Playing with cathode temperature on electron tubes

It reminds a bit experimenting with temperature for baking croissants, the pastry made with real milk butter, (instead of the usual vegetable butter or palm oil which has a reputation of clogging arteries).


It is great fun playing with cathode temperature by adjusting the heater voltage when the tubes operate at low anode potentials as on the Pleiades amplifiers. The easiest before doing this is just disconnecting the heater circuit and listen to what happens. On low level pre preamplifiers such as the Pleiades V series the sound output increases and noose decreases. A similar principle must be used on the Neumann U47 electron tube condenser microphone which has the VF14 heated at a much lower than specified by the manufacture voltage.


The change of grid potential with respect to cathode can be monitored with a voltmeter and the music output of the amplifier can be listened to in real time.


The cathode is usually connected to ground on most Pleiades amplifiers so the voltmeter black lead is just connected to chassis or battery minus.


It is also very interesting to carefully connect (always use fuse) just a heater voltage on any tube and observe the grid becoming progressively negative wrt cathode as the cathode heats up. And this without connecting anything else to any other terminal. This shows that nature internaly biases the grid negative or the cathode positive as electrons escape from the heated cathode.


This possibly explains why a tube is cut off at low anode voltage.


On Pleiades amplifiers a tube operates normally at very low anode potential by compensating this internal negative bias effect externally with a high Megohm resistor from anode to grid.


The grid bias may still be negative but less so and the electron tube operates in an unheard off low noise and sound quality.


References:


Operating features of the Audion - Edwin H. Armstrong


On preserving transconductance of an electron tube at anode potentials as low as 3.6V - euroelectron blogspot


Fringe Knowledge for Beginners - Montalk - free PDF

Effect of changing the cathode temperature on the grid potential

While exoerimenting in practice on the Pleiades Elektra III with resistors from anode to grid ranging from 1.8MΩ to 470KΩ, there is not much difference in sound. Even with 470KΩ from anode to grid the grid potential assumes the value of -200mV from the value of -400mV when Rag is 1.8MΩ. Of course when the cathode is left to cool down the grid potential grows up to that of the battery ie 12V.


Even more strange is that the sound is not much different varying the grid potential from -400mV to 400mV.


The easiest and most effective way to vary the grid potential is by changing the cathode temperature. The easiest way to do this in real time is to disconnect the heater circuit and monitor the grid potential with respect to cathode and listening to music at the same time.


Or connecting a variable power wire wound potentiometer in series with the heaters.


Setup, signal path:


Portable Sony CD player with line out - Pleiades Ekektra III - Sennheiser HD580


There is something very nice about the Pleiades Elektra III.


Is it the sweetest sounding amplifier on the planet?


Each Channel is using only 1 resistor, 1 capacitor, 1 electron tube, 1 coil (the voice coil of the headphones themselves)


Increasing the anode voltage to 18V from 12V did not necessarily produce a better sound.


Decreasing the Rag did not nessasarily produce a better sound.


The above 2 variations could be combined.


For the time being the amplifier will be as chance let with 12V power supply and 1.6MΩ from anode to grid to free the electrons.

Variable bias on Pleiades amplifiers adjusting threshold of peak limiting

For example.


On Pleiades Elektra III headphone electron tube battery powered amplifier.


The Rag resistor from anode to grid can be a 2MΩ potentiometer in series with 470KΩ. The Rag resistor makes possible the freeing of electrons to make the EF183 triode connected electron tube operate at 12V or less anode voltage.


So that bias can be adjusted for any listening volume. This can provide instatenious peak limiting making the signal more suitable to listener's ears or perception  and ordinary listening conditions.


Hearing protection is provided too by the limiting action.


The variable bias voltage may effectively adjust the threshold of limiting or in other words the power output of the amplifier for a given amount of distortion.


At small signals and near the average level where most of the music exists, the amplifier is extremely linear since it is biased in class A operation. The nearest the excursions of the signal from the operating point the more linear the electron tube is.


The user adjusts for best possible sound according to the listening conditions.


Having said the above:


While exoerimenting in practice on the Pleiades Elektra III with resistors from anode to grid ranging from 1.8MΩ to 470KΩ, there is not much difference in sound. Even with 470KΩ from anode to grid the grid potential assumes the value of -200mV from the value of -400mV when Rag is 1.8MΩ. Of course when the cathode is left to cool down the grid potential becomes that of the battery ie 12V.


Even more strange is that the sound is not much different varying the grid potential from -400mV to 400mV.


The easiest and most effective way to vary the grid potential is by changing the cathode temperature. The easiest way to do this in real time is to disconnect the heater circuit and monitor the grid potential with respect to cathode and listening to music at the same time.


More difference in power output was observed while driving a full range speaker with one EF183 through an output transformer.


More details on nearby euroelectron posts.

Do not react

Do not react is said by Hiliana.


Reacting may lead to a trap.


Further reacting to a worse trap.


Further reacting to an even worse trap.


This can take someone futher from his, her route and cause delay until one is back on track.


