Thank you all!
Wednesday, February 28, 2018
The Pleiades EQ
How simpler could it be?
Well in fact there is a simpler and perhaps a better way. Phil Collins can be seen placing his hands in front of his mouth to do acoustic wave cavity EQ. (Horn shape etc as it does acoustic impedance matching too, Phil is intelligent). If memory is correct it can be seen on youtube in a video showing Sir George Martin recording with his friends.
This is about a simple and very effective electronic equalizer. It is done by changing the heater voltage of the electron tube amplifying the sound.
It does great and subtle slope drop at low and high frequencies. This can be very useful to compensate for exaggerated bass or treble frequencies. Or in other words compensating for voice effort curves. Low and high acoustic frequencies are boosted when we sing softly. Also for compensating the Fletcher Manson equal loudness curves. Our brain perceives exaggerated bass and treble frequencies the more the acoustic sound pressure level is.
As the electron tube cathode cools down transconductance decreases, anode resistance increasess and this results to voltage drop at low and high frequencies at the primary of the output transformer. The output impedance of the tube interacts with the reactance of the primary winding, On inductors the reactance increases with frequency. At low frequencies the reactance is low therefore the tube is loaded and there is more voltage drop. As the tube cathode cools down and its output impedance increases we have a parametric low cut filter. A similar effect may be happening at high frequencies by the transformer capacitance or other capacitance interacting with the electron tube output impedance.
Of course it was not found this way, It was found by chance. The heater was disconnected while the anode voltage was still on. As the temperature from the 6.3V achieved temperature was droppiing initially there was an increase in gain. Possible reasons are explained on other euroelectron posts on the subject of reduced heater voltage, low noise, reduced electron cloud etc.
A convenient heater voltage in terms of low noise was found to be 3.9V. Convenient as the anode voltage of the Pleiades V6 pre preamplifier is also 3.9V. This came about as both anode and heater circuits are currently powered by 3 AA 1.2V rechargeable batteries. On the Pleiades V4 it was found that the of 3 AA batteries must be giving even lower noise than 4 AA batteries even if the gain with more voltage supply is greater.
The Pleiades V6 electron tube prepreamp is still in breadboard stage. While testing various mics and disconnecting occasionally the heater voltage it was found that the sound to listener's brain improved. More clear, more natural what one would expect from a world class EQ.
The need and success of this type of EQing become apparent when the world class Sennheiser MD21 HN microphone was tested.
Signal path, setup:
microphone - Pleiades V6 - Sony TC-D5 Pro - Sennheiser HD 580 Precision headphones
The input transformer of the Pleiades V6 has a primary inductance 0f 140mH to compensate for proximity effect on directional mics or some subtle and sometimes annoying bassyness due to Fletcher-Munson, voice effort effect etc which is apparent on all mics including pressure ones which do not have a proximity effect.
But 140mH turned to be perhaps a bit too low for the MD211 firstly tested on the Pleiades V6. It sounds great but it is on the border of sounding bass light on some types of singing.
Then other mics where tried. Very impressive were the Electro-Voice RE-15 with its low cut on and the Sennheiser MD21 HN connected at its low Z terminals.
The MD21 sounds fouler in bass than the MD211 under similar conditions. Perhaps too bassy for some type of singing registers.
It was immediately found that by playing with cathode temperature one can tailor the sound by fine tuning until it sounds almost perfect.
When the heaters are connected directly to the batteries, say at 3.9V the anode current of the triode connected EF183 (with 8Mohm anode to grid electron accelerating resistor) is 100 microamperes. This is let us say max bass and treble response, nearly flat from mic out to preamp out.
As heaters are disconnected and the temperature of the cathode gradually drops so does presence increase. Presence being max at about 20 to 30 microamperes.
Between these infinite values of anode current a value can be found where the sound is almost perfect and flat from singer's vocal chords to listener's brain.
It is not easy to adjust as one has to wait for the temperature to drop.
One way of doing it is switching to a series to the heaters 9 ohm resistor. Using 9 ohms the anode current will finally settle at the low extreme of 20 microamps.
While a microamp anode current meter needle is monitored, once the sweet spot is heard one can record the value of the anode current at that instant.
Then this value of anode current can be achieved by adjusting a 10 ohm series wire wound rheostat in series with the electron tube cathode heater circuit.
Of course a variable resistor could be connected between anode and output transformer. Compensating by another ganged resitor for reduced Vb voltage will the same EQ effect be induced? Or are additional effects into play when electrons get loose?
Pleiades ideas, concepts, schematics are open source.
References:
Pleiades V6 Schematic
Flat frequency Response from Actor's, Singer's Vocal Chords to Listener's Brain, Sound Picture Recording and Reproducing Characteristics - Loye, Morgan - Journal of the Motion Pictures Sound Engineers
Operating Features of the Audion - E.H. Armstrong (for explanation on how an electron tube self biases it self negatively internally. The Pleiades V6 uses an 8 Megohn resistor from anode to grid to counteract externally this internal effect and make the electron tube operate with only 3.9 volts at the anode.)
Pleiades ideas, concepts, schematics are open source.
Tuesday, February 27, 2018
Sennheiser MD21, MD211 N and Pleiades V6 or Pleiades filters to Sony TC-D5 Pro
The MD21 is an amazing microphone (the MD21 HN was used from its low impedance out). On these experiments it seems to have sounded even better than the MD211. All it needs is a shunt inductor around the value of 140mH (there is already a shunt inductance from the internal transformer of HN which should be around 800mH?, so an MD21 should possibly be terminated with a lower inducatnce than 140mH) and it is ready to possibly sound better than mics with 4 more zeros for singing or instruments.
Connected to the Pleiades V6 prepreamp it sounded amazing as the primary inductance is 140mH. With 140mH there is an almost perfect balance for male voice without bass heavy response. Amazing mid and treble detail too. Amazing loud sound with the V6 prepreamp singing with it.
The MD211 sound great too but is a bit more bass light terminated with 140mH.
So it was time to experiment by terminating it by various values of inductance and feeding the Sony TC-D5 directly.
With 160mH-330mH more bass is there.
The MD211 has amazing treble detail, more than the MD21.
But the MD21 still sounds better?
Connected to the BBC 200Ohm to 600Ohm step up transformer feeding the TC-D5 it sounded amazing too.
When the chain was mic - Pleiades V6 - Sony TC-D5 Pro the sound was with more treble detail, more loud, less noise if there was any noise.
On previous Pleiades V6 experiments many more great mics were tried on male singing voice. Such as MD441 U3, Re-15, Paso 980, SM58 Mexico, Unidyne III (vintage SM57), Grampian ribbon GR1/L, D190.
Although it is all subjective opinion the mics that really sounded as there was no mics , no electronic chain amazing natural sound were the;
Re-15 with its low cut and
MD21
The Grampian too is amazing, see the Pleiades V6 signal path needed on a previous euroelectron post for 2-3in mic distance. Amazing deatail.The MD211
The 635a, it could be 3rd.
The Unidyne III sounded great too.
The Paso 980.It is a very natural sounding mic.
The MD441. It can be much more up on the list. It is more difficult to find the right low cut turnover frequency according to mic distance to compensate for the proxiity effect.
D190
It is very interesting how low noise the battery powered Pleiades V6 electron tube booster preamp is.. When nothing is connected one hears very little hiss. Making you wonder, is it on? Then the RE-15 is connected and you get scared by how loud, clean, natural, low noise it sounds. Same for the other mics.
On most of these mics there was almost no s problems at all even though the treble detail was amazing....
Signal path, setup:
mic - Pleiades V6 - Sony tC-D5 Pro - Sennheiser HD580
or
mic - Pleiades filter - TC-D5 Pro - HD580
or
mic - BBC 115mH:382mH - TC-D5 Pro - HD580
Reference:
Pleiades V6 schematic
Why does light travel
Possibly because a varying magnetic field creates a varying electric field (law of induction) a varying electric field creates a varying magnetic field and so forth....
But it may be much simpler to think of electrons as jealous little creatures.For example those vibrating in the sun make those inside a chair to vibrate too because they are jealous. The electrons in our eyes vibrate too because they are jealous and we see the chair.
References:
Conceptual Physics - Hewitt
The Feynman Lectures on Physics
Feynman on youtube
The great thing about class A amplifiers...
apart from the great, smooth sound is that electrons travel while moving back and forth so they don't get bored.
In interstage transformers too.
In input transformers too, if there is no coupling capacitor, there is cathode emission grid current.
When electrons dance to the music inside the primary of a signal transformer, it is not the same electrons dancing to the music inside the secondary. Or is there a tunneling quantum mechanic effect?
Perhaps it does not matter, the electromagnetic wave travels anyway from microphone to loudspeaker. From producer's brain to listener's brain?
A fairytale showing the travel of an electron when the singer starts singing
Electron tubes talking etc.
Monday, February 26, 2018
How to have a great vocal sound on the Grampian GR1 or GR2 ribbon microphone
It is a brilliant mic. But it is low output.
This post is about the GR1/L which has an even less voltage output. It can be made to sound loud, amazing, with the most extended, detailed and sensitive, loud response imaginable. with no s problems, amazing transient response. Silk smooth sound.
What is needed is an ultra low noise pre amplifier.
The Pleiades V6 battery powered electron tube preamplifier with deliberately underheated heaters as on the Neumann U47 internal VF14 preamplifier has been found to be ideal.The Pleiades V6 schematic is open source as everything Pleiades.
A preamplifier input transformer step up ratio of 1;30 works great as the impedance of this mic is 30 ohms.
If one wishes to further improve the overall signal to noise ratio (from singer's vocal chords to listener's brain) the singer has to be close to the mic.
The proximity effect would unacceptably increase bass from say 1KHz and downwards at 6 dB per octave. SO we need a complementary high pass filter of 6dB per octave rising up to say 1 KHz.
This can be done by a Pleiades filter ie a shunt inductor connected to the output of the mic. This is the same technique used on the great RCA ribbon mics, the great Electro-Voice RE-15 moving coil etc.
For real close singing to the mic an inductance as low as only 3mH seems suitable and gives amzing sound.
So the V6 preamplifier input transformer could be arranged to have a primary inducatnce of say 3mH. This means very few turns. only 10? for a Magnetec 070 core? The secondary turns would only be 300 making it a joy to wind.
Another option is to use a more ordinary 1:10 input transformer on the preamp.
ANd create the total of 1:30 by just adding an inbetween 1:3 impedance converter transformer. Again the primary inductance can be made low with a few turns to cut as much bass is needed for flat frequency response from singe's vocal chords to listener's brain.
The low inductance electromagnetically damps the ribbon (Lenz's law or conservation of energy law) so pops are almost off. But still we should not abuse such a great and sensitive microphone.
The above techniques may also be used for other ribbon microphones. Of course they are very suitable for world class moving coil microphones such as RE-15 for example making with them sound even more unbelievable. Same for pressure moving coil mics such as MD21, MD211, M55, F-96 etc.
