The sound chip of the Amstrad CPC464

Is this: AY-3-8912


http://www.ym2149.com/ay8910.pdf


Later addition: there is at least one mistake in this post. The AY-3-8912 has D to A converter as seen on block diagram of datasheet. But it seems it is much different concept to what we mean nowadays. Manual states that output of the sound chip is from sub audible to supersonic (eg 150KHz). So does this mean that the D to A is fed by a clock of say 2MHz?

Also production of tones is produced by division of square waves  beginning from a high clock frequency.


So it is really the same idea as the amazing Solina String Ensemble, Farfisa, EKO organs etc which all have division of square pulses to create the raw material for musical notes.


So in fact it is analog but with software control like the amazing Italian EKO organs.


Or perhaps even like TB-303 or Rolland Juno-6 or Siel DK70. Of Cource these as the EKO organs etc use analog filters or ain't her analog envelop signal processing etc.


Later addition. The TB-303 has VCO oscilltor.


But they all sound great.


No nasty digital to analog (bliakh) converters.


Even the ZX Spectrum BEEP command in BASIC sounds great which just a square pulse or whatever. Electrons moving back and forth.





More on Amstrad sound:


Music and Sound on your Amstrad - Ian Sinclair - Melbourne House

Connecting the ZX Spectrum computer to the Amstrad monochrome GT85 monitor

At your risk. Take all safety precautions.


The petticular ZX spectrum used has the hardware hack of taking composite out just before the RF transistor inside the screen small box.


Composite out was connected to pins Sync and Lum (luminance).
Thanks to Bryce:
http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/connecting-another-computer-to-a-gt65-cpc-monochrome-monitor/


By looking the male DIN coming from the monitor these are bottom right and central pin respectively. Upper right is ground ie ground pin connected to ZX spectrum ground.


It worked. But for some reason picture is shifted to the left a bit. So the leftmost parts of what Spectrum produces cannot be seen.

If it does not operate maybe the on switch had not been switched on

This is exactly what had happened after some frustration that an Amstrad CPC464 had developed a malfunction. In fact it has an on switch at the right hand side.

The song Something Stupid - Sinatra has pedal bass on the female voice

This had been realized today while listening the modern song version (Nicole Kidman, Robbie Williams) on an FM Beolit Bang and Olufsen radio.


The female vocal part keeps singing the same nite while the male part is moving in pitch. This must be happen quite a few times. Amazing effect creating very interesting harmony.

Don't t give away your electron tube portable mono reel to reel recorder

See previous posts


If it does not sound much better than commercial recordings this has nothing to do with the speed of tape, quality of your mic etc. See today's posts.

A Uher 4200 report hack for natural singing voice reproduction

See previous post.

A gentle slope low cut without having to spend thousands of dollars to EQ

Many times the more expensive and better the equipment (including microphones) are, the more bass heavy and unnatural the reproduced perception to listener's brain is.


And of course the furthest the sound quality is from a commercial record.
For example:
Out Here in my Own - Gore, Gore, Cara from the Fame soundtrack


This is because of [Lowe, Morgan]:
Fletcher Munson equal loudness curves
Voice effort curves
Proximity effect
Bass reverberation of rooms (recording or reproducing)


A nice perhaps unmatched in quality trick is to use nature itself or the principle of superposition.


The trick of Lou Burroughs (Electro-Voice) as described in his book Microphones is used.


2 omnidirectional mics are connected out of phase.
Or electrically added out of phase etc.


This is described in more detail on previous posts.


By singing to one mic and adjusting the distance of the other, ambience is canceled and the distance between the 2 mics changes the cutoff frequency making for example bass rumble, voice bass or mid heaviness disappear while voice remains crystal clear.


Perhaps this so useful trick can be expanded and the slope of high pass filtering changed by controlling the level of the far off microphone.


In fact level change already takes place as the closer the furthest mic is brought the higher the direct sound level it captures.





The above hack was confirmed by chance while recording a demo on an Uher report 4200 (at 7.5ips tape speed).


One Beyer M55 mic was connected to channel input 1 and another Beyer M55 to channel input 2.


Channel 1 was recorded to tape track 1.


Channel 2 had been recorded to tape track 2 at the same time.


One mic was used close to singing voice.


The other mic was used close to a Yamaha PSS-14 little keyboard.


Now when listening to playback after many months, singing voice sounds bass heavy if the voice track is heard on its own.


But when both channels are sent to the monitoring speaker voice becomes great and clear. Some for the little keyboard.


It had been found latter on that by good chance one of the microphones had been wired out of phase.


When monitoring trough an external linoleum Pleiades Auratone 5C type speaker the difference in voice quality is sparkling.

Difference between minor scale (Aeolian) and Dorian scale

For example A minor.
A B C D E F G A


A Dorian
A B C D E #F G A


We deduce that the 6th with respect to (tonic or root) bass is a minor 6th in the case of A minor ie
A F
whereas it is a major 6th ie
A #F in the case of A Dorian


And of course this can be generalized for all Dorian scales as opposed to all minor scales.


So if the bass goes down by 4 steps the allowed chord is a major 3rd one which is exactly what makes  the Dorian scale sound interesting and uplifting.
Example
On A Dorian
We can have D and D #F A ie D major 3rd chord if we harmonize with the basis 1 3 5 harmonic triad rule.
Or for example bass code
D6 is D bass D #F B ie D major 3rd major 6th chord


Other examples of Dorian scale:


Breathe - Pink Floyd (in E Dorian)
We were playing E minor to A (major) for an hour or so [Waters]


To Get Lucky - Daft Punk (in B Dorian}
1 st chord is naturally B minor
But 4th and final chord is E major 3rd and not minor 3rd
This is because B Dorian is:
B #C D E #F #G A B


Other example:
Veridis Quo - Daft Punk (in D minor)
Progression from D minor 3rd to G major 3rd, (not G minor 3rd).
D Dorian is:
D E F G A B C D (all natural)


Easy Peasy. But only a few people on the planet take the time to realize it.


Reference:


The Making of the Dark Side of the Moon - DVD (quote by Roger Waters on composing or rather jamming while creating Breathe - Pink Floyd

La Havouge

Προσεχώς στους κινηματογράφους.


Coming soon to a cinema near you.

Winding 300 turns on 3B8002 Magmet? tape wound ring core?

A possible use is a 1:3 or so mic to base transformer.  How would signal to noise ratio improve?Possible connection to a Uher 4200 or Sony TC-D5 etc.


Magnetic toroidal core dimensions are approx. outer diameter 1inch, inner diameter 0.5inch.


Inductance of a 300 turns (of wire for the secondary winding) turned out about 5.9H.

Hello to Ukraine

Hello to Germany

Gardners Transformers

The 1972 GT.5 Audio Frequency Transformers
Gardners Ttansformers Limited, Christchurch
has just been skim read.


Here are elements that were found important:


Print quality.


How large the new factory is seen in pictures.


That the company had been modestly started by 2 brothers.


That the very very high bandwidth Super Fidelity wide band microphone and line matching transformers were toroidally wound.
Typically plus or minus 0.2dB to 80KHz for MU.7582.
Typical examples:
MU.7582
MU.7584
MU.7590


Ultra high permeability Nickel-Iron core had been used.


The standard MU.7513
MU.7514 etc
were published typically +/-0.5dB 50Hz to 10Khz which may also be a good thing, see previous post.


Many ranges of bandwidth were available in between.

Are audio, recording studio, military signal transformers etc the best investment on the planet?

The Gardners lower bandwidth series MU7513 mic or line to grid transformer sold on eBay.co.uk for about £80 on 18 August 2019
eBay item no: 123871427096


Bidding was missed.


But the rare GT.5 Gardners Audio Frequency Transformers catalogues had been bought on eBay.
And the kind seller included price list documentation and a 31st October 1972 vintage letter from the factory to the person interested.


Price for MU7513 on Sptember 1972 is:
£2.97


Can't imagine what would today's price be if so many university textbooks did not speak low on them suggesting opamp energy consuming alternatives with capacitor feedback to simulate an inductor etc or active balanced stages etc.


Thanks to academics price is kept low.


The MU7513 (+ or -) 0.5dB bandwidth is published 50Hz to 10KHz.


So why?