Reacting  can always be stopped.


If something that seems bad happens, it can ignored.


At the end it may not prove as bad as it was thought it was.


And ignoring it did not delay us from our chosen course of life.

The Pleiades Electra III electron tube battery amplifier sees today the light of day

EF183 valves directly coupled to 300Ω headphones.


It is a transformerless stereo electron tube headphone power amplifier using 2 EF183 electron tubes operating in class A with just 12V for heaters and anodes. Class A operation means electrons are flowing all the time.


The headphones themselves play the role of the anode resistor. The 300Ω voice coils of the Sennheiser HD580 for example are directly connected to the anode. A small DC current passes through the headphones. So the class A principle is extended to the voice coils too, electrons flowing all the time.


The operation at only 12V anode voltage is made possible by a 1.6MΩ resistor from anode to grid, for freeing the electrons. Without it the electron tube would be biased negatively 2 times, one inside the tube by nature and one by the external components. Acknowledgement to Hliana Stalika for insisting that the electron tube should not be negatively biased.


Since this technique makes possible an anode current of the order of milliamperes at 12V anode potential (high current at low voltage), this means by R=V/I that the electron tube output impedance is reduced making possible the impedance match of various loads without the need of an output transformer.


The components used:


(See also part 2 including output transformer)


2 EF183 electron tubes triode connected (anode connected to screen grid and suppressor grid). One EF183 per channel.


2 1.6ΜΩ resistors from each anode to control grid for freeing the electrons.


2 1μF coupling capacitors connected to grid for not upsetting it DC wise by the music signal source.


1 stereo 47kΩ log RFT potentiometer.


1 12V battery.


Signal path, setup;


Various CDs including Ray Conniff - SONY portable CD player with line out - Pleiades Elektra III with 12V small lead acid battery - Sennheiser HD580 headphones


The sound is unbelievable.


Extending bass and treble, giving the impression of a frequency responce from 0Hz to MHz. It sounds more extended to Pleiades Elektra II. Why?


Amazing mid range.


Every instrument sounds real. And each instrument can be distinguished. It is much easier to find out what note each instrument is playing.


Transparent.


Immediately reveals the weak and strong points of a recording.


It sounds so musical one does not want to stop listening.


More technical information:


The heaters are in series and connected to 12V.


The cathodes are connected to ground or battery negative.


The headphones are connected directly to the anodes. The other side of the voice coils, ie the headphones common ground terminal is connected to +12V positive. Plastic ungrounded headphone connectors should be used.


The anodes are always connected to the battery when the headphones are plugged in. Then the heaters are powered and this is the smoothest possible turn on and off. Headphones should not be connected or disconnected while the amplifier is no. The clicking sound may damage hearing. And in general we never increase volume when listening with headphones therefore keeping intensity low.


The noise performance is amazing as the EF183 connected in a similar way can be used as a front end pre preamplifier for the faintest possible microphone, moving coil cartridge or even radio telescope signal. See Pleiades V series preamplifiers. No noise will be heard even if the output of this amplifier is connected to another amplifier.


Using 1.6MΩ from anode to grid makes the grid have a bias of -350mV.


The voltage across each headphone voice coil is 600mV.


A disadvantage is that when connecting the HD580 headphones for example, the frequency responce has a broad rise of 4-5dB peak at around 70Hz, and +1 dB close to 16-20KHz. This indicates the output impedance is higher than 300Ω, (3-5 KΩ?) and the change of the headphone impedance with frequency affects the voltage output of the amplifier. Subjectively it sounds a bit like room coloration, most rooms have an increase in then low mid range due to standing waves. It is not the same though as a room reverberates. This is at Ia=2mA, (600mV across the headphones voice coil). If the anode current is increased there should be improvement as the output impedance of the amplifier will be lower. The coupling capacitors of 1μF may be a cause and they can be reduced. Also experimentation can be made with an output transformer to reduce the impedance of the amplifier to 300Ω. And a tap can be made for low impedance headphones too.


Another way to reduce the output impedance without an output transformer is to connect 2 resistors in series as an anode load and take the signal from the low resistor. In this case if we take all precautions including protecting our ears while connecting, the headphones can be directly connected to the low resistor. Vb may need to be increased. If we do not want to use resistors many headphones can be connected in series so that the total load is comparable to the electron tune output impedance. This may serve many listeners.


Would a 6SN7 electron tube with a electron freeing resistor from anode to grid have a lower output impedance. It seems difficult to increase the anode current of the EF183 to more than 3mA at 12V. Much earlier experiments showed the 6SN7 aand 12SN7 electron tubes, triode connected to be quite promising. Currents can't be readily recalled but it is rememberedfor an anode old and take the that those tubes were giving kicks to the curre nt reading needle when the grid was connected through high resistors to anode for example.

. If we do not want to,use resistors
The amplifier starts gently overloading and sounding fuller at not a very loud intensity protecting the ears.


