety and fire hazard protection.
The Pleiades Electra 3 schematic was used which is very similar to the Pleiades V6 schematic. The Pleiades V6 is intended as a low noise mic booster amplifier. The Pleiades Electra is intended as power amplifier. They are virtually identical circuits. Both have a pull up bias resistor from anode to grid to make operation possible at low plate voltage. See Pleiades Bias.
Today an old, (before 2000) unused Pleiades amplifier aluminum box was modified to include two 10MΩ anode to grid resistors. The intention is to direct drive magnetic tape recording heads with an ECC83.
Other modifications... Cathodes are connected to ground. Grids are connected to 2.7nF for DC isolation. The above mentioned 10MΩ from anode to grid, making the grid less negative, ie pull it up out of cutoff.
Why is the open grid to cutoff? Because the cathode is emitting electrons to form an electron cloud between cathode and grid which repels electrons. The cathode is positive with respect to grid since protons are left behind inside the cathode. Therefore the grid is negative with respect to cathode.
The headphones are the load themselves, with DC passing through them.
Signal path:
The song: Is it OK if I call you mine? - Gore, from CD - Sony CD Wlkman line out - Pleiades V6 - Sennheiser HD580
Before connecting anything to the anodes, current was measured between anode and Vb.
At Vb=10.5V and ECC83, Ia was approx. 20μA. The headphones were connected and a very faint sound but of good but distorted sound quality (a lot of distortion could be heard).
Then Vb was changed to 24V, marked improvement, 36V even better, 48V even better. At 48V anode
current is of the order of 350μA. Great quality sound with amazing treble. This may be used to direct drive tape recording heads. Magnetic heads need to be driven by a high output impedance and want voltage headroom for HF. (Constant current drive with respect to frequency since a head is an inductor whose impedance increases with frequency). It is amazing how the ECC83 with an output impedance of the order of 50kΩ could drive 300Ω headphones with power loss of course but a clear sound.
Then the ECC82 was plugged in. At Vb=10.5V, Ia is already 400μA. So the amplifier operates even at 12V.
At 24V and 36V the sound improves together with sensitivity and max power. At 48V where current is 3mA it may already be too much.
A triode connected EF183 ekectron tube gives 1.5mA at Vb=12V. And 2.5mA with Rag of 1.5MΩ.
Would E88CC operate well with Vb=12V or Vb=24V? Ia with Rag=10MΩ and Vb=12V is 300μA, at Vheater=5V.
How would ECC82, ECC83, E88CC perform with Rag=1.5MΩ?
Tuesday, November 6, 2018
The history of the song Unchained Melody
https://m.youtube.com/watch?v=LrquswYcwV0#fauxfullscreen
Murray Burbridge YouTube channel
It is interesting to compared different production styles.
See also:
https://en.m.wikipedia.org/wiki/Unchained_Melody
Doppler Effect Again
Je t' aime, moi non plus - Gainsbourg, Birkin
https://m.youtube.com/watch?v=k3Fa4lOQfbA#fauxfullscreen
(See also Hammond organ and Leslie speaker.)
A bass line can escort many melodies
Or many melodies can escort the same bass line.
There as many examples one of them is bass going up in steps of 4th intervals, (harmonic chain).
The example used on this post is step bass. Bass going down step by step the scale.
In fact the following musical examples all use the same scale, C major. So bass goes Do, Si, La, Sol, ...
Air on G string - Bach, arrangement Lousier
https://m.youtube.com/watch?v=14AhD3xdoMk
Piano Man - Billy Joel
https://m.youtube.com/watch?v=gxEPV4kolz0#fauxfullscreen
(In both above examples a higher part E caries on creating an F major 7th chord when bass goes down to F. Fa La Do Mi. This is exactly what Bach is doing on the original Air in G string in D major. The beautiful chord created is correspondingly G major 7th, G B D F#).
Unchained Melody - North, Zaret, Righteous Brothers, producer Phil Spector
https://m.youtube.com/watch?v=qiiyq2xrSI0
(Similar effect with respect to time, the bass going down 2 steps).
Again when bass becomes F, melody sings E (my da( E )rling...) to create the fabulous F major 7th chord).
Don't Let it Show - The Alan Parsons Project
https://m.youtube.com/watch?v=gzb6bC_ZVJo
A Whiter Shade of Pale - Procol Harum
https://m.youtube.com/watch?v=Mb3iPP-tHdA
Sowing the Seeds of Love - Tears for Fears
https://m.youtube.com/watch?v=VAtGOESO7W8
(Do, Si, La, Sol, Fa bass is used in the chorus. Verse bass is going down step by step the G minor scale.)
Towards the end of the song 2 melodies are used together with the same bass line.