The Grampian ribbon mic was also used to make amazing recordings of ensembles, or rockbands etc. It was used picking up all instruments. It sounds both great as a mono mic or a blumlein pair. The input transformer inductance has to be much greater as now the distance involved is much greater. An amazing signal path is:
Grampian GR1/L pair - Sowter 1:20 transformers - Ferrograph Series 6 electronic valve reel to reel recorder
At 7.5 ips it is hard to believe how well cymbals from the drums are reproduced. The electric bass sound in the room. The organ with SE PCL86 amplifier and Pleiades rotating speaker hung from the ceiling. The microphone captures the sound as our ear does, no need for any EQ. Broad band panel absorbers such as Pleiades absorbers would have improved the reverberation of LF frequencies while recording. More information on this amazing setup with just a couple of electron tubes from mic to tape can be found on another euroelectron post through google search. A great recording of flute and classical guitar was also done with the mics inside a church, Pavane -Gabriel Faure.
References:
Flat frequency response from singer's, actor's vocal chords to listener's brain, Sound Picture Recording and Reproducing Characteristics, Lowe, Morgan - Journal of the maotion picture sound engineers
Pleiades V6 schematic
Neumann U47 schematic
The Feynman Lectures on Physics
Coil Design and construction manual - Babani _ BP160
Analog Simulation of magnetic tape music recording part ?
Perhaps a good idea would be to treat the interstage saturating transformer in the same way as on an electron tube class A (electrons flowing all the time) biased amplifier.
So arranging the DC electron current to be such that we are near the mid point of the B H magnetic hysterissis curve of the core material used.
Also arranging low inductance so that coil be current fed rather than voltage fed. Just like electron tubes driving magnetic reel to reel recorder heads with their high output impedance creating a constant current source with respect to frequency. So just like tape recording ie a rising recording voltage with respect to frequency. This is done automaticaly as the reactance of a coil increases with frequency so impedance increases and there is less shunt load across the electron tube output. So less voltage drop therefore rising response with increasing frequency. This is exactly the principle used on Pleiades filters for high pass EQ on microphones for compensating for proximity bass increase and other effects.
Constant current gives the chance at all the frequencies to saturate at high levels.
Would this instantenious peak limiting method resemble or simulate well enough the miracle of magnetic tape music recording?
Perhaps some more stages may be added to the Pleiades V6 battery electron tube preamplifier. The derivative amp will be possibly called V7.
The amplifying stage after the interstage transformer would do mathematical integration or high cut filtering at 6dB per octave for de emphasis. Same as on reel to reel tape playback pre amplifiers.
Sunday, February 25, 2018
Pleiades Passive Prepreamp
On the next euroelectron post on impedance matching from the MD211 N microphone to the Sony TC-D5 microphone input using just a BBC 1:2 step up transformer between the 2 equipment.
MD211 N microphone BBC (1:2) transformer TCD5 impedance matching
Here is a relatively simple experiment to show how important is impedance matching.
1st setup:
Sennheiser MD211 N - Sony TC-D5 PRO - Sennheiser HD580
It does not sound loud and it sounds bass heavy or unfocused to listener's brain. Possible hiss.
2nd setup, signal path;
MD211 N - BBC step up transformer, 1:2, 115mH:382mH - TC-D5 PRO - HD580
It sounds fantastic. Loud, not bass heavy, natural, world class, correct to listener's brain. Great signal to noise ratio as the Sony REC level potentiometer does not have to be at 10 for full modulation but at say 7.
Looking at the whole system form singer's vocal chords to listener's brain it is worth noting how louder it sounds.
Not as loud or sensitive as when a Pleiades V6 active battery electron tube prepreamp is connected between mic and Sony recorder but the sound is there. Much simpler, passive ie no power consumption. No electron tube. Less weight A 1:2 transformer can be made with a small ring core such as Magnetec 073, fit inside a Neutrik barrel XLR module. One can have a world class sound with a passive prepreamp booster transformer that fits inside the pocket.
Some measurements;
The Sony TC-D5 PRO input impedance is measured 4.5Kohm with an escort ELC-120 LCR meter.
When the BBC transformer is connected, the new input impedance reads 360Ohm.
When the impedance of the BBC transformer is measured (transformer unconnected), primary is 220Ohm, secondary is 800Ohm.
its winding inductance measurements are, primary to secondary:
115mH to 382mH
so by division and then taking the square root this should be a 1 to 1.8 transformer, or the impedance of the MD211 should be increased from 200ohms to 650 ohms. This is found by multiplying 200 times 1,8 times 1,8
The low primary inductance ie 115mH cuts some bass thereby reducing bass heaviness due to Fletcher- Manson, Voice Effort curves etc and creates flat frequency response from singer's vocal chords to listener's brain.
Only problem was that this particular BBC transformer was probably not made for microphones. It is not encapsulated or mu metal shielded etc and there was buzz pickup from environmental RF or magnetic field noise.
If one uses a mumetal or nanocrystalinne tape wound core with so relatively few turns needed to get those small inductances it could be made very easily.
One could immediately have a world class, state of the art sound that should beat almost anything.
The BBC transformer used is the LL/210A and was bought long time ago from Canford UK.
reference:
Flat frequency response from singer's vocal chords to listener's brain, Sound Picture Recording and Reproducing Characteristics - Loye, Morgan - Journal of the Motion Picture sound engineers
Thursday, February 22, 2018
Η Κανελινα έμαθε να παιζει οποιοδηποτε μουσικο κοματι με το αυτί - εγκεφαλο και με τα δυο χέρια η ποδια
Ειναι πολυ εύκολο.
Ξεκινάει να βρει πειραματικά την μελωδία διορθώνοντας τα λάθη με το αυτί και τον εγκεφαλο της.
Μετα ξεκινάει να βρει το μπαςο. Το αριςτερο χέρι η πόδι. Δεν ειναι τοςο εύκολο. Αλλα στην χειρότερη περιπτωςη εχει να διαλέξει στην τύχη ποια απο τις εφτά νοτες ειναι. Η ποια απο τις 12 νοτες (12 μαζι με τις υφεςεις η διεςεις) ειναι αν δεν γνωρίζει την κλίμακα στην οποία ειναι γραμμένο το κοματι. Δοκιμάζει πια νότα ταιραιαζςι με την μελωδία.
Μετα προσθετει νοτες στο δεξί χέρι με βαςη τον κανόνα 1 3 5. Αν πχ το μπαςο ειναι Ντο, προσθέτει Μι και Σολ.
Κάποια κοματια έχουν και πιο εκλεπτυσμένες συγχορδίες οπως 6ες, 7ες, 9ες. Με τα παραπάνω διαστήματα 6ης, 7ης, 9ης βάζουμε και το διάστημα της 3ης. Πχ μπαςο Ντο, το Σι απέχει 7 φυσικές νοτες, και το Μι ειναι η 3η. Αρα η συγχορδία ειναι Μι Σολ Σι και μπαςο Ντο. Βάλαμε και την 5η που ειναι Σολ. Η αυτη ονομάζεται Ντο7 η Ντο μεγάλη έβδομη, στα αγγλικά C major seventh η Cmaj7 η με τον κώδικα Μπαχ C7 η Ντο7.
Μουσικο παραδειγμα.
Imagine - John Lennon
Το κοματι ξεκινάει με Ντο μπαςο. Βάζουμε στο μυαλό μας 3, 5 δηλαδή τις νοτες Μι, Σολ.
Πράγματι το κοματι εχει στο δεξί χέρι Μι με Σολ μετα Ντο, Μι με Σολ μετα Ντο. Μι με Σολ με Σι μετα Ντο....
Στη συνεχεια το μπαςο ο συνθέτης αποφάσισε να ειναι Φα. Με το κανονα 1,3,5 έχουμε Φα, Λα, Ντο.
Για να μην μετακινηθεί πολυ το χέρι, έχοντας οςο το δυνατόν μικρότερη αλλαγή ο συνθέτης χρησιμοποίησε τις νοτες αυτες ως εξης. Φα μπαςο, και δεξί χέρι Φα με Λα, κατω Ντο, Φα με Λα, κατω Ντο ...
Όμοια για καθε άλλη νότα μπάσου.
Πηγη:
Οδηγίες του Μπαχ προς τους μαθητές του:
http://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
Canelina has learned to play any music piece on the piano by ear - brain with both hands or feet
It is easy.
First the melody is learned by trial and error.
The the bass is learned by trial and error . It is much more difficult but the good news is that the notes are just 7, 12 of the scale is not known, so Canelina can even try in random 7 notes until she finds the right one that goes correctly with the melody.
Then the 3rd and 5th are added for harmony.
Some chords contain the more refined intervals of 6th, 7th, 9th etc. but with most of the the 3rd is taken too.
An example song.
Imagine - John Lennon
Bass is C. Right hand is derived from 1,3,5. So the notes are C, E, G. In fact the right hand plays E,G C, E,G C E,G,B C
Then bass is F. The 1,3,5 rule gives F A C. In fact the right hand uses these notes but plays them with the least change from C,E,G. So it plays F,A C F,A C.
And so it goes.
Reference:
Bach bass rules:
http://normanschmidt.net/scores/bachjs-general_bass_rules.pdf
MD211 or SM57 to Pleiades V6 to Sony TC-D5 pro
It was decided to connect the output of the Pleiades V6 pre preamp to the low impedance input of the Sony TC-D5 pro. The TC-D5 mono option was switched on so that sound could be heard on both headphone drivers.
Signal path, setup
Male singing voice - microphone - Pleiades V6, 140mH transformer primary, 8MΩ from anode to grid, 22nF grid coupling capacitor - Sony TC-D5 pro on mono - Sennheiser HD580
The Pleiades V6 (in breadboard stage) electron tube pre preamplifier was powered by 3 AA rechargeable batteries. So anode voltage was roughly 3.9V. A variable wirewound series resistor to heaters was used to further reduce the cathode temperature.
When the heater voltage was 3.9V the anode current was 100μA. When the rheostat was at 9Ω the heater voltage would have been 2.5V? and anode current was measured to be 40μA.
Firstly the Sennheiser MD211 was used at 0 to 2in.
The sound was amazing. As if one was recording in the finest recording studio. All the fine detail one can imagine. Very low noise. High output. The recording level potentiometer on the Sony TC-D5 pro was at position 3 out of 10 for full modulation even with a very soft singing voice. A behaviour similar to connecting a high output world class condenser mic such as an AKG C24. When the gain was increased on the TC-D5 pro sounds from dozen of meters away could be heard with prestine detail, birds etc. There was a nice balance of ambient sound frequency spectral content with no bass of rumble exaggeration to listener's brain. It seems the 140mH primary inductance of the mic input transformer is a nice choice. In fact it almost happened by chance. It is the transformer that did not make it as the output transformer. The turns ratio of both transformers used is 1:10.
The Sennheiser MD611 M (medium impedance) was connected too. It sounded loud, somewhat less low noise, and somewhat less refined. Nevertheless it was a nice sound.
The SM58 Mexico was then connected. It sounded fine. An optimum distance was 4-5in. At less than this the sound was becoming bass heavy, and at larger than this thin, (proximity effect). When increasing gain the ambient noise only consisted of very high frequencies and hiss (proximity effect again). There was a little handling noise.
The MD 211 N sounded so refined!