(Playing sine waves clearly shows that when the amplifier starts overloading 2nd harmonic distortion is produced which sounds nice. On the oscilloscope the waveform is unsymmetrical, the top becoming round and the bottom of the waveform thinner, confirming 2nd Harminic production. The amplifier stops showing an increas in VU at -10dBm. When playing music the amplifier sounds very nice at -20dbm average, leaving headroom for peaks, and being kind for ears as this is not a high intensity. The measurement was made by connecting a VTVM across the 300Ω heAdphone voice coil on one Channel.


Another strange thing about this amplifier is that although it sounds terrific, like a tape recorder running at 10x 30ips, the waveform of a sinewave at the scope looks completely unclear. It is still a sinewave but the line is 20x thicker. This indicates radio frequency oscillation. The line stops being thick when the CD player is stopped. It also happened connecting to the CD player's headphone out. It still happens if the anode to grid resistor is disconnected from the anode and connected to Vb. The amplifier sounds terrific as if a real orchestra is performing with the most high frequency yet smooth and untiring to the ear overtones. Could it be that a very high frequency exists and performs a similar function to the ultra sonic bias frequency that tape recorders use?


Another area that has to be looked at is why almost exactly the same configuration but with an output transformer connected to the anode and a full range loudspeaker, produced an anode current of the the order of 6mA when Rga was less than 1MΩ and Vb up to 18V. This is described on a previous euroelectron post.The EF183 used was a Philips instead of Telefunken, both NOS. Preliminary experiments to increase the anode current above 2mA where not as successful. And swapping tubes did not produce any immediate anode current change. The loudspeaker driving version may have to be re examined).


The sound seems 10 times as big.


It is smooth.


Reducing the 1.6mΩ carefully should increase power. 1.6mΩ was chosen by chance, see yesterday's experiments with 1MΩ.


When the heaters are disconnected the amplifier keeps playing for a long time, many seconds, indicating that the cathodes may be overheated for this application. Underheating may be tried.


Wishing everybody listening to the Pleiades Elektra III be as happy as I am.


References:


Operating features of the Audion - Edwin Armstrong


On preserving the transconductance of electron tubes at anode potential as low as 3V - euroelectron blogspot

One must never change his or her course of life for anyone ore anything

Said by Lampros.

Does the human octave perception and the dependence of pitch on intensity have a common explanation?

Long time ago on a demonstration by the piano tuner Albert Ketentzian a 440Hz tone was played on an amplifier.


As the volume knob was turned clockwise the pitch decreased.


The explanation offered was that the harmonic distortion of the amplifier ie 880Hz which is a bad octave to our brain and therefore the brain now perceives the fundamental lower than 440Hz!


The explanation offered by Albert Ketentzian is an interesting one.


In fact this also happens without an amplifier, using just a tuning fork. (See Sound and Hearing - SS Stevens).


Does this sujest the nonlinearity of the ear brain as the cause?


Non linearity may shift the point at the basilar membrane in the same way that nonlinearity detects audio from rf AM radio waves as a shift in the DC point of a detecting electron tube, diode, or triode.


Do both phenomena of the title have a common explanation? Does the brain use the decrease in pitch as an electronic compressor amplifier sidechain signal to understand how loud a sound is and decrease its sensitivity?


Experimenting with a Casio MT-100 and playing the lowest F and then the highest shows that both notes sound lower in pitch when the volume is changed from quiet to loud.


Much more experimentation and a new theory would be nice.

The beauty of the Solina String Ensembke and other synthesizers

One very helpful feature is that they have a tuning knob.


So for high or loudly played notes for example, the player increases or stretches the frequency so that the note sounds correct to the human ear-brain.


On electric guitar this is done by bending notes and using the feedback from our brain to find the right amount of string bending in real time.


On iPad GarageBand for example it can be done by using the pitch bender wheel. It is funny that to make a very high C sound like a C it has to be bent more than a semitone up. This is how our brain perceives. There must be a reason for this.


In other words a high octave of 1000Hz is not 4000Hz. 4000Hz sounds very flat. And in fact 880Hz sounds a flat uninteresting octave of 440Hz. Especially if 880Hz is at high intensity. Our brain needs more than 880Hz! And good instruments like a Steinway piano do not have the 2nd overtone (2nd mode of vibration) of a 440Hz vibrating at 880Hz. This would make a wrongly sounding note. Like a cheap toy. The scaling of the strings is so arranged that the strings is so much tensioned before breaking so that the inharmonicity of the steel string make the 2nd overtone higher than 880Hz so that it sounds correct to our brain. This is the result of hundreds of years of piano evolution.


See also the nearby euroelectron posts.

Is the same note played by the finger shifted depending on whether it is pp or p or f or ff?

It should be as pitch (the brain perception) depends on intensity and not only on frequency.


This is why good musicians play by ear-brain.


And good conductors too.


And good synthesizer players-composers too. Each synthesizer is tuned according to how loud it plays and how high it plays.


The ear brain is the judge. Not the frequency.