Perhaps one reason is exactly this fact.


They reduce bass or treble heaviness due to Fletcher Munson, Voice effort effects etc so that singing voice sounds with flat frequency response not from mic to loudspeaker but much more importantly from singer's vocal chords to listener's brain. [Lowe, Morgan]


Reference:


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

The Jostykit HF365 stereo-coder

Please do not expect to learn anything as I do not know.


It has to be written for myself.


This kit from the amazing Dutch Jostykit company is usually used for its FM coding capability.


But it seems the real gold is the quality of the FM oscillator.


It is just one transistor. It is p n p and mabe p n p versions of a complimentary transistor may have 1/4 of the bandwidth if checked on datasheet. This might be a deliberate choice by the designers so that even if harmonics are created they are diminished?


There is a nice varicap (variable capacitance diode) implementing the frequency modulation.


Very neat circuit.


The schematic can be found on this nice webpage:
https://www.circuitsonline.net/forum/view/106114/last


All it should need is preemphasis for flat frequency response by a series resistor in parallel with a small capacitor connected at audio input. Values should be chosen according to continent standards, 50μs, or 75μs.

An way to stereo transmit on FM

At your risk.


If correctly remembered Stereo FM transmition involves sending to the frequency modulated oscillator or exciter the following signal in frequency domain:


1 normal mono ie Mid signal of max bandwidth say 20Hz to 15KHz.


2 the L-R signal ie Side signal as sidebands with centre or carier frequency 38KHz.


In time domain this involved adding to the Mid signal an amplitude modulated carrier of 38KHz by the Side signal.


So what would be easier than assembling a couple of musicians in non reflective surroundings. Placing a Mid Side (stereo) microphone or mic technique and creating an encoder that utilizes directly M and S rather than creating as in the particular mic case it already exists.


But who needs stereo anyway?

A dream soundtrack

Even th greatest of all composers, J. S. Bach needed some notes from others for inspiration [Anna Magdalena Bach]. He might use a few notes from his friend price (a musical offering in D minor).


Below are some notes listened in today's dream. If you can and would like you may develop it.


Time signature is 3/4.


Key is A minor ie all notes white or natural.


Bass code / melody possibly played with strings


A /      E D C
A/       B A #G
E/        B D D
E/         rest
D/        F E D
F/        C B A
E45/    B -  -
E/         -  -  -





Reference:


The chronicle of Anna Magdalena Bach


See also Bach Bass Rules PDF

Connecting ZX spectrum or Yamaha CX5M computer to 80's pocket television

Unreadable. Even with a magnifying glass.


Possible cause, small resolution of such LCD portable TVs. Or different number of horizontal, vertical pixels between transmiter and receiver. Is there a beat pattern created?

How does music publishing operate?

The most difficult to understand concept.


Possibly the most important.


Even when there is a cover version of a song royalties will find their way to the music publisher and eventually part of it to the songwriter.


Another example on next post in Hellenic language.

Τι σημαινει publishing στη μουςικη βιομηχανία;

Το publishing ειναι η πιο αφηρημένη έννοια.


Ξεκινησε αιώνες πριν με την έκδοση παρτιτούρας.


Εχεις το copyright, μπορεις αντιγραφεις όσες φορες θελεις και να πουλάς.


Στη σημερινή εποχή εχει και άλλες μορφές.


Παραδείγματα:


Μπαίνει μουςικη σε ταινια κινηματογραφική, δικαιώματα πληρώνονται στον εκδότη.


Για να δούμε στοιχειωδώς τη ροη χρήματος ας εξετάσουμε ενα άλλο παραδειγμα.
Μπαίνει διαφήμιση στην τηλεόραση η στο YouTube. Ολα ονειρικά και αθώα, καλλίγραμμες ξανθιές με μαύρα φρύδια, ξάπλα σε νοικιασμένο η δανεισμένο κότερο, μουςικη (σαγηνευτική η μη)...
Τρέχει ο καταναλωτής να αγοράσει το υποσχόμενο παραδείσου προϊόν.
Τα χρήματα που δίνει στο περίπτερο τα παίρνει ο περιπτεράς. Δίνει λίγα στο κράτος, λίγα στον διανομέα.
Ο διανομέας λίγα στο κράτος λίγα στην εταιρία του προϊόντος.
Η εταιρία λια στο κράτος λίγα στην διαφημιστική.
Η διαφημιστική λίγα στο κράτος λίγα στο τηλεοπτικό κανάλι.
Το τηλεοπτικό κανάλι λίγα στο κράτος λίγα στην ΑΕΠΙ.
Η ΑΕΠΙ λίγα στο κράτος λίγα στον εκδότη της μουςικης.
Η εταιρία (συνηθως πολυεθνική) εκδότης της μουςικης λίγα στο κράτος λίγα στον καλλιτέχνη.
Ο καλλιτέχνης λίγα στο κράτος λίγα στην τσέπη του για να ξαναγοράσει τσίχλες η τσιγάρα απο το περίπτερο και να κλείσει ο κύκλος του παραδείσου.


Αλλα παραδείγματα, το AirPlay στο ραδιόφωνο.


Κτλ.

Χαρυ Κλυν Δοξάστε με

https://m.youtube.com/watch?v=plBFnE9Szcs

If Andrew Lloyd Webber does not have a mobile phone then why should I?

On a recent interview in City and Town magazine.

Αν ο Αντριου Λοιντ Βεμπερ δεν εχει κινητό γιατι θα πρεπει να εχω εγώ;

Απο πρόσφατη συνέντευξη του Andrew Lloyd Weber στο (περιοδικό) City and Town magazine.

Το τζαναμπετικο γατουλι

Υπαρχουν ονειρικές χαβουζιτσες;

The Great Gig in the Sky - Pink Floyd sounds hilarious with playback Varispeed in the low direction

Observation by Vicky.


Would this suggest that a voice can be made to sound like a fairytale nymph with Varispeed in the high direction?

Με Varispeed προς την αργή κατεύθυνση η φωνη ακουγεται σαν να σου πατάνε τον καλο

Παρατήρηση της Βίκης οταν ακούστηκε το αριστουργηματικό


The Great Gig in the Sky - Pink Floyd με εςκεμενα σαφώς μειωμένη ταχύτητα αναπαραγωγής αναλογικής μαγνητικής ταινιας.


Μηπως αυτο σημαίνει οτι με Varispeed προς την αντίθετη γρήγορη κατεύθυνση μπορει η κάλου πατημένη φωνη να ακουστεί σαν νεράιδα ονειρική;

Η ελειψη Varispeed στην Γρεκικη δισκογραφία

Ευτυχώς τώρα που βγαίνουμε απο την κριση τα πράγματα αλλάζουν ραγδαία.


Μη ξεχνάμε ομως και την μοντέρνα ιστορία.


Νταχ τιριτι, χανουμ, γιαβρουμ και σκανταλιάρικο τσιφτετέλι.
Όλοι σέρνονται έντεχνα σαν Χέλι.


Και η φωνη με ακριβό φθηνιάρικο πυκνωτικο μικροφωνο επίπεδης απόκρισης συχνότητας να ακουγεται σαν λασπουλα.


Και αντί η ταχύτητα αναπαραγωγής να αυξάνει να μειώνεται σταδιακά.


Η φωνη να ακουγεται σαν να σου πατάνε τον καλο.


Και η φωνη να γιινεεταααιιι όλο και πιιοοοο μμπαααασσσσσααα σαν μια απρόσμενη κολλητική χλαπατσα.


Και η φωνη να γινεται όλο και πιο χοντρούλα σαν με πλούσιο φυνικαιλαιο μπουγατσουλα.


Και ολα να λιώνουν με πιο μπαςο μονο που το φοινικελαιο σαν σαπούνι δεν λιώνει.


Και η φωνη να γινεται οολλλοοοοο και πιιοοοοοοο χοοοοοντρρηηηηηηη.


Και με άφησες εμένα τα ξημερώματα
Και λειωνω λιώνω εγώ μόνος στα πατώματα.


Να ρίχνονται ολα στο πάτωμα.


Να εισπράτει η ΑΕΠΙ.


Να φεύγει τσεκ για την λιγο πολυεθνική.


Να παίρνει ο συνθετης ποσοστό.