Most listening tests were done with just Ia=40μA, ie the electron tube further underheated. When the EF183 triode connected electron vacuum tube is further underheated (when the anode current is less than say 70μA and more than 40μA) the sound is even more interesting. As if one gets with a microscope to even more detail. Louder too. There may be an euphonic distortion too? Or is it that at 100μA the sound is so clear that it is not natural. Also at 40μA is some of the high end and low end is possibly reduced making the voice sounding more correct, with a more flat frequency responce from singer's vocals chords to listener's brain.
Canelina the cat and the patient tortoise handshaked each other for the Pleiades V6.
References:
Pleiades V6 schematic
On preserving electron tube transconductance with only 3V at the anode - euroelectron blogspot
Flat frequency response from actor's, singer's vocal chords to listener's brain, Sound picture recording and reproducing characteristics - Loye, Morgan - Journal of the Motion Pictures Sound Engineers
Ενα ωραίο βιβλίο προσεχώς απο τον Al Schmitt που ηχογράφησε το Aftica - Toto, Henry Mancini κτλ
Al Schmitt on vocal and instrumental techniques.
Ο παντα καλοντυμένος Al Schmitt που αγαπάει τα μικρόφωνα και τα διαλέγει αντί για EQ η compression.
Η Κανελινα και η υπομονετική χελώνα σκευτονταν να προ παραγγείλουν το βιβλίο.
https://www.amazon.co.uk/gp/offer-listing/1495094510/ref=sr_1_1_olp?ie=UTF8&qid=1519311259&sr=8-1&keywords=Al+Schmitt
Απόσπασμα συνέντευξης του Al Schmitt
https://www.bobbyowsinski.com/recording-engineers-handbook-al-schmitt-excerpt.html
A great book is coming up by Al Schmitt on using microphones
All Schmitt on vocal and instrumental techniques
https://www.amazon.co.uk/gp/offer-listing/1495094510/ref=sr_1_1_olp?ie=UTF8&qid=1519311259&sr=8-1&keywords=Al+Schmitt
By the smartly dressed sound engineer who has recorded Africa - Toto, Henry Mancini and so much more.
A man who loves microphones and chooses them instead of EQ or using compression.
Canelina and the patient tortoise at last learn how the Henry Mancini sound is made
On the next euroelectron fairytale in Hellenic language.
Summary:
Canelina and her friend learn a lot by watching the interview of the man who recorded Mancini, sound engineer Al Schmitt
Η Κανελινα και η υπομονετική χελώνα επιτέλους έμαθαν πως γινεται ο ήχος Henry Mancini
Η Κανελινα ανέβηκε πανω στην υπομονετική χελώνα για να μην την περάσουν για γάτα και να ειναι πιο ψηλή και πήγαν σε ενα ωραιο μεγάλο μουσικο κατάστημα της Αθήνας.
Ήθελαν να πάρουν μια ωραια χρωματική φυσαρμόνικα.
Οταν ανέφερε τον ήχο του Henry Mancini, ο υπεύθυνος της είπε οτι ποτε δεν θα καταφέρει να το πετύχει. Η Κανελινα σχεδόν βάζοντας τα κλάματα ρώτησε, "ξέρετε τι μηχανήματα χρησιμοποιουςαν; Η απάντηση του υπεύθυνου ήταν, "που να ξέρω;"
Οταν έφυγαν απο το μαγαζί, η υπομονετική χελώνα παρηγορούσε την Κανελινα λέγοντας της να θυμηθούν τα λογια της ψυχοθεραπεύτριας κουκουβάγιας. "Αυτα που λένε οι άλλοι χαρακτηρίζουν αυτούς", "Τον εαυτό τους".
Ο υπεύθυνος είχε επίσης πει στην Κανελινα που τελικά αγόρασε λιγο χαρτί παρτιτούρας οτι για να γράψεις πρεπει να εχεις έμπνευση. Αντί να πει οτι γραφοντας ερχεται η έμπνευση. Η οτι τρώγοντας ερχεται η όρεξη. Η Κανελινα σκούπισε τα δάκρυα της, λέγοντας μεςα της τα λόγια της ψυχοθεραπεύτριας κουκουβάγιας στο δάσος.
Μετα απο καιρό κατι ομως έγινε ξαφνικα και σχεδόν τυχαία έμαθαν πως γινεται ο μαγικός αυτός ήχος. Για παραδειγμα το Moonriver - Henry Mancini απο το σάουντρακ της ταινιας Breakfast at Tiffany's.
Moonriver - Mancini - YouTube
https://m.youtube.com/watch?v=2Ed07ogWgiw
Θυμήθηκαν τα λόγια ενος δασκάλου τους στη μουσική, του Τερυ που έλεγε, "οταν ρίχνεις στην μπάλα πέος τη σωστή κατεύθυνση κάποια στιγμή θα μπει τρίποντο".
Και τελικά συμφιλιωμένη η Κανελινα απέκτησε φιλικές σχέσεις με το μουσικο κατάστημα, ένταση παντα ευγενική, με την βοήθεια του βιβλίου του Καρνεγκι, και τώρα όλοι την εξυπηρετούν και εκεινη τους κανει να αισθάνονται ομορφα όντας σημαντικοί. Ας πάμε ομως στο θέμα μας
Άκουγαν λοιπόν Kiss FM και μπαίνει το πανέμορφο τραγουδι Africa - Toto.
Η Κανελινα σταμάτησε οτι έκανε και καρφωμένη στο ραδιόφωνο άκουγε. Όταν τελείωσε πετάχτηκε και είπε: "να μάθουμε πως ηχογραφήθηκε!"
Μπήκαν λοιπόν στο Ίντερνετ ψάχνοντας στο Google, classic tracks Africa Toto how it was produced.
Για καλη τους τύχη το mix online είχε κανει ειδικό άρθρο για το τραγουδι με συνεντεύξεις των συντελεστών μουσικών και του μηχανικού ήχου Al Schmitt.
Εκει έμαθαν οτι ο Al Schmitt είχε ηχογραφήσει και τα κοματια του Mancini.
Απο εκει και πέρα τα πράγματα ήταν πιο ευκολα. Έβαλαν στο YouTube, Al Schmitt interview και αμέσως βρήκαν μια συνέντευξη σε ενα Ίντερνετ κανάλι οπου ο Al Schmitt αναφέρει και για τον ήχο στις ηχογραφήσεις του Mancini.
Έμαθαν οτι ο Al Schmitt απο πολυ μικρο παιδάκι είχε επαφή με στούντιο ηχογραφησης αφου είχε ο θείος του.
Έμαθαν οτι για στις ηχογραφισες του ο Al χρησιμοποιουσε συνηθως 5 θαλάμους αντιχησης. Έμαθαν επιτέλους τι ειναι ο θάλαμος αντιχηση.
Ο θάλαμος αντιχησης, reverberation chamber η (echo room) ειναι ενα δωματιο συνηθως σε υπόγειο, οχι απαραίτητα μεγάλο με ανακλαστικες επιφάνειες. O Al είπε οτι το περνούσαν με αρκετα χέρια βερνίκι γόμα λακας για να γίνουν οι επιφανείς ακομα πιο σκληρές, (λείες;) και ανακλαστικες. Εκει έστελναν τον ήχο απο την κονσόλα ήχου με καλώδιο. Μεςα βρισκόταν ενα μεγάφωνο για να παιζει τον ήχο. Το δωματιο αντιχούσε. Και ενα μικροφωνο έπιανε τον ήχο και τον έστελνε με καλώδιο πιςω στην κονσόλα για να ενωθεί με τον απευθείας ήχο.
Στην Ελλάδα είχαμε 3 echo rooms στα υπόγεια της Columbia στη Ριζουπολη. Ενα στο παλιότερο στούντιο 3 του 1933 και 2 κατω απο τα στούντιο 1 και 2. Ειναι πολυ εύκολο να ακούσουμε τον ήχο ακουγοντας οποιαδήποτε ηχογραφιςη του Καζαντιδη για παραδειγμα.
Δωματιο αντιχησης εννοείται ειχαν φτιάξει μετατρέποντας μια αποθήκη, στο καλυτερο στούντιο στον πλανήτη. Το 30th street studio της Columbia, CBS (Columbia Broadcasting System) στη Νεα Υορκη. Εκει ηχογράφησαν Stravinski, Simon and Garfunkel, Bob Dylan, Barbara Streisand, Leonard Bernstein, Glenn Gould, Miles Davies... Ήταν τοςο ξεχωριςτος ο ήχος που μηχανικοί ήχου απο το καλυτερο στουντιο ηχογραφηςης της Αγγλιας, το Abbey Road studios, πήγαν εκει για να μάθουν και έπειτα να ηχογραφήσουν πχ τους Beatles, Pink Floyd κτλ. Λεπτομέρειες αναφέρει ο Frank Laico που ήταν μηχανικος ήχου στο στουντιο της Columbia στην Νεα Υορκη το οποιο ήταν μια εγκαταλελειμένη ορθόδοξη Αρμένικη εκκλησία.
Ο Al Schmitt χρησιμοποιούσε 5 δωμάτια αντιχησης. Έστελνε λίγα όργανα στον καθένα.
Στη μίξη του ήχου έβαζε έναν θάλαμο μονο στο αριστερό κςναλι η ηχείο, έναν θάλαμο στο δεξί. Έναν στο κέντρο (δηλαδή και στα δυο ηχεία) και δυο θαλάμους καπου ενδιάμεσα.
Επισεις έμαθαν οτι ο Al Schmitt σχεδόν παντα χρησιμοποιούσε μικρόφωνα παντοκατευθυντικα (πίεσης) επιβεβαιώνοντας τα πειράματα της Κανελινας και της υπομονετικής χελώνας οτι ακούγονται με πολυ φυσικό τροπο.
Η Κανελινα πετάχτηκε απο τη χαρά της.
Και μαζι με την υπομονετική χελώνα, το γάτο με την πραςινη κορδελα και την ψυχοθεραπεύτρια κουκουβάγια έτρεξαν να πουν τα νεα στους σοφούς γλάρους στην παραλια.
Και όλοι χόρεψαν και τραγουδηςαν κάνοντας μπάνιο, Moonriver - Mancini ακουγοντας και την προτελευταία μεγάλη έβδομη συγχορδία, κατω απο το φως του Ηλιου που δεν αφηνει καμια σκια στην αλήθεια.
Πηγη·
Al Schmitt interview - Pensado's place - YouTube
https://m.youtube.com/watch?v=tcwGXQI1U_4
Συνομιλία με τον μηχανικό ήχου Στέλιο Γιαννακοπουλο (πχ στους δίσκους του Μανου Χατζιδακι) για το στούντιο της Columbia στην Ριζούπολη, Αθήνα.
Temples of Sound - Cogan, Clark
Studio Stories - Simons
Frank Laico interview - AES - YouTube
How to win friends and influence your environment - Dale Carnegie - PDF
Wednesday, February 21, 2018
I use omni mics almost on everything - Al Schmitt
Leakage is your best friend. That's what makes things sound big.
https://m.youtube.com/watch?v=tcwGXQI1U_4
On around 25:50
How to never het tired, Πως να μην κουραζόμαστε ποτε
A fantastic trick is to stop a task for a break just before feeling tired.