Η Κανελινα, η Lucy, οι μεγάλες έβδομες

Η Αγγλίδα γάτα, η Lucy, συνέχισε να κανει φιγούρα.


Άκουγαν ραδιόφωνο και ξαφνικά μπαίνει το τραγούδι Julia - Pavlov's Dog...


"Να, το αριστερό χέρι παιζει στο πιάνο Σολ, Ντο, Μι, δηλαδή Ντο ματζορε.


Και το δεξί χέρι Σι, Σι οκταβες.


Άρα το σύνολο ειναι Ντο μεγάλη έβδομη αφου το Σι απέχει 7 φυσικές νότες απο το μπαςο"


Τρελάθηκε η υπομονετική χελώνα.


Η Κανελινα που ειναι πολυ έξυπνη δεν καταλάβαινε τίποτα και έβαλε τα κλάματα τρέχοντας προς την ήρεμη παραλια με τους σοφούς γλάρους .


Οι σοφοί γλάροι ήταν πανω στον αγαπημένο τους βράχο που ξεπροβάλει απο τη θαλαςςα. Ειναι απιστευτο ζευγάρι και δεν τσακώνονται σχεδόν ποτε. Μόλις είδαν την Κανελινα γέλασαν και της σκούπισαν τα δάκρυα με τις κατάλευκες φτερούγες τους.


Μην ανησυχείς στην Ελλάδα μόλις ξεκίνησε μάθημα που εξηγεί τις συγχορδίες.


Στη μουσική οι νότες απο μόνες τους δεν λένε σχεδόν τίποτα. Ειναι σαν γράμματα στο αλφάβητο. Εξαλου ειναι μονο 7 οι νότες.


Σημασια εχει πια νότα ειναι πριν και πια μετά και αυτο ειναι η αρχή μιας μελωδίας. Οπως γράμματα πριν και μετά δημιουργούν λέξεις.


Οι νότες απο μόνες τους δεν δίνουν σχεδόν καμια πληροφορία.


Ειναι ο συνδυασμός τους που δημιουργεί τα χρώματα ποικιλομορφίας στη μουσική και στην αντιληψη μας.


Στην ψυχή μας.


Για παραδειγμα ενα Σι απο μονο του δεν μας λέει πολλά.


Ενα όμως Σι και μετά ενα Ντο και μετά ενα Μι δημιουργούν το χρωμα της συγχορδίας Ντο μεγάλη έβδομη.


Αυτες οι νότες ακούγονται στην αρχή του Julia. Υπάρχει και ενα Σολ.


Οταν 3 η 4 διαφορετικές νότες ακούγονται μαζι ταυτοχρονα αυτο λέγεται συγχορδία.


Η συγχορδία Ντο μεγάλη έβδομη ειναι λοιπόν για παραδειγμα Ντο μπαςο, Σι το οποιο ιεραρχικά ειναι 7 νότες πανω απο το μπαςο, και Μι που ειναι διάστημα 3ης πανω απο το μπαςο για να ακούγονται ολα εύηχα. Οταν ακούγονται ολα αυτα μαζι η συγχορδία ειναι η Ντο μεγάλη έβδομη η C major 7th οπως λέγεται στα αγγλικά. Εχει και την πεμπτη ιεραρχικά πανω απο το μπαςο που ειναι Σολ.


Η Κανελινα είχε αρχίσει να πετάγεται απο την χαρά της.


Στο chorus του Julia εκει που λέει "Please, please see" η κυρια φωνή τραγουδάει Σολ. Το μπαςο παιζει Ντο. Και η χορωδία τραγουδάει Μι με Σολ, μετά Σολ με Σι και ενα συνθεσάϊζερ παιζει ψηλα κάποιες απο αυτες τις νοτες. Παλι Ντο μεγάλη έβδομη αφου το μυςτικο της μουσικής ειναι ο συσχετισμος του μπάσου (η βάσης απο τα Ελληνικά) με τα υπόλοιπα συνηχουντα. Και έχουμε μια απο τις πιο όμορφες συγχορδίες στον πλανήτη για ανθρωπους, γάτες και οχι μονο.


Μπορούμε να ακούσουμε την Ντο μεγάλη έβδομη και στο αργό μερος του Confutatis του Mozart. Εκει που τραγουδάνε οι γυναίκες. Κάποιες απο αυτες σε ενα σημείο τραγουδάνε Σι, κάποιες Μι, και το μπαςο Ντο. Περισσοτερα μπορείς να μάθεις στο YouTube βάζοντας Leonard Bernstein young people's comcerts. Επισεις στο βιβλίο του Bach που αναφέρεται στο τέλος, που προέρχεται απο το βιβλίο του Niedt το οποιο μελέτησε ο Bach.


Η Κανελινα πετάχτηκε απο τη χαρά της.


Σχεδόν είχε δακρύσει, τώρα απο χαρά όμως. Έτρεξε και τους φώναξε όλους και άρχισαν να χορευουν, να τραγουδούν και να κανουν μπάνιο στην μαγική παραλια κατω απο τις αστραφτερές ακτίνες του Ηλιου της Αφοβιας. Του Απολλωνιου Ηλιου που δεν αφηνει καμια σκια στην Αλήθεια.