Να λιώνει ο συνδαιτημονας στο πιοτό.


Να φεύγει τσεκ για τη βιομηχανία ποτού.


Τι Γρεκια  , τι Τουμπουκτου.



Ντέρτια σκελετικά και η φωνη να ακουγεται σαν απύθμενη χαβούζα, σαν βοοουροοοοσσσς.


Ευτυχώς ολα τώρα έχουν πια αλλάξει.


Και η χώρα του φωτό λάμπει κατω απο αληθινές ακτίνες Ηλιου δεν αφήνουν κακιά σκια στην αλήθεια.

Hello to Hellas

FM radio transmitters

At your responsibility.
At your risk.
Safety.


About radio part 41 quality audio FM transmitsr
https://m.youtube.com/watch?index=3&list=UUzEeZM7nzH02_BIM5zkU2tg&feature=plcp&v=8Vkeco8zS5g#fauxfullscreen


Also:
https://www.circuitsonline.net/forum/view/106140/2


And the simple and nice Jostykit HF65:
It had been great playing with my cousin when teenagers with 2 of them, voice radio communicating with electromagnetic waves in real time during afternoons.
It possibly needs audio preemphasis to counteract radio recover deemphasis.
A way may be (a resistor in parallel with capacitor) in series with audio signal for HF boost
Or similar arangment with inductor, resistor in parallel with audio signal etc

Andrew Lloyd Weber's autobiography is being published

New use for analog handheld TVs (televisions) for precision audio monitoring

They can be bought for almost peanuts as analog TV broadcasting is abandoned at the moment.


They should simulate very well how music will sound on portable devices but are should also be useful for finding faults in an audio production.


So all needed is a battery power handheld PocketbTV from the 80s having an AV (audio video) input so that it can be used as monitor or even better audio monitor. A portable device with audio line in very handy.


The one tried today sounds very good. The tiny speaker reproduces well transients.


TVs always sound nice as they have just one drive unit.


They can put to shame audio systems costing thousands of dollars.


The particular tiny TV connected to the Sony CD Walkman reproduces really well the Sound Check 2 CD - Alan Parsons.


Only for example the train and the fighter plane did not sound very good.


Plenty of sources did sound good to amazing.


For example:


The pipe organ, soprano opera, acoustic guitars, piano (sparkling high notes), string orchestra, noises including electronic ones.


The tiny TV sends to tea systems costing megabucks.


Alan Parsons voice sounds very realistic too.


The portamento sinewave tone is good too.

Broken TVs with an X line across

They are handy as they tell, "better not watch this".

Transformers must also look good not only sound good

Hammond transformers,


for example vintage grey painted broadcast sealed types with solder tags look amazing.

Was The Great Gig in the Sky - Pink Floyd, Torry recorded with Varispeed?

This is guesswork.


But it sounds like it.


All Alan Parsons had to do was reducing backing track tape speed (say one semitone?) just before Clare Torry offered to the world her amazing performance.


Today a type II Denon HD6/60 cassette recorded from Linn Sondek LP in the 90s was played back on a Sanyo TRC 2500.


It sounded great. Then out of curiosity it was decided to use the Sanyo speed knob adjustment to reduce speed a bit. Voice sounded more like an ordinary human being.


Then speed knob was back to 0. Out of this world.


Interesting.

How would opera singing recording sound with say 1 semitone Varispeed?

Would singers sound young and fresh like some pop music masterpieces?


For example to France - Mike Oldfield


See also next post on The Great Gig in the Sky - Pink Floyd, Clare Torry

Reducing speed variation in cassette recorders, players

Wow and flutter may be due to a worn belt.


But more abrupt variations for example while holding a portable cassette player may be due to imperfect battery contacts.


Such was the case while playing around with Sanyo TRC 2500. Even the power LED would dim while holding it.


Yet battery holder contacts looked not bad with no corrosion.


But from experience with very sensitive mic booster preamps such as the Pleiades V6 electron tube battery powered amp, sound that resemble earthquake can be produced by just gently touching around battery holder.


So it was decided to look into it. Battery holder metal contacts were gently streched in the opposite direction of battery pressing. While looking through a magnifying glass it was seen that the second coil of the spring has to touch the first coil when it is compressed by the battery. On one of the battery holders the second coil from the spring was dislodged from the support of the 1st turn. It was out back in place.


Then contacts were cleaned with methylated spirit and cotton buds. Then 1000 fineness wet and dry abrasive paper was gently used. Then methylated spirit again for top cleaningness.


Now Sanyo TRC 2500 plays almost like new.

We have the power over fear - Mari, Εχουμε την εξουσία πανω στον φόβο - Μαρι

As Philosopher Epictetous says:


We have the command (or the power over) 4 things:
Perception
Desire
Choice
Refusal



(We do not harm ourselves or others
Δεν κανουμε κακό σε εμάς η αλλους)


So as Mari understood it we can for example choose not to be afraid.


Fear does not exist anyway
Lampros


Συμφωνα με τον Φιλόσοφο Επίκτητο στη εξουσία μας υπάρχουν 4 πράγματα:
Η αντιληψη
Η επιθυμία
Η επιλογή
Η άρνηση


Αρα μπορουμε για παραδειγμα να επιλέξουμε να μην φοβηθούμε - Μαρι


Ετςι και αλλιώς φόβος δεν υπαρχει
Λάμπρος

Sean Davies with electron tube stereo disk cutting lathe system

Analog Planet channel
https://m.youtube.com/watch?v=wAj22g8MWkw

How is Varispeed done for fresh sounding vocals etc

Below examples assume that the backing track has already been recorded on the same medium. What follows mentions how to record the vocal or vocals.


If using magnetic tape, reel to reel, cassette etc...
Reducing tape speed while recording and adjusting speed back to normal on playback.


It an be done digitally on software Samplitude for example. Reducing sample rate by adjusting playback settings. Recording at that setting and then bring back to normal.

Gunshot bass patch for the Yamaha PSS-480

So much can be done in this synth having just FM operators and few parameters to adjust.


This patch came by editing the 58 Synth Bass voice:


Transpose -12 is used.


parameter, value


0,47
1,61
2,00
3,06
4,01
5,01
6,07
7,87
8,78


Sounds pretty nasty and horrible.

Cleaning battery leak deposits from a keyboard

At your risk. Take all safety precautions. Gloves etc. Common sense.
Worst case scenario may be Ni-Cd batteries as Cd has radioactive isotopes. Make sure you read everything before deciding what to not or not to do.


Today, yesterday a heavily (alkaline) battery leaked Yamaha PSS-480 FM keyboard synth had been cleaned. Plastic surfaces had been almost painted with rust. It was eventually cleaned with methylated spirit and cotton buds.

How is voice made to sound fresh, πως γινεται ηχογραφήσεις φωνητικών του εξωτερικού να έχουν φρέσκια νεανική χροιά;

On the previous post:
https://euroelectron.blogspot.com/2019/08/varispeed-example.html


Στο προηγουμενο post:
https://euroelectron.blogspot.com/2019/08/varispeed-example.html

Varispeed example?

Voice possibly without Varispeed :
My life is going on - Cecilia Krull - Antena 1
https://m.youtube.com/watch?v=5Fggbxuo3W0


Possible Varispeed example:
It could have been recorded with backing track playback speed such that key becomes a semitone lower, vocal sung and recorded, then (recording tape?) speeded up (or sampling rate increased?) a semitone higher so that key is correct and voice sounding fresher.
My life is going on - Cecilia Krull (video official)
https://m.youtube.com/watch?v=F1oHBcTdKL4


See also recording engineer Michael Tretow's interviews on recording ABBA with varispeed

The Atlantic records story

Khaz606
https://m.youtube.com/watch?v=-4K6OSIsDaQ#fauxfullscreen

Ahmet Ertegun

rockhistory.co.uk
https://m.youtube.com/watch?v=nDyNDnEzmzg


https://en.m.wikipedia.org/wiki/Ahmet_Ertegun

Is the major scale called Ionian mode on the honor of Pythagoras?

https://en.m.wikipedia.org/wiki/Ionian_mode


https://en.m.wikipedia.org/wiki/Pythagoras


This may make sense if Pythagoras was the first to study the frequency of various overtones of a vibrating string.


https://en.m.wikipedia.org/wiki/Overtone


Such overtones correspond more or less to notes:


C
C octave
G oct
C double oct
E d oct
G d oct
Bb d oct
B d oct
C triple octave


So most of the notes of the major scale are already contained in the complex vibration of a stretched string.