Ενα φανταστικό κόλπο ειναι να σταματάμε οτιδήποτε κάνοντας διάλειμμα μόλις πριν αισθανθούμε κούραση.
Reference, πηγη:
How to stop worrying and start living - Dale Carnegie - PDF
Έξω η Λύπη - Ντέιλ Καρνεγκι
Sennheiser MD211 with Pleiades V6 pre preamplifier
The Pleiades V6 is in breadboard (experimental board). The EF183 electron vacuum tube is powered by 3.9V and even less voltage for the heaters as there is a wirewound series resistor in the heater circuit of the cathode. An 8ΜΩ anode to grid electron accelerating resistor was used making battery operation possible. The input and output transformers are made using the Magnetec 070 nanocrystalinne ring core and are described on previous euroelectron posts. The usual green Altec input transformer was also pluged in and was somehow bass heavy as its input inductance is 400mH. This should be great for drums but not for voice as voice effort curves, Fletcher Manson Curves etc have to be compensated for flat frequency responce from singer's vocal chords to listener's brain.
Signal path, Setup:
Male singing voice at 0-2in from the microphone - Sennheiser MD 211 N microphone - Pleiades V6 preamplifier - Realistic disco mixer at mic in - Sennheiser HD580
What an amazing microphone! So small yet when it is connected birds on the trees can be heard so clearly.
It is great that this mic has a so smooth, without reasonances curve. And being extending to 20KHz.
Of course underheating reduces the high end of amplification as well giving more presence. Underheating seems to increase the output resistance of the electron tube so external components or even stray capacitances have more effect on the frequency responce.
Of course no pops or s problems even just next to the mic.
With the Altec transformer the sound was somehow bass heavy for voice as expected. By further reducing the heater voltage from 3.9V to 2.5V and thereby the anode current from 90μA to 30μA the sound was big without bass heaviness.
Using the 140mH Pleiades input transformer at the very low heater voltage the sound was in the verge of becoming bass light. It was full at 3.9V heater voltage. And a sweet spot must be between 40μA and 60μA. For some reason an underheated cathode makes a more full and easy perception of sound to listener's brain. Is this a main reason why the U47 sounds the way it does with the VF14 electron tube or radio (TV) valve underheated by Georg Neumann?
Perhaps the Pleiades V6 prototype should have a wirewound cathode temperature adjusting resistor for adjusting for optimum sound depending on singer, song, arrangement, recording environment etc.
The wire wound resistor value for 30μA anode current when Vb=3.9V is 9Ω. So a 10Ω wirewound or multi turn wirewound potentiometer may prove very useful. When an electron tube is underheated, it is very interesting and a joy to wait at least 47? seconds for subtle hiss to change to more hiss to more sound, to bird ambient sound like on expensive cathode underheated electron tube condenser microphone internal preamplifiers.
References:
Pleiades V6 Schematic
Flat frequency responce from actor's, singer's vocal chords to listener's brain Sound Pictures recording and reproducing characteristics - Loye, Morgan - Journal of Motion Pictures sound engineers
On preserving transconductance of electron tubes (on an anode potential as low as 3V) - euroelectron
How was the Henry Mancini sound made? Πως παράγονταν ο ήχος του Henry Mancini;
Of course the arrangement plays a major part.
Οπωσδήποτε η ενορχήστρωση παιζει σημαντικότατο ρόλο.
Another reason is that 5 live reverberation chambers were used. One panned left, one right, one middle, and 2 in between.
Άλλος λόγος σημαντικός ειναι οτι χρησιμοποιούνταν 5 δωμάτια ηχους, echo rooms, η echo chambers υπόγειοι. Στο στούντιο ηχογραφισης στην Columbia στην Ριζούπολη, είχαμε 3 echo rooms. Τα χάσαμε, δεν πειράζει. Ο Al Schmitt μηχανικος ήχου στις ηχογραφήσεις του Henry Mancini οπως και Africa - Toto, εξηγεί πως φτιάχνονται. Ο Les Paul ήταν πρωτοπόρος στην χρήση τέτοιων δωματίων. Ακομα και στην τεράστια ορθόδοξη εκκλησία οπου ηχογραφήθηκαν, Bob Dylan, Barbara Streisand, Sound of Music (Μελωδια της Eυτυχίας), Kind of Blue - Miles Davies, Take Five - Dave Brubeck - Leonard Berstein, Glenn Gould κτλ χρησιμοποιούσαν και μια μικρη αποθήκη για echo chamber.
Recording engineer Al Schmitt talks about it on the referenced interview. He explains too how live chambers were made. Les Paul was a pioneer of reverberation live chambers. Evan the huge Orthodox Church used by Columbia, CBS in New York for artists mentioned on the above paragraph had a very small echo chamber and it was a major secret of the sound.
Reference:
Producer and Engineer Al Schmitt - Pensado's place - YouTube
https://m.youtube.com/watch?v=tcwGXQI1U_4
Temples of Sound, inside the great recording studios - Cogan, Clark
Frank Laico AES interview - Yiutube
Tuesday, February 20, 2018
Η Κανελινα έκλαψε ακουγοντας το Africa - Toto
Η Κανελινα έβαλε τα κλάματα ακουγοντας στο ραδιόφωνο το φανταστικό τραγουδι Aftica - Toto γιατι της άρεσε πολυ.
Επισεις γιατι δεν μπορουςε να καταλάβει πως έκαναν την κυρια φωνη να ακουγεται τοςο ωραια και γεμάτη, εξωπραγματική.
Οι σοφοί γλάροι της εξήγησαν οτι στο studio ηχογραφησης έκαναν κατι που δεν μπορεί να γίνει στη φυση.
Ο τραγουδιστής τραγουδάει τρεις φορες πανω στον εαυτό του.
Τι σημαίνει αυτο; ρώτησε όλο αγωνία η Κανελινα.
Τραγουδισε μια φορά. Μετα ακουγοντας το κοματι, ιςως και την προηγούμενη φωνη, ξανατραγούδησε το ίδιο. Και μετα ακουγοντας το κοματι, ιςως και τις προηγούμενες φωνές, ξανα το ίδιο.
Η Κανελινα πετάχτηκε απο τη χαρά της.
Και όλοι μαζι χόρεψαν και τραγουδηςαν Aftica - Toto στην παραλια κατω απο το φως του Ηλιου που δεν αφηνει καμια σκια στην αλήθεια.
Πηγη:
Recording Toto's Africa - Classic Tracks - Mix online
https://www.mixonline.com/recording/classic-tracks-totos-africa-375305
The lead vocals on Africa - Toto are triple tracked
Reference:
https://www.mixonline.com/recording/classic-tracks-totos-africa-375305
How was the masterpiece Africa - Toto produced?
On Mix magazine, classic tracks, Toto's Africa
https://www.mixonline.com/recording/classic-tracks-totos-africa-375305
A big sounding Recording setup
It sounds big even on the tiny speaker of the Sony TC-D5.
Signal path:
Oberheim OB-XA for bass
Yamaha DX7ii for pads with Pleiades tuning
Gelosso crystal mic for female vocals
DX200? As drum machine
All connected to the FBT personal 1002 or 2002 electron tube PA with tape echo
One output of the PA is fed to 4 multiple full range loudspeakers on all corners of the room
Another output from the PA is fed to a 4031-B cinema engineering equalizer to cut treble
Then an RCA BA-6A is connected
And then the signal is passed on to the cassette recorder
So for example for the pads only the tape recorder receives many signals.
1 the direct of the DX7 through FBT
2 the delayed DX7 throughly the tape echo of FBT
3 the FBT DX7 sound fed to the room and (leakage) picked up by the vocal mic which feeds FBT (therefore the tape recorder too and all the other mentioned paths) in an endless acoustic negative feedback loop!
Reference:
Words don't come easy cover
Οταν εχεις λίγα πιάτα,...when you have a few dishes...
εχεις λίγα πιάτα να πλένεις.
there are only a few dishes to wash.
Monday, February 19, 2018
Η Κανελινα και το ΠΣΙΠΣΙΝ η ΚΠΙΣΝ
Ετςι λέει η Κανελινα χαϊδευτικά το ΚΠΙΣΝ.
Σκεφτονταν με την υπομονετική χελώνα αν θα ήταν ωραια ενα ελληνικο τραγουδι να ξανακάνει τον γύρο του κόσμου.
Θα μπορουςε να ηχογραφηθεί στο ΠΣΙΠΣΙΝ; Για να συμβεί αυτο απαιτούνται έτη προσπάθειας απο πολλούς ανθρωπους.
Θα μπορουςε να γίνει αυτο με απόλυτη διαφάνεια και το ΠΣΙΠΣΙΝ κάποια στιγμή ακομα και να εκπαιδεύει μουσικά;
Αν ενα ελληνικο τραγουδι έκανε το γύρο του κόσμου μετα δεν θα προλάβαιναν να διαχειρίζονται τα studio ηχογράφησης.
Η Κανελινα σκευτονταν οτι θα αυξανόταν ο τουρισμός της χώρας.
Θα μπορούσαν η Κανελινα και η υπομονετική χελώνα να ζητήσουν τη βοήθεια του Βαγγελη Παπαθανασιου;
Αν ολα πάνε καλα θα μπορουςε να γίνει κσι ενα ωραιο μουσείο ηχογραφησης; Το πρώτο στην Ευρώπη αν οχι παγκόσμια.
Για ολα αυτα οπως και για τα παντα δεν χρειάζονται χρήματα, χρειάζεται θέληση.
Η υπομονετική χελώνα είπε στην Κανελινα, "σκεπάσου με το παπλωματάκι σου μην κρυώσεις".
Ομως για κάποιο λόγο και η υπομονετική χελώνα το πιστεύει.
Και αν δεν γίνει στο ΠΣΙΠΣΙΝ θα γίνει στο δάσος η στην παραλια.
Η σε κάποιο υπνοδωμάτιο εφήβου, η έφηβης με την γενικότερη έννοια του όρου, που ονειρεύονται με συμμάχους τ' αστέρια, του ουρανού.
Και να μην συμβεί ιςως ακομα καλύτερα. Η Κανελινα, η υπομονετική χελώνα και οι σοφοί γλάροι μπάνιο θα κανουν και θα χορευουν στην παραλια κατω απο το φως του Ηλιου που δεν αφηνει καμια σκια στην αλήθεια.
When we eat meat...
it may turn out we do not eat the animal but the animal eating us?
In the sense of damage that may de done to our health especially by modern high "tech" meat.
Η Kανελινα κσι το βιβλίο για τη φωνη, Canelina and the book of voice training
See previous euroekectron posts. Σε προηγούμενα euroelectron posts.
Singing for the Stars - Seth Riggs
How to unblock stuck heads on the Tascam porta 1 or 2 without opening it
Your own risk.
By twisting it abruptly clock to anti clockwise or vice versa. Some relevant buttons of the Taos mechanism may need to be pressed or depressed.
It is a while wheel which controls the movement of the heads that has to turn. By using inertia (the property of mass wanting to keep its state of motion) we make it turn but letting it stay stationary and we move everything else.
Once it has rotated a little the motor can take over and move the heads.