Πηγη:
http://normanschmidt.net/scores/bachjs-general_bass_rules.pdf

Pleiades Electra III?

An output transformerless headphone amplifier could be made with EF183.


One EF183 triode connected per channel.


The relatively high anode current, of the order of a few milliamperes at a low anode voltage indicates a low output impedance, since Z=V/I.


The anode current can pass directly through high impedance headphones just like on Pleiades Elektra headphone amplifiers.


Operation can be at 12V supplying both heaters in series and anodes.


A resistor of the order of 1MΩ from anode to grid makes operation possible.


The signal is capacitor coupled to grid.


Cathodes are connected to ground and battery negative.

The EF183 as battery powered power amplifier

At your risk. Use all safety precautions. Including a suitable fuse in series with any battery for fire hazed protection in case of short circuit. Protect your ears by all ways possible. Keep volume down.


This is a circuit very similar, practically identical with the Pleiades V6 pre preamplifier operating at 3.6V.


The cathode is connected to ground. The anode, suppressor, screen grid connected together.


A SONY portable CD player line out was connected to grid through a 1μF capacitor.


The battery Vb is connected to anode through the primary of an output transformer. The transformer is a Saratoga Industries, 5KΩ to 600Ω or 4 Ω from a Collins receiver. A few inch full range speaker was connected.


The sound was faint and distorted. When a 10MΩ resistor was connected from anode to grid the sound was much more louder and clearer.


Changing to Vb=18V made a vast difference together with changing Rag from 10MΩ to 5MΩ and then to 1 MΩ or 470KΩ. Anode current was approximately 6mA with Rag=470KΩ. It was found strange that when the 470KΩ was connected from anode to grid, (one end of it to 18V), the grid voltage became 300mV positive but the tube still operated with the some quality of sound. Using 1MΩ (if it is correctly recalled) the grid voltage is slightly negative.


The sound was clean and could be heared in a living room at very low volume and excellent high frequency quality.


This indicates that the EF183 can be an excellent headphone amplifier. And an excellent line amplifier.


Therefore a Pleiades preamplifier can be built with a few stages of EF183 amplifying the faintest sound with low noise and bringing it to pro line level.


It may be possible with just 12V supplying everything.


The front end stage may be better operated with 3.6V including heaters for low noise and maximum information extraction (see other euroelectron posts on the Pleiades V4, V5, V6 preamplifiers.


Further experiments can lead to a nice stereo power amplifier. A step could be increasing the anode voltage. Other suitable tubes may be the 12SK7 which are varimu and high gm too.


The 12K5 has also to be tried as a power amplifier driving a loudspeaker. It operates in an amazing loud and high quality way on the Pleiades Elektra II headphone power amplifier with no components other than one electron tube per channel.


Also an output transformer less headphone amplifier could be made with one EF183 per channel. The relatively high anode current, of the order of a few milliamperes at a low anode voltage indicates a low output impedance. The anode current can pass directly through high impedance headphones just like on the Pleiades Elektra headphone amplifiers. Operation can be at 12V supplying both heaters in series and anodes. A resistor of the order of 1MΩ from anode to grid makes operation possible. Signal is capacitor coupled to grid.


Reference:


On preserving the transconductance of electron tubes at anode potentials as low as 3.6V - euroelectron blogspot

The EL84, PL84 power amplifier at 12V did not operate

Cathode was connected to ground.


Anode through an output transformer to Vb. The transformer is a 5KΩ to 600Ω or 4Ω. The speaker connected a few inch full range.

.
The input signal from the line out of a Sony portable CD player was coupled to the grid through 1 μF.


There was no sound. Connecting a 10MΩ from grid to ground or cathode still no sound.


When a 10 MΩ resistor was connected from anode to grid, sound started coming out but very low and distorted. If memory is correct a 5 MΩ was tried too with not much improvement. It cannot be recalled  if a 1MΩ was tried.


Vb was changed from 6V to 12V. There was 3x improvement but still the result is unusable.


It was found strange that if the grid voltage was monitored it was steady at 5V. It did not drop to - mV    when the cathode was heated as it happens on the EF183. This indicated the grid could not attract electrons through the Rag otherwise there would have been a voltage drop from the current flowing through 10MΩ. Is there a voltage threshold? Should a higher voltage be carefully tried? (The tube was checked to operate properly on a Dansette record player).


The EL84 was substituted by the EF183, triode connected. The EF183 allows connection of the suppressor grid to the anode. It is a vary μ, high gm electron tube. There was dramatic improvement. See the next euroelectron post.

Η Κανελινα, η Lucy, η παράγωγος συναρτησης

Η Κανελινα και η υπομονετική χελώνα παραγωγιζαν συναρτήσεις χωρις όμως να καταλαβαίνουν τη φυσική τους σημασία.