See also Leonard Bernstein lecture at Harvard university - YouTube


See also Musical Acoustics - Hall

My life is going on - Krull and Smalltown Boy - Bronski Beat

have the same bass code
Key is B minor. Ie all notes natural or white except C, F which are sharp.


(Later addition: post is wrong. 4th bass note on My life is going on is G and not D. Also the 3rd bass code is E#3 ie E major and not E ie E minor, scale is B Dorian ie has the G sharp too so E is E major or major 3rd)


B B B B
A A A A
E E E E
D D D D
and back to beginning


Would they create  a nice mashup?


Tempo is much difference.

Hello to Hellas

Συμβολίζοντας την μουςικη αρμονία (συγχορδίες) με διανυσματα

Στο προηγουμε post:


https://euroelectron.blogspot.com/2019/08/on-representing-musical-harmony-with.html

On representing musical harmony with multidimensional vectors

If it is said that little Ionas for example can be good at mathematics and not good at music may not be true.


How can one be good at mathematics and not good at music?


For they are one and the same.





And now trying to find a way to write chords as vectors (ordered pairs etc).


Usually in music melody somewhat goes up.


So usually bass goes down as Bach recommends that hands move in a mirror like fashion [Bach].


For example:
Old and Wise - Alan Parsons Project
(Writen in A minor scale ie
La Si Do Re Mi Fa Sol La or
A   B  C   D  E    F   G    A


So naturally bass starts at A


Almost quite commonly bass goes down step by step:


A  then G then F then E then F then E then D then E then A
(Introduction, orchestra strings etc)


What makes it so beautiful is the bass code ie:

A ie A C E
G6 ie G B E
F7 ie F C C E
E7 ie E G B D
F7 ie F A C E
E7 ie E G B D
D7 ie D D A C
E7 ie E D B D
A#3 ie A #C E


Now since Ionas is quite good at negative numbers too...


Can't we call like we do at electronic engineering, ground level potential at 0.
Like sea level height 0


So tonic bass ie A is just 0.


So bass becomes:


0 then -1 then -2 then -3 etc


Then complete Harmony becomes


(0,3) ie A minor 3rd


(-1,6) ie G major 3rd major 6th


(-2,7) ie F major 3rd major 7th


(-3,7) ie E minor 3rd minor 7th


(-2,7) ie F major 3rd major 7th


(-3,7) ie E minor 3rd minor 7th


(-4.7) ie D minor 3rd minor 7th


(-3,7) ie E minor 3rd minor 7th


(0,#3) ie A major 3rd


Easy peasy.


Problem is that it is still hard to visualize that disonant intervals are prepared to the listener's brain as required by Bach. For example in above example the high note E is being played in a pedal constant sustained way by the right hand creating all those fantastically sounding intervals with respect to bass. Ie A E, G E, F E, E D, F E, E 6, D E etc
Whereas when we play it we can see it happening. Or when we look at the score we can see it happening.


But we can hear or feel it anyway.


Even those who do not "know" music can feel it anyway. Those millions of satisfied listeners.



Reference:


Bach Bass Rules
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf

The Pleiades V6 mic booster amplifier schematic is so simple...

it can be engraved on the enclosure.


For example a Hammond orange die cast aluminium enclosure.

Examining the frequency response curve of the Shure Beta 58A

http://www.jie-yun.com.tw/_equipment/3mic/data/BETA58A_specsheet.pdf


At 2ft from the microphone there seems to be a very gentle low cut frequemcy response below about 3KHz. This should aid for flat frequency response from producer's brain to listener's brain. [Lowe, Morgan]


Reference:


Sound Picture recording and reproducing characteristics - D. P. Lowe, K. F. Morgan - Journal of the society of motion picture engineers

Hello to Hellas and Germany

Μπορεις να με σκοτώσεις αλλα δεν μπορεις να με βλάψεις - Επικτητος

Απο το Εγχειριδιο - Επικτητος - Τόμος Δ - Εκδωσεις Κακτος


http://classics.mit.edu/Epictetus/epicench.html

You can kill me but you cannot hurt me - Epictetous

From


Enchiridion - Epictetous - PDF


http://classics.mit.edu/Epictetus/epicench.html

Datasheet of Fairchild BC549

https://www.sparkfun.com/datasheets/Components/BC546.pdf

Fairchild small signal transistors

http://bitsavers.org/components/fairchild/_dataBooks/1977_Fairchild_Small_Signal_Pro-Electron_Cross_Reference.pdf

Mullard tubes and special products

http://mirror.thelifeofkenneth.com/lib/electronics_archive/MullardTubesSpecialProducts1972-73_text.pdf

Other uses of the electrometer electron tube

At your risk.


They can be used to make a very sensitive microphone booster front end amplifier.
Or for example an active electric bass DI box.
See previous posts, Pleiades V6 with CV2269 electrometer electron tube.


Other use is:
The Victoreen ionizing radiation meter:
https://www.orau.org/ptp/Library/cdv/victor717-1.pdf

From flash Ram to Aristotelian logic in a few important steps Απο τα φλασακια μνήμης στον Αριστοτελης με λίγα σημαντικά βήματα

Flash memory
Wikipedia:
https://euroelectron.blogspot.com/2019/08/resonance-takes-place-when-excitation.html


Then hitting the link logic gates
https://en.m.wikipedia.org/wiki/Logic_gate
Then looking at truth tables


Or
https://en.m.wikipedia.org/wiki/Boolean_algebra


Or Aristotelian logic
https://en.m.wikipedia.org/wiki/Term_logic


See also:
Aristotelian logic
Truth tables of
And  or
Or   or
Not


For example:


AND


I eat oranges and apples is only true when I eat both


Truth table is


T and T is T
T and F is F
F and T is F
F and F is F


I eat oranges or apples is only false when I do not eat either


Truth table is


T or T is T
T or F is T
F or T is T
F or F is F


Logical proposition is a proposition that can either be true T or Glase F


For example


I eat oranges


Or I eat apples


Much of mathematics is based in Aristolelian logic or sets or theory of sets



Electronic logic gates are 3 terminal devices where if say 5 volts or 0 volts are applied to either of input pins 5V or 0V are at the output depending on what type of gate.


For example an AND gate gives 5V or logic 1 only when 5V or logic 1 are connected to both onputs.


Logic gates with feedback are the basis of memory. Then we have registers, microprocessors, computers, the Internet.


It is amazing how much hard work has taken place by so many people.

H αρχη απροσδιοριστίας του Χαιζενμπεργκ στη μουςικη, Haisenberg's uncertainty principle in music

See previous post:
https://euroelectron.blogspot.com/2019/08/resonance-takes-place-when-excitation.html

Resonance takes place when an excitation frequency approaches the self frequency of a system

Examples:


A kid is on a swing. The self frequency depends on the length of the swing chain.
We can make the amplitude of oscillation large only if we push at the correct time intervals. Ie at the same frequency as the self frequency.


We change the length of an antenna to match its self frequency to that of the radio station we are interested in listening or tuning in.


A soprano breaking a glass when she sings at the same frequency as the natural frequency of the glass.


Soldiers marching all at the same frequency and this frequency happens to be the resonant frequency of the bridge.


Singing near a guitar the note D and then hearing it vibrating.


Singing A4 for example near a piano where sustain pedal is pressed. We then can hear the piano repeating.


In fact we hear the piano repeat at the tone quality of our voice like reverb. This happens because our voice has many overtones. These overtones excite the right strings or overtones of the piano strings.
Ie the piano does Fourier analysis and synthesis in real time.


When we clap our hands the piano repeats the clap sound. Clapping our hands creates a board band frequency spectrum and all strings vibrate sympathetically.
Other way to look at it is that the wave by our clapping hands creates a push air presure pulse so short in time that the strings do not have the time to move back while this is happening. So all strings move. Even the high frequency ones.


This means that the shorter a pulse the greater its frequency spectrum or bandwidth.


This is the Heisenberg's (quantum mechanics) uncertainty principle in acoustics.