Reference:
Conceptual Phydics - Hewitt
The Feynman Lectures on Physics
How resistors work?
It is those fancy colored electronic components.
They convert electric current, (flow of electrons) to voltage or vice versa.
For example the anode load resistor connected to a vacuum electron tube converts the amplified dance of electrons to music to a corresponding varying music signal voltage.
Resistors resist electric current, ie the flow of electrons, because electrons collide with atoms.
The hotter a resistor is the more the thermal movement of molecules. The more there is a chance of collision, the more resistance.
Electrons colliding with the molecules pass on to them energy. So they obtain an increased thermal motion. Thus means the temperature has increased.
References:
Foundations of Wireless or Techique de la radio - Scroggie - Iliffe, éditions radio
Electronics, a systems approach - Neil Storey
Tuning a Piano
One of the most difficult tasks a human being can encounter. It should get easier when one learns.
One should not even think of attempting without knowing first. A thousands of euros damage may result.
A very good book is:
Piano Servicing, Tuning and Rebuilding - Reblitz
Sunday, February 18, 2018
Can plants be programmed to cure us?
(Your own risk)
Is it possible that if...
secretions from the human body are placed inside soil,
the plant that will come up (eg nettles) when eaten
can cure or improve the health of that particular human?
(This is a gross generalization from the fact that plants can take something useless from us, CO2, and create something useful for them (C, they built themselves from Carbon) and O2, oxygen for us to breathe and live from). It is by energy from the sun that the molecule of chlorophyll vibrates more and like a hammer can break CO2, see reference.
Reference:
The Cell - Life Science Library
A glimpse into a vintage German radio studio
One can see an MD21 and much more.
Manuela Monsier Dupont
https://m.youtube.com/watch?v=-PIvno0F88Y
Canelina and Entropy Η Κανελινα και η Εντροπία
Εδω οι σοφοί γλάροι της εξηγούν τη πιο δύσκολη αρχή της φύσης.
Here the wise seagulls explain to Canelina perhaps the most difficult principle of nature.
Πως αυτο που βλέπουμε σε μια κινηματογραφική ταινια ανάποδα μας κανει και γελάμε γιατι ειναι σχεδόν απίθανο να συμβεί. Η εντροπία δείχνει το βέλος του χρόνου.
What we see in a movie going backwards may be funny as it is very very improbable (to happen). Entropy shows the arrow or direction of time
Φανταςτειτε το δικό σας παραμύθι.
Make your own fairytale.
References:
The Distinction of Past and Future - Richard Feynman' s Lecture - YouTube
Conceptual Physics - Hewitt
The Feynman Lectures in Physics
Self serving oat flakes with weighted extras
Do such places exist?
One gets in a plate crushed oat flakes for example.
They they can add:
Whole sesame
Honey
Goji Berry
Raisins
Almonds
Walnuts
Pistachio nuts
Ceylon Cinamom
...
Every self added ingredient is automatically weighed.
At checkout one pays and then adds water for example.
Would this be nice for workplace breaks where one needs an instant, healthy meal without vegetable or palm oil fat which have a reputation of clogging blood arteries?
Η Κανελινα και η άνωση Canelina and Buoyancy
On this episode the wise seagulls explain to her that buoyancy is an electric force. It is same polarity charges repelling. Electrons on her body and electrons of water repelling?
Σ' αυτο το επισοδειο οι σοφοί γλάροι της εξηγούν οτι η άνωση ειναι ηλεκτρικής φύσεως δύναμη. Τα ηλεκτρόνια του νερού απωθούν τα ηλεκτρόνια του σώματος που μπαίνει στο νερό, (ομοςημα φορτία απωθούνται).
In fact no bodies touch. They just come as close as possible until the electron (or protons too?) interaction is strong enough. Canelina wanders if this is why it feels as it feels when the cat with the green ribbon hugs and caresses her.
Στην πραγματικότητα τίποτα δεν αγγίζει τίποτα. Ολα έρχονται τοςο κοντα μέχρις η αλληλεπίδραση αυτη γίνει αρκετα μεγάλη. Η Κανελινα αναρωτιέται αν γι'αυτο αισθάνεται οπως αισθάνεται οταν ο γάτος με την πραςινη κορδελα την χαϊδεύει και την αγκαλιάζει.
She jumps from joy. And they all dance and swim in the water with those billion billion billion electrons under the sun. Our star which sends as many billions of photons per second per square meter to earth and leaves no shadow to truth.
Πετάγεται απο την χαρά της . Και όλοι χορευουν και κολυμπούν με αυτα τα δισεκατομμύρια δισεκατομμύρια δισεκατομμύρια ηλεκτρόνια κατω απο το φως του Ηλιου, του Ηλιου μας που στέλνει τοςα δισεκατομμύρια ηλεκτρόνια στην γη ανα δευτερόλεπτο ανα τετραγωνικό μετρο και δεν αφηνει καμια σκια στην αλήθεια.
References, πηγές:
Conceptual Physics - Hewitt
The Feynman Lectures in Physics
Canelina and fearlessness, Κανελινα και η αφοβία
Α-φοβία. αφοβία. Unphobia. Fearlessness.
On this episode the wise seagulls on the beach explain to canelina that neither fear nor need exist.
Σ'αυτο το επισοδειο οι σοφοί γλάροι στην παραλια εξηγούν στην Κανελινα οτι ούτε φόβος υπάρχει ούτε ανάγκη.
Canelina asks for an example.
Η Κανελινα ζητάει παραδειγμα.
Imagine somebody coming to you with a sword into its case.
Φαντάσου κάποιον-α να ερχεται πανω σου με σπαθί μεςα σε θήκη.
What would you do?
Τι θα κανεις;
If you get scared you grasp it...
Αν φοβηθείς και το πιάσεις...
But it is the case you have grasped and he-she now can very quickly take the sword out thanks to you.
Εχεις πιάσει τη θήκη και τότε χάριν σε σένα μπορεί να τραβήξει το σπαθί αστραπιαία.
Fearlessness does not mean putting ourselves in danger. For example we cross the road carefully. Other example, electronic engineers may have one hand inside the back pocket so as not to touch accidentally a lethal electric potential (voltage) difference on a circuit with both hands.
Αφοβία δεν σημαίνει να βάζουμε τον εαυτό μας σε κίνδυνο. Για παραδειγμα περνάμε τον δρόμο προσεχτικά. Αλλο παραδειγμα. Οι ηλεκτρονικοί μηχανικοί έχουν το ενα χέρι μεςα στην πιςω τσέπη για να μην πιάσουν κατα λάθος υψηλη διαφορα ηλεκτρικού δυναμικού (τάσης) σε κάποιο κύκλωμα με τα δυο χέρια.
References, πηγες:
Description by Lampros.
Περιγραφη του Λάμπρου.
Enchiridion - Epictetous - PDF
Εγχειρίδιο - Επικτητος - απαντα τόμος πέμπτος - Κάκτος
Basic Electronics - U.S. Navy - Dover
Αν η Μαρία Μαγδαλινή ήταν σαν εσενα, ο Χριστός ήταν πολυ τυχερός
If Maria Magdalena was like you, Jesus was very lucky.
Canelina and insecurity, Η Κανελινα και η ανασφάλεια
On this episode the wise seagulls explain to the crying Canelina that the most successful product is insecurity.
Σ'αυτο το επεισόδιο οι σοφοί γλάροι εξηγούν στην Κανελινα οτι το καλυτερο εμπόρευμα ειναι η ασφάλεια.
Reference, πηγές:
Mike's quote, πρόταση του Μιχάλη
Enchiridion - Epictetous, Εγχειριδιο - Επικτητος (απαντα πέμπτος τόμος - Κάκτος)
Saturday, February 17, 2018
Η Κανελινα και η προσαρμογή εμπεδησης Canelina and impedance matching
Σ' αυτο το επισοδειο οι σοφοί γλάροι εξηγούν στην Κανελινα:
Οτι οταν ενα κύμα συναντάει άλλη εμπεδηση, μερος του ανακλάται και επιστρέφει πιςω.
Πχ ενα μπαλάκι τένις που χτυπάει στον τοίχο.
Το μηχανικό κύμα που συνεχεια ανακλάται απο τα ακίνητα άκρα της χορδης μιας κιθάρας. Το κύμα συνεχεια ανεβοκατεβαίνει. Μερος της ενεργειας πηγαίνει στο επίπεδο ξύλο που παλεται που ονομάζεται ηχείο. Ετςι σταδιακά η ταλάντωση σβήνει αλλα η ενέργεια δεν παει χαμένη. Ακούμε την νότα. Η νότα ακουγεται αφου το ξύλο που πάλλεται θέτει σε κινηςη μόρια αέρα. Τελικά καθώς ενα ακουστικό πια κύμα ταξιδευει κάποια μόρια θα συγκρουστούν με το τύμπανο του αυτιού της Κανελινας και θα ακούσει την νότα της κιθάρας).
Το κύμα που ανεβοκατεβαίνει στο σύρμα της κεραίας του πομπού η του ραδιοφώνου. Ανακλάται απο τα άκρα και αφου το κύμα ταξιδευει με την ταχύτητα του φωτός εδώ πια έχουμε πολυ γρήγορες ταλαντώσεις η οπως λέμε μεγάλης συχνότητας. Πχ 92 εκατομυρια φορες το δευτερόλεπτο στον Galaxy 92 FM. Η συχνοτητα εκπομπής του σταθμού ειναι 92MHz. Η μουσική δημιουργεί μικρο διακυμάνσεις σε αυτη τη συχνοτητα. Τα ζηλιαρικα ηλεκτρόνια στην κεραία του ραδιοφώνου της Κανελινας κανουν τον ίδιο χορό με τη μουσική που κανουν αυτα της κεραίας του σταθμού. Ετςι το μουσικο ραδιο σημα φτάνει στο ραδιόφωνο της Κανελινας. Ακούνε και χορεύουν στην παραλια με τους υπόλοιπους κατω απο το φως του Ηλιου που δεν αφηνει καμια σκια στην αλήθεια.
On this episode the wise signals explain to Canelina that when we have impedance mismatch, part of the wave is reflected.
For example a tennis ball hitting a wall. Multiple reflections of the mechanical wave inside a piano string. Multiple reflections of light inside an FM antenna.
Light travels much more quickly so the wave goes back and forth much more quickly. For example at the typical length of a radio antenna, light goes back and forth say 105.3 million times per second or 105.4MHz for London's Magic Radio station. The music creates microvariations to this frequency. Jealous electrons mimic the dance to music of the electrons inside the radio station antenna. So the music signal arrives to Canelina's radio. They sing and dance while swimming under the sun that leaves no shadows to the truth. (A bit more detail on the above Hellenic version).
Πηγές, references:
Musical Acoustics - Donald Hall
Conceptual Physics - Hewiit
The Feynman Lectures in Physics
Feynman lecture at Auckland University - YouTube
https://m.youtube.com/watch?v=xdZMXWmlp9g
Η Κανελινα και ολα τα ήδη φωτός
Σ' αυτο το επισοδειο οι σοφοί γλάροι εξηγούν στην Κανελινα οτι ολα τα παρακατω ειναι φως. Το μονο που αλλάζει ειναι ποσο γρήγορα ανεβοκατεβαίνουν τα ηλεκτρόνια (η συχνοτητα με την οποία ανεβοκατεβαίνουν).