Που εφαρμόζονται ολα αυτα;


Ήρθε το καλοκαιρι και η φίλη τους η Lucy η γάτα απο την Αγγλία και τους έκανε φιγούρα.


"Βλέπετε τώρα που η χελώνα ειναι σταματημένη. Η συναρτηςη της απομάκρυνσης της απο σταθερό σημείο ειναι σταθερή συναρτηςη ως προς τον χρόνο. Η πρωτη παραγωγος ειναι λοιπόν 0 οπως και η ταχύτητα της.


Βλέπετε εγώ πως τρέχω. Η απομάκρυνση μου απο σταθερό σημείο αυξάνει γρήγορα. Αν κανετε γραφική παράσταση της απομάκρυνσης μου ως προς τη μεταβλητή του χρόνου η κλίση ειναι μεγάλη οπως και ταχύτητα μου που ειναι η κλίση η αλλιώς η πρωτη παραγωγος.


Βλέπετε τώρα πως επιταχυνομαι. Η ταχύτητα μου μεταβαλεται γρήγορα ως προς τον χρόνο. Η επιτάχυνση είμαι έξ ορισμού η πρωτη παραγωγος της ταχύτητας. Άρα η δεύτερη παραγωγος της συναρτησης που δίνει την απομάκρυνση μου απο σταθερό σημείο."


Η υπομονετική χελώνα τα έπαιξε και η Κανελινα που ειναι και αυτη έξυπνη έβαλε τα κλάματα γιατι δεν καταλάβαινε τίποτα.


Έτρεξε στους σοφούς γλάρους στην παραλια να τους ρωτήσει.


Οι γλάροι έβαλαν τα γέλια, "μην ανησυχεις". Στην Ελλάδα ήδη ξεκίνησε προγραμμα που να συνδιάζει τα μαθήματα μεταξύ τους.


Ταχύτητα ειναι εξ ορισμού ο ρυθμός μεταβολής της απομάκρυνσης. Η μεταβλητή ειναι ο χρόνος, t. Πρωτη παραγωγος ειναι εξ ορισμού ο ρυθμός μεταβολής μιας συναρτησης. Άρα ταχύτητα ειναι η πρωτη παραγωγος της συναρτησης απομάκρυνσης ως προς χρόνο.


Αν για παραδειγμα κινητό απομακρύνεται σύμφωνα με τη συναρτηςη d(t)=2t, η ταχύτητα του ειναι η πρωτη παραγωγος, δηλαδή 2.


Η Κανελινα άρχισε να καταλαβαίνει και σκούπισε τα δάκρυα της. Κοίταξε το κινητό της και έβαλε τα γέλια.


Αν για παραδειγμα το κινητό σου απομακρύνεται σύμφωνα με d(t)=7t , αυτο σημαίνει οτι καθε δευτερόλεπτο εχει διανύσει επιπλέον 7 μέτρα. Άρα τρέχει πιο πολυ. Η πρωτη παραγωγος ως προς τη μεταβλητή του χρόνου ειναι 7. Δηλαδή τρέχει με 7 μέτρα ανα δευτερόλεπτο.


Η Κανελινα που ξεπέρασε το σοκ αντί για μεταβλητή x να βλέπει t, που στην πραγματικότητα ειναι αντίστοιχο πράγμα ήταν πια όλο χαρά.


Να θυμάσαι οτι εξ ορισμού η πρωτη παραγωγος της απομάκρυνσης ως προς χρόνο ειναι η ταχύτητα. Η πρωτη παραγωγος της ταχύτητας ειναι η επιτάχυνση παλι εξ ορισμού.


Εξ ορισμού η πρωτη παραγωγος της ενέργειας, ο ρυθμός μεταβολής της ενέργειας δηλαδή ειναι η Ισχύς. Η Ισχύς μετριέται σε joule ανα δευτερόλεπτο η Watt τιμώντας τον Watt.


Πετάχτηκε απο τη χαρά της η Κανελινα.


Και που τα ξέρετε ολα αυτα εσείς;


Βλέπουμε στο YouTube τις διαλέξεις ενός απο τους μεγαλύτερους νομπελίστες φυσικούς στη γη. Τον Richard Feynman.


Η Κανελινα ξαναπετάχτηκε απο τη χαρά της.


Φώναξε και και τον γάτο με την πραςινη κορδελα, την υπομονετική χελώνα και την Lucy και όλοι μαζι χόρεψαν το Aquarious - The Fifth Dimension (https://m.youtube.com/watch?v=06X5HYynP5E) κατω απο το φως του Ηλιου που δεν αφηνει καμια σκια στην αλήθεια.


Πηγη:
The Feynman Lectures on Physics - Addison Wesley
http://www.feynmanlectures.caltech.edu

Connecting many Pleiades V6 preamplifier together for signal summing

Would it work?


Just connecting the anodes together of many EF183 tubes inside the Pleiades V series battery powered electron tube preamplifiers.


See also the following post on connecting many Pleiades K117 preamplifiers to iPad.