The less a tone lasts the less we are sure what note it is.


The shorter an event the grater bandwidth it creates. For example turning on or off a light switch would create a click sound to an AM radio no matter to which frequency it is tuned. The short breaking of circuit is such a short pulse that the electromagnetic waves emitted have content even at radio frequencies.


See also:


Waves - Berkeley Physics Course - F. S. Crawford Jr.


Musical Acoustics - Hall


The Feynman lectures on Physics - Feynman, Leighton, Sands

Making a radio with a toroidal coil

At your risk. Take safety precautions. Any voltage or current can be dangerous.


A simple,radio can be made by about 60? tourne of thin insulated wire wound to a toilet paper cardboard form.


Then connecting it in parallel to 2 aluminium foils separated by larger size A4 paper.


Radio AM stations can be turned by moving one of the foils relative to the other as this crates a variable capacitor.


Capacitor in parallel with inductor creates an electrical reasonance ciruit.


One of the plates is connected to ground.


The other plate is connected to a long antenna wire.
It is also connected to the grid of an electron tube.


It had been tried long time ago on the input of a Pleiades electron tube MM cartridge RIAA preamplifier. Sound was very good. Electron tube non linearity or even the grid rectification effect demodulates RF to audio. [Armstrong]. This  is like creating a side chain voltage out of the transmition program. This side chain signal is at audio frequencies so we can listen to the music.


Would it also work with the coil be wound in ring (toroidal) shape? Taking advantage of the hum
bucking properties of such shape.




Reference:


Operating features of the Audion - E. H. Armstrong

LC-Electronic Bega 20

At your risk. Take safety precautions. Any voltage or current can be dangerous.


This seems to be a Geiger Muller counter. Operates with a 9V battery.


It must have been read somewhere that they synthesize counting.
This must be done by the 4551 IC converging voltage into a proportional pulse frequency.
https://www.bucek.name/pdf/xr4151.pdf


I does not count at the moment, although it used to work. Digital circuit and display seem to operate.


Hoping it is an electrolytic capacitors age problem.


On a small circuit board are 2 10μF/16V and on a larger digital board is one 22μF/25V. ICs are 4011, 4012BE, 4040BE, 4060. All start with HCF and end with BE. Made by ST.
Transistors are C558B, C548C and a bent one which can't be read. All transistors are Philips having the silver painting and the PH logo.


The smaller board has a C558B transistor and a 8 pin IC RC4151N.


There are also electronics inside the electron tube housing. This must be a step up oscillator circuit and high impedance active device circuit.

Το καινούριο κόλπο της Κανελινας και της υπομονετικής χελώνας για να μην ακούγονται οι τραγουδιστές φωνές σαν βουλωμένες χαβούζες

Με δικη σας ευθύνη.


Στο προηγουμενο post με αναφορα στο βιβλιο του Lou Burroughs (Electro-Voice).
https://euroelectron.blogspot.com/2019/08/the-best-parametric-eq-on-earth-with.html


Απλα συνδέουμε εν σειρα δυο παντοκατευθυντικα μικρόφωνα επίτηδες εκτός φάσης. Και τραγουδάμε μονο σε ενα απο τα δυο. Ο θόρυβος οπως και τα λασπώδη μπάσα απο αντικειμενικά και υποκειμενικά φαινόμενα φτάνουν εξίσου και στα 2 μικρόφωνα και αλληλοεξουδετερώνονται αφου τα μικρόφωνα ειναι συνδεμένα εκτός φάσης. Ηλεκτρομαγνητικά κύματα συγκρουόμενα. Η παλλόμενα ηλεκτρόνια συγκρουόμενα.

The best parametric EQ on earth with a next to nothing cost

At your risk.


It is revisiting the great idea explained by Lou Burroughs (Electro-Voice) in his book. [Burroughs]


Signal path:


Male singing voice in untreated room - 2 Beyer M119 omni microphones connected deliberately out of phase - (Pleiades (130Ω,40mH) filter if needed) - Sony TC-D5 as mic preamp - Sennheiser HD580 - listening singer's ear brain perception


"Technology is doing a lot with little"
Michalis


How does it sound like?


When mics are equidistant in front of singer, almost nothing is heard as expected. This verifies that the particular setup is corrects connected, that mics are matched etc.


By holding both mics by hands...


When distance of mics is several feet all sort of ambient noise can be heard, similarly to listening through an ordinary setup with just one mic. Birds can be heard, but also room ambience, bass heaviness, the very low frequency sound of neighbours' air conditioning, machinery etc.


As mics are approached a parametric low cut frequency effect sets in. Machinery, low rumble etc disappear.


Mics further approaching and mid ambience disappears.


Mics further approaching and only HF content of birds etc can be heard.


The same happens when one sings only to one of the mics while moving around the other.


Voice bass heaviness disappears, as distant mic move closer.


The good thing is that nature provides with an infinite choice of cutoff frequencies. Just by changing the distance of the far mic.


So the ideal of flat frequency response from producer's brain to listener's brain can be approached.


Advantage is the disappearing of much of the ambient sound as well as room bass heaviness etc.


The Pleiades filter was connected too for comparison or additional effect.


Except for producing a very bright sound it is not needed.


The Pleiades filter on its own sounds similar to the above setup while producing a bit more HF.


But the 2 mics out of phase setup, sounds great with perhaps a better or more emphasized midrange.


Mics were just connected in series, ie pin 2 of one mic to pin 3 of the other and remaining pins to mic input. Actually this has the advantage of creating a 200Ω + 200Ω = 400Ω resultant magic mic.


Ambience visits more or less equally both mics and since they are connected out of phase it cancels.


Am amazing trick.


Reference


Microphones - Lou Burroughs

A way to write, close to writing on the sand

At your risk.


The apple green Tarket linoleum 2m x 1m carpet had not been cut for a tetrahedron pyramid speaker. Frequency response problems.


So it had been used one day for a little nap.


Recently it had being used for writing down the Pleiadss V6 CV2269 schematic.


More recently for writing down measurements of various audio transformers.


It is also used as a nice rest of those Hammond enclosures, electron tube bases, sealed audio transformers with pin sockets etc.


It looks very nice. A permement orange marker is used.


If a mistake is being made, it is either left or erased very easily with a cotton ear bud swab moistened with methylated spirit.

Frequency response of Gardners transformers

Found by google search with keywords;
Gardners MU7514 transformer


https://www.americanradiohistory.com/hd2/IDX-Site-Early-Radio/Archive-Wireless-World-IDX/70s/Wireless-World-1976-07-OCR-Page-0009.pdf

How are the constant impedance constant K Equalizers designed

It is on books such as:


Elements of Sound Recording - Frayne, Wolfe


Cinema engineering


Audio Cyclopedia - Tremaine


Papers of H. R. Kimball on the Journal of the Society of Motion Picture Enginners


Textbooks, papers that the engineers of EMI, Altec, etc  must have had access to.

Altec

9200A console
http://steampoweredradio.com/pdf/altec/altec%20model%209200a%20console.pdf


Equalizers
http://www.vintageradio.com/history/Altec1966.pdf

Langenvin microphone preamplifiers, Altec 9475a

langevin AM16 schematic
searching on Google


https://www.gearslutz.com/board/so-much-gear-so-little-time/29052-altec-9475a-mic-preamps-class.html

Another one transistor amplifier (with a BC547)

At your risk. Take safety precautions. Any voltage or current can be dangerous. A fuse must be used in series with any battery for fire hazard protection. Protect your hearing.


http://www.theorycircuit.com/simple-single-transistor-audio-amplifier-circuit/


Includes an electret mic connecting circuit.


Great it is going well.


Soon so many people on our planet would start to be listening to music.


Datasheet of BC547:
https://www.sparkfun.com/datasheets/Components/BC546.pdf

Beyer M119 to Pleiades (130Ω,40mH) to Gardeners MU 7514

Signal path:


male singing voice - Beyer M119 at 2-8 in - Pleiades (130Ω,40mH) - Gardners MU 7514 1:2 transformer - Sony TC-D5 Pro - Sennheiser HD580 - listener's (singer's ) brain


Without the Pleiades gentle slope low cut filter sound is bass, mid heavy. If the particular (R,L) resistance inductance values filter is connected at the 800Ω side sound is very treble heavy. So it is left connected at the 200Ω side.