Ξεκινώντας απο χαμηλές προς υψηλές συχνότητες.
Ηχητικό ηλεκτρομαγνητικό κύμα.
(Μην το συγχέουμε με τον ήχο. Εδώ εννοούμε το ηλεκτρομαγνητικό κύμα που θα σταλει και θα ταξιδέψει με την ταχύτητα του φωτός απο μια κεραία μήκους χιλίων χιλιομέτρων αν την συνδέσουμε στην έξοδο ενός μικροφώνου.
Μακρυ ράδιο κύμα (μακρά ράδιο κύματα)
Μεσαίο ράδιο κύμα (πχ η μπάντα των MW η medium wave)
Μικρά κύματα (βραχέα κύματα)
Υπέρ μικρά κύματα (υπέρ βραχέα, πχ η μπάντα των FM)
Μικροκύματα (πχ τα κύματα κινητής τηλεφωνίας η ακομη πιο μικρά μικροκύματα των φούρνων μικροκυμάτων κτλ)
Υπό κόκκινο (υποερυθρο η υπέρυθρο)
Το αισθανόμαστε κοντα σε πηγές θερμότητας
Κόκκινο
Πορτοκαλί
Κίτρινο
Πράσινο
Μπλε
Μωβ (ιωδες)
Υπερμωβ (υπεριωδες)
Μας μαυρίζει το σώμα πχ οταν κανουμε ηλιοθεραπεία
Ακτίνες Χ
Περνούν μεςα απο το σώμα μας
Ακτίνες γ
Κτλ
Πηγη
Richard Feynman lecture to Auckland University - YouTube
https://m.youtube.com/watch?v=xdZMXWmlp9g
Forms of Light
On this episode the wise seagulls on the beach explain to Canelina the cat that:
All the following are light. The only thing that changes is how quickly the electrons vibrate (or their frequency).
Starting from lower frequencies to higher ones
Audio waves
(Not to be confused with acoustic wave sound, an audio, sound or music electromagnetic wave would be emitted at the speed of light if for example an antenna of a thousand kilometers is connected directly to the output of a dynamic microphone)
Radio long waves
Radio medium waves (for example the band MW or medium wave)
Radio short waves
Radio ultra short waves (FM band etc)
Radio microwaves (cellular phones, even shorter microwaves on microwave ovens etc)
Infrared
What we feel when we are near sources of heat
Red
Orange
Yellow
Green
Blue
Violet
Ultraviolet
(It can tan our body)
X-Rays
It can pass through our body
Gamma Rays
Etc
All the above are light but our eye is made to see only a part of the electromagnetic spectrum.
But it's all there. All we have to do is lift the antenna and listen to a soap advertisement.
Reference:
Richard Feynman lecture to Auckland University - YouTube
https://m.youtube.com/watch?v=xdZMXWmlp9g
Radio waves, microwaves, X-Rays etc are light
Reference:
Richard Feynman lecture to Auckland University - YouTube
https://m.youtube.com/watch?v=xdZMXWmlp9g
Friday, February 16, 2018
Any intelligent fool can make things bigger more complex and more violent...
it takes a touch of genius - and a lot of courage - to move in the opposite direction
E.F. Schumacher
The first principle is that you must not fool yourself...
and you are the easiest person to fool
Richard Feynman
The Feynman technique on understanding better
How to study more effectively - YouTube
https://m.youtube.com/watch?v=MlJdMr3O5J4
What a scientist!
Richard Feynman:
One of the great Richard Feynman lectures on YouTube.
Richard Feynman on quantum mechanics:
https://m.youtube.com/watch?v=xdZMXWmlp9g
Η Κανελινα και η Βαρύτητα, Canelina and Gravity
Σ' αυτο το επεισόδιο η Κανελινα κλαίει που δεν καταλαβαίνει ενώ οι συμφοιτητές, συμφοιτητήτριες της στο πανεπιστήμιο κανουν οτι καταλαβαίνουν μπροστά στους καθηγητές.
Οι σοφοί γλάροι της εξηγούν οτι η Βαρύτητα δεν εχει ακομη εξηγηθεί. Ξέρουμε οτι πεφτει ενα μήλο και πως αλλα δεν ξέρουμε το γιατι, πως λειτουργει η βαρύτητα.
Της λένε παραδείγματα για το ασανσέρ που επιταχύνεται και αισθανόμαστε οτι έχουμε μεγαλύτερο βάρος. Δυστυχώς δεν μπορούμε να παρατηρήσουμε πολυ ώρα γιατι το ανσανσερ επιταχύνεται για κλάσματα δευτερολέπτου. Μετα αποκτάει σταθερή ταχύτητα και επιστρέφουμε στο κανονικό μας βάρος.
Της λένε για το αεροπλάνο οταν πευτει για λίγα δευτερόλεπτα σε κενό αέρος και ξαφνικα όλοι ήμαστε παναλαφροι σε συνθήκες έλειψης βαρύτητας.
Ετςι ο Αινσταιν λοιπόν συσχέτισε την βαρύτητα με επιταχυνόμενα συστήματά αναφοράς. Αυτα την δημιουργουν;
Της ειπαν για το φως που καμπυλωνετσι κοντα σε βαρυτικα πεδία πλανητών.
Το φως που χάνεται για παντα; κοντα σε μαύρες τρύπες, συρρικνωμένα άστρα που έχουν τεράστια μάζα αρα και βαρύτητα. Ακομα και το φως που εκπέμπουν γυρνά πιςω σε αυτες, γι'αυτο ειναι μαύρες. Εκει παγώνει ο χρόνος;
On this episode Canelina at a university lecture does not understand and cries.
The wise seagulls in the beach tell her that nobody knows yet why an apple falls. We know it does and how, we do not know why.
They tell her that an elevator, the few milliseconds it accelerates (before the speed becomes constant) makes us feel heavier or lighter. And in fact we are.
They tell her that Einstein thought of this and related gravity to accerating frames of reference. Is acceleration creating gravity?
They tell her that light is deflected when it passes through strong gravitational fields such as near planets. They tell her that black holes are srincked stars with so much gravity that light entering them cannot escape back. And their own light comes back to themselves. So they are black. Does time freeze?
References, πηγές:
General theory of relativity - Einstein
The Feynman Lectures on Physics
Conceptual Physics - Hewitt
Η Κανελινα, οι Τηλεπικοινωνιες και τα Ζηλιαρικα ηλεκτρόνια, Canelina, Telecommunications and the jealous electrons
Σ'αυτο το επεισόδιο η Κανελινα κλαίει που δεν καταλαβαίνει.
Οι σοφοί γλάροι της εξηγούν οτι επιταχυνόμενα ηλεκτρικά φορτία αρα και ηλεκτρόνια που κινούνται παλινδρομικα παράγουν ηλεκτρομαγνητικά κύματα. Ταξιδεύουν με την ταχύτητα του φωτός και θέτουν σε αντίστοιχη παλινδρομική κινηςη αλλα ηλεκτρόνια στο σύμπαν. Για παραδειγμα ο Galaxy 92 MHz στa FM. Τα ηλεκτρόνια στην κεραία του ανεβοκατεβαίνουν 92 εκατομυρια φορες το δευτερόλεπτο. Υπάρχουν μικρο διακυμάνσεις στην συχνοτητα αυτη των 92MHz αναλογα με το σημα της μουσικής. Σαν να χορευουν τα ηλεκτρόνια με την ίδια τη μουσική. Το ηλεκτρομαγνητικό κύμα ταξιδευει. Ζηλιαρικα ηλεκτρόνια μεςα στην κεραία του ραδιοφώνου μας αντιγράφουν την παλινδρομική κινηςη. Ετςι μεταφέρεται η μουσική σε μας μαζι με την μαγεία του ραδιοφώνου. Το FM ραδιόφωνο εφευρέθηκε απο τον ηλεκτρονικό μηχανικό Edwin Armstrong. Η Κανελινα αναρωτιέται...κανουν το ίδιο και τα ηλεκτρόνια στον εγκεφαλο μου;, γι αυτο οταν σκέφτομαι τον γάτο με την πραςινη κορδελα με σκέφτεται και αυτός; Ειναι τα ηλεκτρόνια στον εγκεφαλο μας που αλληλεπιδρούν; Ιςως. Ειναι και η αγάπη ηλεκτρομαγνητικό κύμα;
On this episode Canelina the cat cries as she does not understand.
The wise seagulls tell her that accelerating electric charges, therefore vibrating electrons create an electromagnetic field that travels at the speed of light and makes other electrons in the universe imitate that motion. For example at the antenna of London Magic FM Radio station electrons go up and down at a rate, frequency of 105.4MHz or 105.4 million times per second. This is the carrier frequency. There are micro variations to this frequency by the music signal itself. As if electrons
dance to the music. When the electromagnetic wave arrives to us, the jealous electrons inside our radio antenna mimic as closely as possible the motion. So the music arrives to us. FM radio was invented by electronic engineer Edwin Armstrong. Canelina wonders if this is the same reason that when she thinks of the cat with the green ribbon, he is thinking of her too. Is it the jealous electrons in our brains? Maybe. Is love an electromagnetic wave?
References, Πηγές:
Richard Feynman on Quantum Mechanics - University of Auckland 1979 - YouTube
https://m.youtube.com/watch?v=xdZMXWmlp9g
The Feynman Lectures on Physics
Conceptual Physics - Hewitt
How does a mirror work, Πως λειτουργει ο καθρέπτης - euroelectron blogspot
A simple rule to protect vocal chords, Ενας απλός κανόνας για προστασία φωνητικών χορδών
Using common sense.
Stoping immediately at the slightest sense of strain.
Drinking water a while before singing helps lubricate the vocal chords.
Χρησιμοποιούμε κοινή λογική.
Σταματάμε αμέσως μόλις αισθανθούμε την παραμικρή ενόχληση.
Αν πιούμε vερό λίγη ώρα πριν τραγουδήσουμε λειτουργει σαν λιπαντικό για τις φωνητικές χορδές.