Connecting many microphones to iPad or iPhone

Your own risk.

It may be possible by connecting many Pleiades K117 cable preamplifiers together in parallel.

It may be done by connecting a splitter headphone mic adaptor to iPad. It connects to iPad and provides 2 inputs. Or if a cable that provides separate connection for headphones and mic is used then 1/8in stereo splitters may be used for connecting many Pleiades K117 cable low noise preamps.

This effectively connects to drains of the K117 JFETs together. Addition of signals should be possible as JFETs have a relative high output impedance. So the signals would be summed as is done using summing resistors.

This technique can be seen done on the Bouyer ST30 electron tube amplifier, 2 anodes joined together:

http://www.eserviceinfo.com/preview.php?fileid=63214&mode=direct&ext=jpg

If it works then more than 2 mics could be combined by continuously splitting with more splitter adaptors.

If it does not work then microphones themselves can be connected in parallel series combinations and the output connected to just one Pleiades K117 cable preamplifier.

These principles apply to any device that can power an electret condenser mic.

The Pleiades K117 can amplify moving coil and ribbon microphones with amazing quality, it is open source and more information can be found on euroelectron blogspot including how to connect to iPad.

It would be nice to have many microphones, each close to an instrument and record live in real time at top quality Girl from Ipanema, Jobim, Gilberto, Phil Ramonne way.

Live, many instruments direct to 1 track in real time with top sound quality, using only the memory for one wave channel.


Maximum signal to noise ratio.


Minimal signal path.

A Beautiful Duet

Interlude - Siouxie and Morrissey
https://m.youtube.com/watch?v=9pC_FVOoJzQ


Siouxie and Morrissey are singing the same notes at the same fundamental frequency. Not the woman one octave higher.


Nice B flat major 7ths.


What a song.

Examples of music having the C major 7th chord

It is just C bass and E, G, B on the right hand all keys white and it sounds fantastic.


It sounds great when the key is E minor and not only.


Examples:


The Messiah symphony in E minor, introduction - Handel
https://m.youtube.com/watch?v=1Xo6NYLzO6g
At 0:37 the first time it appears


Breathe - Pink Floyd (in E Dorian)
https://m.youtube.com/watch?v=mrojrDCI02
At 2:14 the first time it appears


Come Undone - Jennifer Rush (in E minor)
https://m.youtube.com/watch?v=hclHNBtStUA
Appears firstly at 0:36


Julia - Pavlov's Dog
https://m.youtube.com/watch?v=k3KSpeiRPTc
At 0:02 (how beautiful), also when the chorus sings "please please see", at "ple...", (how beautiful).


We are the People - Empire of the Sun
https://m.youtube.com/watch?v=hN5X4kGhAtU
Where does the Cmaj7 appear?


More than a Woman - Bee Gees
https://m.youtube.com/watch?v=JLCs4q136qE
The Cmaj7 is in many moments in time...


Sugar - The Editors


Eagle - ABBA


Year of the Cat - Al Stewart


Where do C major 7ths come from?


Reference:


http://normanschmidt.net/scores/bachjs-general_bass_rules.pdf

Θα μ' εκπαιδεύσεις;

Ωραια, πες βρίσκουμε κάποια σαν εσένα.


Τι κάνουμε η οχι, για να παραμείνει ευτυχισμένη;

Ωραίο δεν ειναι;

Οςο και να ψάχνεις δεν μπορείς να βρεις κάποια σαν εσένα.

An example of song having the interval of 4th

Balamos - Enrique Ingelsias


For example when Enrique sings at the beginning "we dance" at "da" he sings SOL (G) whereas the bass is RE (D).


This is an interval of 4th as the melody note is 4 scale notes higher than the bass.


Very few songs use this beautiful interval.


It may give a sense of love and it may not be a coincidence that the 4th chackras is the one for the heart.


Is it a coincidence too that the 7th chakras, the intellect one, has a correspondence with the major 7th chords, made of the 7th note interval from bass to melody, that plays with our intellect?

Οι πιο όμορφες στιγμές οταν σε σκευτομαι

Does sea water effectively remove yellow stains from clothes?

At your own risk.


It has been done successfully on Gore base layer series.

Examples of songs having Varispeed on voice

Varispeed means the speed of magnetic tape when recording to by smaller than when reproducing.


This makes the voice younger and fresh.


Possible examples:


Moonlight Shadow - Mike Oldfield
To France - Mike Oldfield
Maria Magdalena - Samdra
I Have a dream - Abba
One and One - Robert Miles
Moi Lolita - Alizée
Christophe
Demis Roussos


Reference:


Interview of Michael Tretow, engineer of ABBA

Examples of songs containing 9th chords

For example:


Just hold me - Maria Mena
At the beginning, the bass is A and another instrument plays B. The distance between A and B is an interval of 9th.


Maria Magdalena - Sandra
When Sandra sings "time". At "ti" the melody is G sharp, and the bass F sharp.


Close to You - Bacharach, Carpenters
When Karen sings "birds" for example. At "bi" her voice is at D and the bass is at C.