Without the Gardners transormer which steps up 600Ω to 2400Ω therefore 200Ω to 800Ω sound is with less volume, some bass heaviness and some treble heaviness.


When the Gardners is inserted in the signal path it acts as a magnifying glass. Sony is much better modulated. For example the rec level potentiometer can be at 7/10 instead of 10/10 for same VU meter modulation. So less hiss.


Amazing quality transformer.


The slight reduction of very low bass or very high treble frequencies make for a flatter frequency response from producer's brain to listener's brain. For an explanation the reader is referred to either [Lowe, Morgan] or [Hilliard].


References:


Sound picture recording and reproducing characteristics - D. P. Lowe, K. F. Morgan - Journal of the society of motion picture engineers


A brief history of early motion picture sound recording and reproducing practices - John K. Hilliard - JAES vol 33 no 4 apr 1985 page 276

The best way to combine 2 signals

At your risk.


Of course the simplest way may be to just connect 2 microphones is series or in parallel. There is impedance increase or decrease which can be a good thing. It has been tried suceesfully on various Pleiades experiments.


If no signal coupling between the 2 devices is needed and preserving the impedance with minimum loss then the best way on our planet at least must be the hybrid transformer. It can be seen on the great Cinema Engineering Hollywood books. This is how adding (mixing is a wrong term) consoles were made.


2 hybrid transformers can even create balanced in, balanced in balanced out.


Here is the Wikipedia article:
https://en.m.wikipedia.org/wiki/Hybrid_coil


Of course hybrids can make the best mic spliters too.

Perhaps the only things that can't be bought in our times are ...

copies of love,


fresh fruits,


What else?


Health cannot be bought. But if one reads, follows the basics, no illness will knock the door. It is amazing how many mass produced food products write on the ingredient list with those tiny wee wee letters palm oil or fat. Anyway this is not a medical advice. At your risk.

Hello to Argentina

Playing with microphone transformers, variable microphone setup ratios passive amplifier

At your risk. Take all safety precautions.


Many modern microphone preamplifiers may have a input impedance of the order of 2KΩ to 20KΩ.


Most microphones have an output impedance of typically 200Ω.


It can be fun to make a small turn ratio step up transformer acting as a passive mic booster amplifier.


It can be wound on a ring core. Suitable cores may be made by Arnold, Magmet, Magnetec etc.


Or a transformer could be bought. For example a Hammond 600Ω to 2400Ω, 2 primary windings, 2 secondary winding.


4 pole switches can be used for primary or secondary.


In this way all four terminals per primary or secondary windings can be administered to other terminals of the switch so that either series or parallel connection is implemented.


So then by just using 2 switches all 4 combinations are possible such as:


150Ω to 600Ω


600Ω to 600Ω


150Ω to 2400Ω


600Ω to 2400Ω


And it is even more important as at first glance since direct windings (number of turns of wire) have a different inductance. So the interaction of such inductance and microphone output impedance may create the right low cut response for getting rid of the so annoying bass heaviness. So they may aid to the goal of flat frequency response from producer's brain to listener's brain.


The transormer can be housed inside a Neutrik module box. So everything is small, elegant, professional looking, with Neutrik XLR input and output connectors.

Why ring core signal transformers may not even need a magnetic shield

At your risk. Take all safety precautions.


On so many Pleiades microphone, input transformer, one or more active device amplifier experiments usually a microphone is connected to an input transformer. The input transformer may be capcitively coupled to an electron tube control grid. An output transformer then feeds an ordinary microphone amplifier.


Such tremendous detail amplifying arrangement with so much total gain might be expected to have a huge magnetic or electromagnetic pickup interference susceptibility.


Yet output is in most cases clean of such man made artifacts even if the front end input transformer is magnetically unsealded.


Why is this so?


One reason is the use of batteries (in series with a fuse for fire hazard safety). Batteries do not radiate hum as power transformers, chokes, rectifier arrangements do.


Other reason is that low cut filter coils or mic transormer coils are wound on ring or toroidal cores. The toroidal shape is possibly the most magnetically efficient shape (in the universe?). And if a core of high permeability is used almost none of the internally generated field leaks out and none of the external man made fields can get in.


But even if no core is used, ie winding toroidally on air, still most of the interference is out.
The reason seems to be that the ring core winding shape is hum bucking at any point of the circle circumference.


That is for any one turn of wire there is one on opposite side of the ring core circle circumference (at 180 degrees) of opposite winding direction. Since they are in series what they pick up or what they would radiate cancel.

A nice game for teaching music (acoustic memory etc)

Teacher plays C


Student repeates C


T plays C F


S repeates C F


T plays C F G


S plays C F G


T plays C F G A


S plays C F G A


T plays C F G A G


S plays C F G A G


T Plays C F G A G E


S plays beginning of Chariots of Fire


Can this be generalized to bass, chord progressions etc.


Can this be implemented as an electronic game?


Exercise may be done with eyes open or shut.


Notes played may even be random, for example a melody just created.

Do electron tubes behave as bass, mid compressors (automatic gain control) wity grid leak resistor dectating release time?

At your risk. Take all safety precautions.


For some strange reason it sounds better reducing bass, mid heaviness due to proximity effect and well known psychoacoustic phenomena after the electron tube rather than before it.


Considerng the following signal paths:


male singing voice - mic - Pleiades (R,L) low cut filter - mic input transformer - electron tube preamp - output transformer - main mic preamplifier - headphone amplifier - monitoring headphones - listener's brain


It sounds nice.


But the following may sound even better:


male singing voice - mic - (Pleiades (R,L) filter) - mic input transformer - electron tube starved at low anode voltage, very low anode current - output transformer - main mic preamp - headphone amplifier - monitoring headphones - listener's brain


Bass cut in the 2nd example is mainly produced by the high electron tube internal anode output impedance interacting with output transformer primary inductance. [MIT staff]


Why does bass cut after the electron tube sounds better than before it?


In order to understand the compressing effect of electron tubes reference is to [Armstrong].


Even a world class mic or especially a world class mic can sound amazingly horrible by bass heaviness on a flat frequency response setup. We know the reason why is that the objective is not flat frequency response from mic to loudspeaker but from producer's brain to listener's brain [Lowe, Morgan].


But how do electron tubes do the trick of transforming a horrible sound feeding them to a very listenable sound that could even be a standard hit song sound quality, listened, enjoyed by so many listeners on the radio?


How do they transform crapiness to gold?


Some relevant experiments are described on recent posts on the one electron tube Pleiades V6 CV2269 mic booster amplifier.


Is a possible explanation that the low uncut signal has a larger envelope thereby creating greater rectification effect at grid. This DC changes bias to more negative and therefore decreases gain. Release time of the compressing effect is dictated by the grid bias or grid leak resistor. Low cut is implemented by the output transformer. So effectively we have a compressor with boosted bass or mid frequency (compressor side chain) content due to proximity effect etc at side chain. Flat frequency response to listener's brain is effected by said interaction of electron tube with output transformer.


Or is it just the gentle slope bass or treble reduction from the output's transformer interaction with electron tube?


Or both?


Or other reasons?


References:


Magnetic Circuits and Transformers - MIT staff


Operating features of the Audion - E. H. Armstrong


Sound picture recording a reproducing characteristics - D. P. Lowe, K. F. Morgan - Journal of the Society of motion picture engineers

The Pleiades bias had been discovered accidentally

At your risk. Take safety precautions. Any voltage or current can be dangerous. A fuse in series with a battery must be used for fire hazard protection.



It is a pull up bias suitable for low level electron tube amplifiers operating with very few volts at the anode.


On around 2000 meeting with Sean Davies in London, Sean Davies mentioned using electrometer electron tubes for condenser microphones.


Some time after back to Athens a CV2269 electrometer tube was investigated for its suitability for a mic booster amplifier.


Initially on breadboard just 2 batteries were used and a tiny microammeter from a broken JVC Nivico 9425W radio. Nothing else, no mic etc.


A grid resistor had been connected to either of the filament leads.


But filament leads are connected to the 1.2V battery.


By connecting grid resistor to the +1.2V terminal anode current dramatically increased.