Reference, πηγη:
Singing for the Stars - Seth Riggs
Thursday, February 15, 2018
Η Κανελινα και η επιλογή μικροφώνου, Canelina and the choice of microphone
Σ'αυτο το επεισόδιο η Κανελια κλαίει που θυμάται το προηγούμενο καλοκαιρι την Λούσι να τους λέει με τι μικροφωνο γράφτηκε καθε τραγουδι. Αποφασίζει να προετοιμαστεί για το επόμενο καλοκαιρι που θα έρθει η Λούσι. Ετςι πηγαίνει στους σοφούς γλάρους. Της εξηγούν οτι τα μικρόφωνα μετατρέπουν παλινδρομική κινηςη μορίων σε παλινδρομική κίνηση ηλεκτρονίων μεςα σε σύρμα καλωδίου, μεςα σε σωλήνες κενού ηλεκρονιων κτλ. Της εξηγούν τα βασικά είδη μικροφώνων με παραδείγματα τραγουδιών. Κορδέλας (ταινιας) σε μαγνητικό πεδίο η ribbon στο Back to Black - Amy Winehouse. Κινητού πηνιου στα τραγούδια των U2, Sade η Fleetwood Mac. Ηλεκτροστατικο η πυκνωτικο στα τραγούδια των Beatles. Της εξηγούν έναν άλλο τροπο διάκρισης, παντοκατευθυντικο η πίεσης (omnidirectional or pressure) η κατευθυντικο η πρώτης παραγωγου της πίεσης ως προς απόσταση (directional or pressure gradient). Της εξηγούν οτι για ενα φαινόμενο ανάλογο της παληριας στα κατευθυντικα οι μπαςες συχνότητες αυξάνουν οςο τα πλησιάζουμε. Της δίνουν παραδειγμα παντοκατευθυντικου τα τραγούδια των Carpenters με την Caren Carpenter να τραγουδάει με το Neumann U87 σε omni mode που συμβολίζεται(O) κοντα στο γυαλί του control room. Υπάρχουν και τα κρυσταλλικα η πιεζοηλεκτρικα μικρόφωνα . Ακούγονται ομορφα με μικροφωνικές με σωλήνες ηλεκτρονίων, για παραδειγμα την FBT 1002 personal.
On this episode the wise seagulls explain to Canelina the cat that microphones convert the vibration of air molecules to vibration of electrons inside wire, vacuum electron tubes etc. They explain her the usual microphone types with song examples. Ribbon in magnetic field, Back to Black- Amy Winehouse, Kiss Me - Sixpence none the richer. Moving coil in magnetic field, U2, Sade, Fleetwood Mac. Electrostatic or condencer, eg Beatles. They also explain how some mics belong to the set of omnidirectional and some to the set of directional microphones. They explain to her that due to a phenomenon similar to sea tides, directional mics emphase low frequencies the closer we sing to them. They give as an example the songs of Carpenters recorded with a Neumann U87 stuck in omni mode and Karen Capenter singing near the control room glass. There are also piezoelectric microphones. They sound beautifully with electron tube PA systems such as FBT 1002 personal.
References:
Microphones - John Borwick
Microphones - Burroughs (Electro-Voice)
The microphone bible - Electro-Voice
Sennheiser micro revue
Neumann microphones PDF - Boré, Peus - Neumann
Amy Winehouse recording Back to Black - YouTube
Tips for recording musicians - John Harris
Recording the Beatles
https://www.gearslutz.com/board/so-much-gear-so-little-time/518947-anyone-use-omni-mics-vocals.html
The Feynman Lectures on Physics
Conceptual Physics - Hewitt
Canelina and the Bach Code, Η Κανελινα και ο Κώδικας Μπαχ
Σ'αυτο το επεισόδιο η Κανελινα κλαίει που δεν μπορεί να ακούσει και να συσχετίσει τις συγχορδίες της συμφωνικής η ποπ μουσικής. Οι σοφοί γλάροι της λένε να κατεβάσει το εγχειρίδιο του Μπαχ για τους μαθητές του. Εκει σε λίγες σελίδες εξηγούνται τα παντα για την καλη μουσική καθε είδους αφου και οι πιο εκλεπτυςμενες συγχορδίες ειναι οι ίδιες. Τα όργανα αλλάζουν. Και οι μουςικες νοτες ειναι μονο 7. Η Κανελινα σκέφτεται οτι το εγχειρίδιο ειναι τοςο σημαντικο που θα μπορουςε να βγάλει ακομα και μια χώρα απο την κρίση. Την πειράζει η υπομονετική χελώνα που και αυτη το πιστεύει.
On this episode Canelina the cat cries as she cannot correlate the beatiful chords of symphonic or pop music which are the same anyway as the musical notes are just 7. Only instruments change. The wise seagulls on the beach encourage her to download the Bach Bass Rules code of J.S. Bach to his students adapted from the Niedt manual that was given to Bach when he was young.
References:
Bach Bass Rules PDF
Same as Instructions for playing four part harmony and figured bass by her Johann Senastian Bach to his scholars in music - Bach's biography - Spitta - (appendix)
Canelina and the book for singing voice training, H Κανελινα και το βιβλίο εκπαίδευσης φωνής, τραγουδιού
Σ'αυτο το επεισόδιο η Κανελινα κλαίει, κλαίει που δεν τραγουδάει σαν την Αγγλίδα γάτα. Οι σοφοί γλάροι της συστήνουν να πίνει νερό μισή ώρα πριν τραγουδισει για λιπαντικό των φωνητικών χορδών. Τον χρυσό κανόνα, να σταματάμε αμέσως μόλις αισθανθούμε οποιαδήποτε ενόχληση στο λάρυγγα. Και το βιβλίο του δασκάλου της Madonna, Barbara Steisand κτλ με τίτλο Singing for the Stars - Seth Riggs
On this episode the wise seagulls on the beach recommend Canelina to drink water half an hour before singing as it is a lubricant for the vocal chords. They remind her the protective rule of immediately stopping singing whenever she feels any stress on her larynx. And they recommend her to buy from eBay, Amazon etc the book of the teacher of Madonna, Streisand etc Singing for the Stars - Seth Riggs. Canelina jumps from joy and they all dance and swim to the sea under the morning sun which leaves no shadows.
Reference:
Singing for the Stars- Seth Riggs
Η Κανελινα και η αγγλική προφορά Canelina the cat and correct English pronunciation
Σ'αυτο το επεισόδιο η Κανενινα κλαίει που δεν εχει προφορά σαν την Αγγλίδα γάτα. Παει στους σοφούς γλάρους και της λένε για τα phonetics (γράμματα με κώδικα προφοράς) που εχει καθε καλο λεξικό μετα καθε λέξη και κλειδί στα περιεχόμενα. Της λένε επισεις για το μαγικο βιβλίο προφοράς που λέγεται Ship or Sheep (σιπ οο(ρ) σιιπ).
On this episode the wise seagulls recommend Canelina to learn the phonetic code which good dictionaries have after every word, the key of the code on the appendices and the fantastic book with audio examples called Ship or Sheep, (Sip o: Si:p).
References:
Ship or Sheep - Baker - Cambridge
Oxford, Longman, Cabridge,...,Dictionary of English
Wednesday, February 14, 2018
What is the series heater resistor on the Pleiades V6 for further underheating the cathode
Aproximately 9 Ω.
Battery supply is 3.9V.
So the heater gets only about 2.5V!
Anode current is 30μA at these conditions.
Current through the heaters is aproximately 150mA.
The EF183 electron tube still operates satisfactorily at those conditions. The sound is great and unstressed, easy, natural.
The anode to grid accelerating resistor used is 8MΩ.
Reference:
Pleiades V6 schematic
Pleiades V6 with Magnetec core input transformer connected to Sennheiser MD441, Paso 980, Electro-Voice 635A, AKG D130
The primary inductance of the input transformer used is only 140mH. Secondary inductance is 16H. It is the version 1 transformer who did not make it as an output transformer. Turn ratio 1:10.
The sound was great but a little bass light in 635A due to the low input inductance for this microohone. The mic was used at a distance of 1in. Otherwise room ambience, reverberation gets in. With D130 the sound was slightly hard.
The MD441 U3 operated greatly at a distance of a few inches. The proximity effect was compensated in an impressive way. The brilliance switch is ingenious indeed. It is a joy to hear the smooth sound and flat frequency responce curve with no increase at mid highs.
There was some electromagnetic field noise captured by the mic which disappeared when the mic was rotated. The test inviroment is very electromagnetically noisy from other parts of the building. It has to be investigated what the cause is.
The Pleiades V6 was tested in breadboard condition. The Magnetec core transformers are unshielded. There did not seem to be a problem with the Electro-Voice 635A.
The Paso M980 sounded great too. Proximity compensation is important.
References:
Pleiades V6 schematic
Photo electron tube mic prepreamp
Electrons can be emitted by light, photons striking the cathode.
The few megohms electron accelerating resistor from anode to grid makes operation possible with just a few volts at the anode. The electron tube operates successfully with a low (in micro amps) current at very low noise.
Is this suitable for space supplications?
Notes
Same as Pleiades V6 preamolifier.
But electrons are emitted by light striking on cathode.
Same idea anode to grid few Megohm resistor as electron accelerator.
Would this be useful in satellites, radio telescope, space communication?
Reference:
Pleiades V6 schematic
Neumann U47 schematic
On preserving transconductance - Euroelectron blogspot
The secrets of Neumann U47 part 2
This is rewriting the old post possibly with some additions
1. Heater voltage reduced. The heater voltage used is less than the specs of the VF14 tube. See next post in advantages of reduced heater voltage or cathode temperature.
2. Cathode connected to a very snall resistor, It is possible For it to be small as Georg Neumann passed the heater current thought it too. V=IxR (Comment by studio technician Boby).
3. Rectification effect at large signals. The tube gain is reduced. The release constant of the variable gain or compressing action is dictated by the discharge of the grid through the grid leak resistor?
Reference:
Neumann U47 schematic
Altec or RCA BA6A compressor schematic
Advantages of Reducing the Heater Voltage, making an electron vacuum tube preamplifier much more listenable
Examples:
Neumann U47 microphone. Heater about 20 Volts less?
AKG C12A microphone. Heater 5V instead of 6.3V.
Pleiades V6 prepreamplifier. Heater 3V instead of 6.3?
Even power amplifiers may benefit.
For example
Pleiades Electra 2, headphones amplifier with one 12K5 tube per channel and nothing else.
Heater is 8.9V? instead of 12.6V.
While developing it, it was amazing how better underheating sounded. This came up by chance as the 12V lead acid battery was discharging as music was listened to for more than an hour.
In general it seems underheating the cathode makes the sound much more easy to listen to. Natural. Unstressed.
Although it is possibly not known yet why, here are some thoughts.
1. As the output impedance of the tube increases the surrounding reactive components introduce gentle roll offs at the frequency extremes. The first mathematical derivative or slope of the curve equals to time delay. An abrupt slope has abrupt change of time delay with respect to frequency. So a gentle slope should preserve better the waveform especially the transients.
2. Gentle roll offs also compensate for Fletcher-Munson, voice effort effects.
3. Electron tube running at low temperature. Reduced secondary emission of electrons from high temperature, from photo emission etc. (The cathode glows less). Less noise.
4. Perhaps better overload characteristics as saturation takes place by having no more electrons to do the job. Like on magnetic tape saturation. Gradually running out of steam of electrons. More instantaneous peak limiting, more tube sound or natural sound.
(How would an electric guitar preamp or amp sound with tubes underheated?)
5. If there is increase of tube input impedance this changes the release time of U47 compressing from the diode rectification effect at large signals.
6. Lower power consumption. Especially important to battery low voltage operation,
Less heat generated by the tube. Important when the tube is inside an enclosed space such as U47, Pleiades V6 etc. On the V6 preamplifier it is important as the battery is inside too.
7. More tube life. VF14 tubes used on U47 still operate. If not? a way to revive or repair the VF14 (your own risk) is to reactivate the cathode by connecting it carefully (with ell safety precautions) to the rated heater voltage for a while. Perhaps excededing a bit. This has been tried successfully to get back to normal a noisy VF14. See relevant euroelectron post.