Listen also to Viva La Vida - Coldplay, producer Brian Eno
See also:
Bach Bass Rules, instructions of Bach to his students:
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
The Doppler (frequency shift) effect in music
A great example:
Us and Them - Pink Floyd
https://m.youtube.com/watch?v=s_Yayz5o-l0
The speaker connected to the organ is possibly a Leslie. With its rotating reflector and counter rotating tweeter horn it creates frequency modulation caressing listener's basilar membrane.
A very nice effect can be created by rotating a small speaker inside its small open back cabinet hanging by the cable itself. At your risk. Take all safety precautions. See also the Pleiades (rotating) speaker.
See also:
https://en.m.wikipedia.org/wiki/Doppler_effect
Conceptual Physics - Hewitt
Driving a tape recorder head directly from electron tube anode, Part 6
At your risk. Take all safety precautions. Including a suitable fuse in series with any battery for fire hazard protection in case of a short circuit.
ECC83 is nailing it.
Signal path:
Recording:
[Is it OK if I call you mine? - Paul McCrane, CD] - Sony CD Walkman - Pleiades V6 ECC83, Rag=10MΩ, Vb=48V, Cc=27nF, Vh=12V, Rh=10Ω - 1 track side A head coil of Tascam Porta 03, normal tape speed - TDK SAX 60 cassette
Reproduction:
TDK SAX - Sony TC-D5 Pro II - Sennheiser HD580
The heaters where powered by 12V in series with 10Ω.
An anode to grid resistor of 10MA was connected to ECC83 for reducing the self negative (from cathode electron emmision) bias and create an anode current of 360μA at only 48V at the anode.
The recording head was connected in place of an output transformer, ie to Vb and the other terminal of the head coil to anode.
So DC tape bias is 360μA.
How does it sound like?
Just one side of ECC83 was connected to left channel of recording head. So reproduction at headphones is only on the left channel.
Reproduction was surprisingly good. With no distortion. This time there was treble and no bass heaviness. This is due to the high anode internal resistance of ECC83. Modulation was up to 0VU. The hiss was thick broadband since DC bias is used.
An ECC82 was also connected. Vb=12V so that Ia is 500μA. It was bass heavy or lacking treble as in previous experiments. There was some distortion, possibly coming from the Pleiades V6 operated at less anode power dissipation, that is having less max power output.
A great example of numbered bass notation
Adagio in G minor - Albinoni, Giazotto
https://m.youtube.com/watch?v=uJVlbLK7VbA#fauxfullscreen
Giazotto had found the numbered bass (see the numbers above each bass on the contra basso line), [Bach, Niedt] of Albinoni, hundreds of years later and co created the masterpiece.
Reference:
Bach Bass Rules:
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
Step Bass examples
Adagio in G minor - Albinoni, Giazotto
https://m.youtube.com/watch?v=VAtGOESO7W8#fauxfullscreen
Bass Descending G minor scale at intro, then going up G minor.
(See also how 7ths etc are prepared from previous chord and the 3rd added to the new bass [Bach-Niedt]).
Piano Man - Billy Joel
https://m.youtube.com/watch?v=gxEPV4kolz0#fauxfullscreen
Bass descending C major scale
Sowing the Seeds of Love - Tears for Fears
https://m.youtube.com/watch?v=VAtGOESO7W8#fauxfullscreen
At verse descending G minor scale
At chorus descending C major scale
Reference:
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
Pedal Bass examples
Us And Them - Pink Floyd
Bass is D throughout the intro and verse.
The other parts change creating magnificent harmony.
The figures bass code [Bach-Noedt] is:
The key is D major ie all notes are natural or white keyboard expect F which is F sharp and C which is C sharp).
D9
D69 (means having the 9th and 6th above D ie, E and B)
D(3b)7
D46
D(7)9
This above means.
D bass and the sequence of sustained notes for example D E D A E D E
D bass and D E D B F E F (remember F is F#)
D bass and D F A F C A F A (here F is natural but remember C is C#)[2]
D bass and D G D B G D E
D bass and D E D A E D E
Pedal bass can be generalized to another higher part.
For example a vocal singing the same note for example D while other parts are changing. Sowing the Seeds of Love - Tears for Fears is a magnificent example. On verse voice sings mostly D. Bass is descending the G minor scale step by step. G bass and D is the usual 135 chord, harmonic triad. But then F bass and D creates F6. E and D creates Eb major 7th...[Bach-Niedt].
https://m.youtube.com/watch?v=VAtGOESO7W8#fauxfullscreen
Other example a guitar playing just a high note A for a long time while bass changes. For example the beginning of With or Without you - U2
https://m.youtube.com/watch?v=6DeDzsCGbsQ#fauxfullscreen
Reference:
Bach Bass Rules (source is Spita's biography of Bach)
Edited by Norman Schmidt: https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
[2] The composer Rick Wright explains how he got this chord from his love of Jazz, on the DVD, The Making of Dark Side of the Moon - Pink Floyd
Monday, November 5, 2018
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