At some point it was observed to great surprise that leaving out the anode battery and short circuiting the corresponding amplifier terminals made the microammeter needle move, ie electron tube amplifier was operating and there was anode current. Connecting grid return resistor to the positive terminal made an important difference.


So this can be an amplifier with 1.2V battery connected to filament and same battery used as anode supply.


Later on it was realized after Hliana insisted that grid should not be biased negative that in fact by pull up bias (this time with a resistor from grid to either anode or Vb) grid still remains negative but less so making operation possible with almost any electron tube and very low anode potential. Even for 12AU7 (ECC82), 9-12 volts at anode is fine to more than enough.


Smoothness of sound, low electron velocity, low temperature, posiblilty of deliberate cathode under heating at such low anode potential creates a low noise front end amplifier with minimum secondary electron emission effects.


Perhaps now it is time to go back to CV2269 and use the Pleiades V6 schematic to make a hardwired mic booster amplifier of such low power consumption that it can be portable and operate for perhaps days with just an AA battery. Current drain at 1.3V is less than 13mA (including of course cathode filament).


Low anode current (of the order of 15μA) has the added advantage of amplifier reducing bass heaviness due to Fletcher Munson, voice effort curves, and the proximity effect. Thereby assisting in flat frequency response from producer's brain to listener's brain.


Use of military signal transformers as suggested by Lefteris much earlier can further assist in this direction. For example materials such as Mumetal? where permeability decreases with frequency thereby creating a gentle slope high pass filter. Or using in shunt with microphone a Pleiadws (R,L) gentle slope low cut or high pass filter. (By gentle slope less than 6dB per octave is meant.)


World class microphones such as Fostex M80RP, Sennheiser MD441 etc can be connected to such amplifier with the advantage of having a ready produced vocal sound quality without the need of other analog or digital signal processing.


Another advantage is that it sounds loud getting advantage of the psychoacoustic properties of electron tubes with just one electron tube due to the low supply rail. So without having to resort to driving many electron tube stages at mastering or earlier stages of production for a rich vocal sound. The low gain of the Pleiades V6 CV2269 (V7?) mic booster insures that following mic preamplifier will not be overloaded. So even operational amplifiers may be used which otherwise can be unsuitable for live music production. [Hamm]


The Pleiades V7 combines the elegance and excellence of the Neumann U47 schematic [BBC] and the RCA BA-2C mic booster amplifier with the advantage of battery portability and nearly pocket size compactness. [Euroelectron]


A possible disadvantage is not as world class low noise as its bigger brother the Pleiades V6 EF183 or Nuvistor 7586 operating at 3.6V including heaters and anode circuit.


See also:


The Pleiades bias - euroelectron


Operating features of the Audion - E. H. Armstrong


(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 motion picture engineers


Tubes vs transistors (vs op amps), Is there an audible difference? - Russel O. Hamm - JAES


http://downloads.bbc.co.uk/rd/pubs/reports/1954-23.pdf


(This includes the schematic of Pleiades V6) http://euroelectron.blogspot.com/2018/03/pleiades-v6-offspring-of-rca-ba-2c-and.html

Hello to Hellas and Germany

A nice book explaining magnetic core materials

High frequency magnetic components -  Dr. Marian Kazimierczuk


https://books.google.gr/books?id=p3KHPUhaOaUC&pg=PA65&lpg=PA65&dq=νικελ+core+magnetic+permeability+vs+frequency&source=bl&ots=nhk6eL3rBB&sig=ACfU3U1o0cLfOwtdBWYCONvIyjU_aKz_Ew&hl=el&sa=X&ved=2ahUKEwiM7-vd8ITkAhUQNOwKHZg9AcwQ6AEwDXoECAoQAQ#v=onepage&q=νικελ%20core%20magnetic%20permeability%20vs%20frequency&f=false


For example the 80% Ni (Nickel) core material is called Permalloy or Mumetal


Didn't know this.


Wikipedia has very nice articles showing the difference between the two:


https://en.m.wikipedia.org/wiki/Permalloy


https://en.m.wikipedia.org/wiki/Mu-metal


See also silicon steel
https://en.m.wikipedia.org/wiki/Electrical_steel

Input transformers from Hammond

For example:
http://hammondmfg.com/pdf/140NEX.pdf


This one has low primary inductance. So with a 200Ω it may compensate for bass heaviness due to proximity and other psychoacoustic effects creating a natural balance.


Here is the studio series:
http://hammondmfg.com/140EX.htm

Nice series of Hammind boxes

http://hammondmfg.com/dwg_SBVer.htm

Elegant or simple schematics can be written on a linoleum carpet, wall frame etc

It is under consideration whether a Pleiades V6 CV2269 prototype should be made inside an orange Hamond die cast aluminum box.


Everything can be inside including military quality mic input, output transformers.


A 4 pole 2 position switch could toggle between 150Ω or 600Ω inout transformer primary winding connection.


Even at such a low component count circuit the octagon box is almost full of components. Their relative position is being considered for minimum wiring length. This is done while sitting on a linoleum carpet.


The Pleiadss V6 schematic with the direct heater electrometer electron tube can be drawn on the carpet with an orange marker.

Another great example of the major 3rd major 7th chord

Love is in the Air - Young


Very characteristic, the beautifully sounding 2nd chord,
F major 3rd major 7th
ie Fa La Do Mi or
F A C E

See also:


Bach Bass Rules:
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf


Harmony - Piston

Hello to Serbia and France

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Hello to Portugal and South Korea

Tuning with beats

Beats Demo: Tuning Forks - Physics Demos - YouTube
https://m.youtube.com/watch?v=yia8spG8OmA#fauxfullscreen


Beats - Bozeman Science - YouTube
https://m.youtube.com/watch?v=4M72kQulGKk

Best sound so far

At your risk. Take safety precautions. Any voltage or current can be dangerous. A suitable fuse must be in series with any battery for fire hazard protection.


It has that Yesterday - Beatles vocal quality.


Anode to grid bias is by a 20MΩ resistor. Not known yet what the optimum is. About 2MΩ decreased gain dramatically.



Signal path:


male singing voice - Fostex M80RP at 7in - Pleiades (130Ω,40mH) - Pleiades V6 schematic implemented with the CV2269 electrometer electron tube with Peerless 4722 input transformer and Pleiades 10:1 output transformer powered by a 1.4V battery - Sony TC-D5 Pro mic in - Sennheiser HD580


Electron tube CV2260 booster front end amplifier operating conditions are:
Approx 1.4V at electron tube anode
Approx 10-15 μA anode current


Low noise. Not the lowest noise. It seems if it becomes lower noise by increasing for example anode current sound quality would become bass heavy by change in anode internal resistance.


Various top quality mics had been tried such as:


Beyer M119
Revox D19
Fostex M55RP
Revox M3500 (Beyer Dynamic M201?)
Shure SM63


They all sounded so different as if coming from a different planet.


Suddenly breadboard contacts were self cleaned and preamp became much more low noise.


It is amazing what can be done with just an electron tube.
Still it is not the lowest noise preamp but it discriminates very much between open low impedance circuit and 0Ω linked XLR.


Electron tube smooth and great natural sound.


The 2DV4 Nuvistor electron tube, see previous post, at 1.4V gave lower noise but mid peaky sound. Anode current is much less at such low anode potential.

New use for electronic tuners

When it shows correct you know you are doing something wrong.


It should be great fun to measure the frequency of the very high note on Gonna Fly Now - Bill Conti at 0:52.
https://m.youtube.com/watch?v=ioE_O7Lm0I4#fauxfullscreen 

It works also the other way round. When the electronic tuner shows wrong you know you may be doing something right.



It measures frequency but it cannot measure (perceive) pitch as we humans do.


But it has the urge to fly. Don't throw it yet to the recycle bin. It is useful.

How would the BC109 transistor sound on a Pleiades V6 single ended input, output transformer one active device schematic?

BC109 microphone booster?


The BC109 is the low noise transistor used in the EMI TG12345 multiway mixer or the Uher report 4200 portable broadcasting reel to reel magnetic recorder.


What would be an optimum operating voltage. Small, large? Operating current? Small, μA order like electron tube battery circuits?

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1.5V Nuvistor electron tube 2DV4 microphone booster preamplifier Pleiades V6 experiments continued

At your risk. Take safety precautions. Any voltage or current can be dangerous. A fuse must be used in series with any battery for fire hazard protection.