8. Less electron cloud biases less negative the grid. (The cathode is less positive). This can be observed by just connecting even only heater voltage and measuring the potential from grid to cathode with any voltmeter, no special voltmeter is needed. Even one with not so high input impedance will show the effect. For some reason it seems underheating brings more information extraction from the source.
Less hiss.
Apart from the great sound quality, one way to distinguish if an amplifier is operating using the underheating principle, is the slow turn on time, this can be observed on U47, C12A, Pleiades V6 etc.
If there is more information extraction, less noise... How would an RF front end amplifier operate? Possible uses, radio telescope, (seeing the past of the universe). Has this great U47 cathode underheating principle been applied to space communication or radio telescopes?
8. More gain. On V6 the gain increases if the heater voltage is further reduced from 3.9V to nearly 2.5V! (This again with an 8Megohm electron accelerating resistor from anode to grid and 4.9V anode supply.
Is the Pleiades V6 front end amplifier suitable for space as it is battery powered so ready to operate with small solar cells as it only consumes 3V at 150mA.
Electron tubes are very suitable for space as they are not influenced or destroyed by ionizing radiation.
Other vacuum electron tubes that have been found to operate great with low anode voltage and possibly underheating are. ECC82, 7025 tested successfully with low anode voltage and underheating. EF86, EF37A, 6SK7, 12SK7, all triode connected tested successfully with low anode voltage but not tested with underheating yet. Low voltage operation is possible with the Anode to Grid few Megohm resistor. It serves to cancel the internal negative bias of the grid or positive cathode due to electrons emitted to the space charge cloud. The bias is still negative after connecting the resistor but much less so making the operation of tubes in anode voltages as low as 3V.
More investigation is needed.
References:
Neumann U47 schematic
Pleiades V6 schematic
On preserving transconductance (at low anode potential) - euroelectron blogspot
Operating features of the Audion - E.H. Armstrong
The use of Multigrid tubes as electrometers, J.R. Prescott, Melbourn University
How to operate almost any valve, electron tube or vacuum tube with low battery voltage
On the next euroelectron post with title Hacking electron tubes.
Hacking an electron vacuum tube to operate at low battery anode voltage
How it is done:
At your own risk, all safety precautions should be taken anyway.
1. If it is not a triode, connecting all grids except the control grid directly to anode, (triode connection).
2. Connecting the cathode directly to ground or battery -.
3. Connecting one (a few Megohm) resistor from anode (plate) to control grid.
4. Underheating the heaters.
5. Coupling the signal to be low noise amplified to the control grid through a capacitor so as not to upset the DC conditions. For example a microphone input transformer's secondary is connected through a capacitor to the control grid.
6. Using an output transformer directly to anode will make operation possible at even less supply voltage or Vb.
For example the Pleiades V6 microphone pre preamplifier operates with 3.9 volts on both anode and heater circuit. It uses an EF183 high gm, variable gm electron vacuum tube triode connected.
Another way is connecting the input transformer secondary to grid. A low variable cathode resistor, Rk, in order to find the sweet spot, max gain spot exoerimentaly. For example the Pleiades V-1 with the 7025 electron vacuum tube. Heater supply is 5V, anode supply is 18V.
References:
On preserving electron tube transconuctance (at low anode voltage or potential) - euroelectron blogspot
Pleiades V6 schematic
2 Sennheiser MD214 should make a great 3D binaural microphone
Assuming the microphones are modified with respect in such a way that there is easy undo and no damage.
If the internal electrical filters are bypassed...
Then placing each mic next to each ear should produce state of the art 3D recordings for headphones playback.
The moving coil capsules should be excellent as in the Sennheiser micro revue catalog is mentioned that they are the same to MD211. And they are mechanically isolated from the mic body.
References:
Sound and Hearing - Stevens., Warshofsky, Time Life
Sennheiser micro revue 70-71
Why do listeners brain seem to prefer audio transformers in the signal path
Tracing the origin of successful and great sounding recordings of all time one can find more than one signal transformer in the signal path from record producer's brain to listener's brain. An obvious example is for example the transformer inside a Neumann U47. The input, output transformer of the following preamplifier,..., the output transformer of the class A 300B power amplifier of the listener.
Some reasons why.
1. Restricted bandwidth helps make the sound correct to the listener's brain. If gentle roll offs do not exist then the sound is bass heavy and treble heavy to brain perception due to voice effort curves, Fletcher-Munson equal loudness curves, proximity effect for low frequencies, pressure doubling effect for high frequencies, low frequency reasonant modes of 99.9% of environments not treated with low frequency absorbing membranes for example.
2. Possible peak limiting saturation characteristics due to B-H curves. This may result in an increased average value of signal. And also a subjective increase of loudness due to lifelike overtones produced. In fact an audio transformer is close to a simulation of an analog tape recorder instanteniously reproducing.
3. Canceling of RF and other noises, from balanced operation. If in phase moving electrons enter both input terminals they electrically collide so those fields are extinguished. In fact it is the electromagnetic fields that collide, one field entering one terminal, a similar filed entering the other terminal.
4. Damping of the electron carrying (moving to sound) element in moving coil or ribbon microphones. By Lenz's law or conservation of energy. The same way electromagnetic brakes operate on metro trains or other electrical vehicles. So reduced pops.
5. Stepping up the signal voltage reduces hiss produced by the following active preamp stage.
6. They do impedance matching. Therefore no reflection of signal energy back or less reflected back. Impedance matching is one of the most important principles used by human civilization. An obvious example is how the Pyramids, or Parthenon in Acropolis were built, by using mechanical passive impedance matching amplifiers.
7. Stepping up the voltage and therefore impedance makes a moving coil's signal high and high Z like a condenser capsule. Then an electron tube or JFET is used as an active device to further increase voltage and increase current so it can drive long cables just like condenser internal prepreampifiers.
Disadvantages:
What are the disadvantages of transformers?!
They may not be easily mass produced?
Why should one eat a mass produced cake, bread, snack which has in the tiny letter ingredlists list of the packaging, (cheap) vegetable oil, palm oil or palm fat which have a reputation of clogging blood arteries? That makes the mass produced snack cost less than a euro and thousands of euros to be spent for the long run health damage.
In the well known fairytale series, Canelina the Cat needs her friend the Patient Tortoise to hand wind the transformers and inductors.
References:
The Feynman Lectures in Physics - Feynman, Leigton, Sands
Flat frequency responce not from mic to loudspeaker but from singer's vocal chords to listener's brain, Sound Picture Recording and Reproducing Characteristics - Loye, Morgan - Journal of the Motion Pictures Sound Engineers
Sound and Hearing - Stevens, Warshofsky - Time Life
Tubes vs Transistors, is there an audible difference? - Russel O. Hamm - Journal of the Audio Engineering Society
Fringe Knowledge for Beginers - Montalk
Enchiridion - Epictetous
Tuesday, February 13, 2018
The Pleiades V6 connected to AKG D130 or Electro-Voice 635A
The Pleiades V6 is an one electron tube battery powered pre preamplifier or booster pre preamp designed to extract as much information as possible from a microphone while sounding correct to the listener's brain.
It is based on the legendary Neumann U47 amplifier and attempts to improve if that could be possible on the simplicity, purity and excellence of this deliberately underheated state of the art VF14 electron tube circuit.
The Pleiades V6 is to be connected to moving coil or ribbon microphones through its input transformer, but connection to any other type of microphone may be possible too.
Referring to the Pleiades V6 schematic.
This test was carried out on the Pleiades experimental jig. The jig is as follows. Three small breadboards are connected one after the other from left to right. One for the input transformer with octal base. One for the EF183 electron tube. One for the octal base output transformer.
The input transformer for this test is the green Altec Peerless 4722. Step up ratio is 1:30. Primary inductance is aproximately 400mH.
The electron tube is powered by 3 1.2V rechargeable AA batteries. So normally the heater voltage and anode voltage are about 3.9V. The electron accelerating resistor used from anode to grid Rag is 8ΜΩ. The tube is quietly powered on by connecting the lead to heater supply as the anode circuit is always connected to the battery. An available option is to pass the heater current through a wirewound rheostat resistor thereby further reducing the temperature of the cathode from the already relative small temperature from the 3.9V instead of 6.3V. When the tube cathode is heated by 3.9V the anode current is 100μA. When the rheostat was connected the heater voltage was such that the anode current dropped to 40μA. The tube still operated in a great way and perhaps more natural sounding with still easier sound. It seems electron tubes or electrons like anyone do not like to be forced to potentials etc. See later comments.
The output transformer connected is the version 2 Pleiades output trasformer. It is wound on Magnetec 070 nanocrystalinne ring core. 672 turns for the primary giving an inductance of 80 Henries or 80H and 70 turns for the secondary (output of prepreamp) giving an inductance of 800mH.
Signal path, setup:
male voice - mic at 1-12in - Pleiades V6 - 10KΩ impedance mic input of Realistic Disco mixer, (mono button pressed) - Sennheiser HD580 precision headphones
It was a bit strange that when gently tapping the mic there was a click sound on the headphones even before applying heater voltage. The electron tubes seems to operate from the anode voltage supplied. Is this operation happening by capacitance or a few electrons available, or by photo emission?)
Firstly the AKG D130 was connected. It took time for sound to come. Perhaps more than 40 seconds.
There was sound even before the 40μA point. As the 40μA anode current was reached the sound was already full and a lot of detail could be heard from sound sources outside of the building, dozens of meters away.
Reducing the fader and singing to the mic the sound was very full. Perhaps a bit bass heavy with great mid and treble detail. When the heater voltage was increased to 3.9V, the anode current went up to 100μA and the bassiness increased as expected from the output transformer being driven by a lower electron tube output impedance.
It was then decided to change to the Electro-Voice 635A which sounds less bassy than the D130.
It was fantastic too. Better in frequency balance to listener's brain. At 100μA the sound was full, slightly bass heavy.
At 40μA the sound was amazing. Everything sounding with a natural spectral balance to listener's brain. The sound was easy. With scary treble detail without any harshness. As if there was no microphone or amplifier or headphones. As if the sound was guided by a perfect frequency responce acoustic tube from mouth to ears.
When a terminating load of 800Ω was connected to V6's output the sound was more hi-fi with the wrong sense of the word. There was more treble and bass extension as expected and the result was worse as expected to listener's brain. The gentler roll offs when the amplifier is terminated with 10KΩ seem to compensate voice effort and Fletcher-Munson curves making for a pleasing natural result to brain perception.
When the mic was disconnected from the female XLR it was a joy to hear how quiet with so little hiss and no noise like hum the battery powered Pleiades V6 pre preamplifier is.
Once the mic is connected it is sticking how immediately all ambient noise from outside the building can be heard through the double glassing windows.
References:
Pleiades V6 schematic
Neumann U47 schematic
On preserving transconductance of electron tubes (with an anode voltage as low as 3 volts) - euroelectron blogspot
(Flat frequency responce from singer's, actor's vocal chords to listener's brain) Sound Pictures recording and reproducing Characteristics - Loye, Morgan - Journal of the Motion Pictures sound engineers
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