It had been siting on the Pleiades V6 experimental breadboard jig for some months.


Today it was connected to the Fostex M80RP flat coil ribbon figure of eight microphone.


Schematic is the Pleiades V6:
https://www.flickr.com/photos/photoulia/35858046756


Signal path:


Male singing voice at 7in - Fostex M80RP - (optional Pleiades (130Ω,40mH) gentle slope high pass filter - Pleiades V6 with 4722 Peerless Altec input transformer, 2DV4, Rag=2.4MΩ, Vb=1.5V, Pleiades 10:1 output transformer - Sony TCD5 Pro mic in - Sennheiser HD580


Energy is from a AA alkaline battery.


This front end preamplifier takes about half a minute to start operating as heater is deliberately underheated at 1.5V.


The 500μA meter at anode circuit needle barely moves indicating about 1-2μA? But it does move as witnessed with a magnifying glass and amplifier operates like a magnifying device too.


Hiss or thermal noise can be heard as amplifier warms up. If a short circuit is connected between ground and input capacitor hiss almost disappears. If a short circuited XLR (0Ω) is connected to low impedance input (transformer primary through perhaps loose breadboard connection) hiss is reduced but not as much. Both conditions indicate a reasonable low noise performance.


When mic is directly connected to Sony it sounds so bass heavy that sound is unusable.


If a Pleiades (130Ω,40mH) gentle slope low cut filter is connected between mic and Sony preamp the sound is nice with just a bit of bass heaviness left and high bandwidth which may make the sound overall uninteresting.


If the mic is connected to the Pleiades V6 2DV4, no Pleiades filter and then Sony the mic sounds much louder, devoid of bass heaviness. It sounds more interesting without treble heaviness. There is presence.


If a Pleiades filter is included before Pleiades V6 2DV4, mid presence decreases or high frequency emphasis can be heard.


Overall the 2 more interesting or natural sounding versions are the last 2.


It may be attempted to compare performance to the electrometer tube CV2269. Ie connecting the Pleiades V1 concept are Pleiades V6.


It looks almost unbelievable that such an interesting usable natural sound can be created with just an electron tube, 2 signal transformers, one capacitor, one bias resistor, a battery fuse and a battery.

On making battery last longer in portable electron tube microphone booster preamplifiers

Some consideration are given on  previous post.

Deriving anode voltage from electret mic-in connector

At your risk. Safety precautions must be followed. Any voltage or current can be dangerous. A fuse must be included in series with any battery for fire hazard protection.


Various Pleiades experiments including listening experiments show that a very interesting vocal sound from a microphone is created by feeding an electron tube which operates at a low or very low anode potential. Very low in this context can mean from 0V to 9V to 12V.


Example is the Pleiades V1 mic booster electron tube preamplifier operating with a CV2269 electrometer electron tube and just one AAA 1.2V battery for both filament and anode.


Another example is the Pleiades V6 operating with a vast choice of electron tubes including conventional EF183 triode connected. Still one battery can be used to power both heaters and anode and depending on which tube is used it is possible to have a portable electron tube mic booster amplifier operating with just one AA 1.2V battery (Nuvistor 2DV4) or 3 AA ie 3.6V (EF183 or Nuvistor 7586), 9V (for example 12AU7, ECC82).
Here is the schematic of Pleiades V6:
https://www.flickr.com/photos/photoulia/35858046756


Most of these examples give a phenomenally low noise performance.
Possible reasons are:
Absence of mains power supply.
Use of very clean DC battery or solar cell power.
Low electron velocities therefore low secondary emission effects by collisions with residual air molecules.
Low temperature therefore low photoemission or thermoemision on other electrodes.
(Most areas are fully explained with relevant references on previous posts).


Most of these amplifiers use Pleiades or pull up bias to make the grid less negative than the value it self assumes by electrons escaping the cathode leaving cathode positive or grid negative with respect to cathode. Cathode is positive by the remaining unbalanced (positive) protons.


Most of the above circuits, for considerations of more interesting sound, or even higher signal to noise ratio, use a deliberate lower heater voltage. This is not as unusual as it may look at first glance if one considers the underheated VF14 electron tube on the Neumann U47 microphone.


But back to subject. It should be possible to power the anode directly from a modern device. See also older posts.
In summary it is done:
By feeding cathode heater or filament to a suitable battery in series with a protective fuse.
Connecting mic to input transformer.
Capacitor couple the input transformer secondary winding to grid.
Pleiades biasing grid with a high megohm resistor from anode to grid.
Connecting anode directly to mic input of a modern device at electret mic in.
The phantom voltage of 1-2.5 volts should be plenty. The anode load resistor where amplified signal,voltage develops is the device internal resistor.
So it is.


Now for a truly portable balanced input balanced output mic booster amp it would be nice if power consumption is so low that a small battery feeding the electron tube could last for days or at least plenty of hours.


Such consideration make the use of direct filament battery electron tubes very attractive.


For example an DF97 electron tube has filament current consumption of just 25mA. Not sure yet how well can this electron tube operate at 9V anode or whether it would need more than 24V.


An electrometer triode has even less filament current at just 13mA. It can operate even at 1.2V anode electric field potential.


So it may be worth improving the Pleiades V1 schematic by features found on the Pleiadss V6.


For example replacing anode resistor with output transformer primary so that more anode voltage arrives at anode.


Perhaps using an AA battery instead of AAA.


Or optionally adding another AA battery just for the anode circuit.


If such battery holder is used with a Lithium 3.6V battery, this would create the option of a different sound with higher anode current.


A fuse should be used with any battery for fire hazard safety.


References can be found on so many posts. One of the most important will be included here which covers from the genious of the inventor of FM most on the art of controlled electron flow by a music signal ie the art of electronics of electronic engineering or engineering electronics.



Operating Features of the Audion - E. H. Armstrong

How to derive the chords of Gonna Fly Now - Bill Conti Πως προκύπτουν οι συγχορδίες του Gonna Fly Now - Bill Conti που χρησιμοποιήθηκε στην θρυλική διαφήμιση Πατιστας

See previous posts.


Στα προηγούμενα posts.

Deriving and naming the chords of the scale C major

This also applies to A minor, D Dorian as they all have all the notes natural ie the keyboard keys white.


Using these seven chords we can play almost all the musical compositions made or not made yet on the universe. We would need to start with bass C if composition is in major key or bass A if in minor key or bass D if in Dorian key.


But it is best to use the real key or scale of a composition as this dictates the atmosphere. For example E minor key.
But the same 1 3 5 7 rule apply.
All we have to do is adding the corresponding flats or sharps that define the key. For example making each F sharp (#F) if the key is E minor.


All music is referenced to bass.


And the names of chords are derived by the intervals (of the notes creating the harmony) with respect to bass.


So here it is:


C major scale:
C D E F G A B C


Chords (derived by the 1 3 5 7 ... rule)


C E G B
C major 3rd major 7th


D F A C
D minor 3rd minor 7th


E G B D
E minor 3rd minor 7th


F A C E
F major 3rd major 7th


G B D F
G major 3rd minor 7th


A C E G
A minor 3rd minor 7th


B D F A
B minor 3rd diminished 5th minor 7th


That's it.


Of Cource there is also bass code 6 for example C E A. But even this can be derived from the 1 3 5 7 9 11 13 rule if we take number 13 with respect to bass. It should end at 15 as this brings us back to C.


Exercise 1:
Try to play Gonna Fly Now - Bill Conti using the above chords.


Exercise 2:
Try to play the introduction of Old and Wise - Alan Parsons Project with these chords.

Note: on both above exercises you will play the music in the original key as these compositions are writen in the key of C major and A minor respectively. Old and Wise continues (modulates) to the key of C minor and bass descends chromatically ie semitone by semitone.


Sources:


The Bach's composition manual:


Bach Bass Rules - Bach, Niedt - Schmidt
https://normanschmidt.net/scores/bachjs-general_bass_rules.pdf


Harmony - Piston


Note:
Not sure how it is done but if chord is for example F A C E one instrument (bass for example) can play F, another instrument A, another instrument C, another instrument E. For example trumpets, human voices, strings or combinations of them.