Hey you - Pink Floys
The guitar playing oscillating between E minor 9th and D minor 9th.

Food that helps keep teeth clean?

At your own risk.


Would an almost raw olive cut in small pieces inside a salad do the trick? It seems the other part of the juice of the olive removes oil in an intense way.


See also the euroelectron post titled cleaning teeth with a fresh olive.


Also a freshly cut grape does the trick.

Meal preparing music

Key is A minor, at some point modulating to D minor.


Signature is 3/4.


Glockenspiel or high piano notes for melody.


Harmony notation is figured bass as in Bach's period.


- means note sustained.


A C E         A (ie A minor)
A C E
A C E         G 2 4 6 (ie G bass with A minor)
A C E
F A E         F 7 (ie F major 7th)
-  D C
B -  -           (Implied E ie E major but nothing played)
-  -  -


Repeat


Then D minor key


D E F      D    (ie D minor chord)
D E F       D
D E F        G7  (ie G minor 7th)
D E F        G7
D E F        B7    (ie B flat major 7th)
D E F        B7
E  -  -         A      (ie A major)
-  -  -


It may also have at some point F# and then modulate to G minor. The code then can be G, F6, E7, ie G minor chord, F A D, Eb G D (E flat major 7th).

Inspired by Alexandro's food preparing videos.


Public domain

Examples of songs in the Dorian key

Earth Song - Michael Jackson (A flat Dorian)


To get Lucky - Daft Punk (B Dorian)


Breathe - Pink Floyd (E Dorian)


An easy way to recognize a Dorian scale is comparing for example A minor and A Dorian.


The A minor scale has all the notes white. A B C D E F G A


The A Dorian has the F sharp (nearest black key to F). A B C D E F# G A


So when the bass is D on the A minor scale the chord defined is D F A, ie D minor.


Whereas on the A Dorian the D is D major, D F# A which is happy.


Similar correspondence for all other Dorians.

Jucé is a place when you can sit and drink your freshly made juice

Example of step bass and pedal chords like on Moonlight Sonata - L V Beethoven

A great example is:


Far from everything - Angelo, Emanuel Kosh remix at 1:00. The bass is descending but the chords are kept the same (sustained). Like on the beginning of Moonlight Sonata.


https://m.youtube.com/watch?v=izKYQuQjP9M

Example of 9th chords

Earth song - Michael Jackson, written in the key of A flat Dorian


At the chorus. Michael singing B (SI) and the bass is A (LA). The distance from bass to melody is an interval of 9th.


https://m.youtube.com/watch?v=XAi3VTSdTxU

Example of pedal bass at melody

Evergreen - Barbara


At the end of the song where Batbara sustains the note, and almost everything else keeps changing.


https://m.youtube.com/watch?v=X-Ro7baEa6w

Proposed play list for Nova Gea jucé

Big in Japan
Sweet harmony
You're my heart you're my soul
This girl's in love - Warwick version
Pavane - Ravel, original or Wlliam Orbit version
It's my party - Leslie Gore
Interlude - Siouxie, Morrisey
Lolita - Alizée
Far from everything - Mark F. Angelo
Jobim
Ενα πρωινό (Ανναπμελ) - Ξαρχακος
Μπαλάντα του ουρι - Χατζιδακις
Music to watch girls by - Conniff
Girl from Ipanema
Endless Love
California girls - Beach Boys
California dreaming - Mamas and Papas
Time of my life
Air - Bach
Souvenir - OMD
Freelove - Depeche Mode
Earth Song - Michael Jackson
Strawberry fields for ever
Papa oom mow mow
Greenfields - Brothers four
Evergreen - Barbara Streisand
Woman in Love
O mio Seniore - Vianello
Je reviens te chercher
Ti amo
Amore mio - Alessio
Lollipop - Chordettes
Un homme et une femme
A time for us - Ray Conniff version
Chi Mai - Morricone
To France - Oldfield
Tubular bells
Children - Robert Miles
Chariots of Fire
What a feeling
Fame
Agkistri - Hatzinasios
Η Ακτή - Σπανουδάκης
To have and not to hold - Madonna

Ειναι καλύτερος ο κόσμος που υπάρχει έστω μια σαν εσένα

The greatest thanks

To those who wake us up hundreds of times every month while we sleep, many times a night.


Being half awake half asleep is when imaginative ideas come.

Making drum patterns or drum loops with our mouth

Easy to program as our brain does the job of conveying what it wants.


It is very easy to tune the drum sounds to the song, just like singing. If anything else is being monitored at the same time it would be at low volume as pitch perception of our brain depends on intensity and not only frequency [1].'


Had the open hi hat at the end of some bars come from the nessasity of breathing? If making drum sound patterns by mouth it is coming naturally.





Signal path used:


Male voice softly singing a drum pattern for the song Πως θα Ηταν - Beyer M55 HN - Pleiades K117 pre preamplifier inside 3 pin female DIN - iPad GarageBand - Sennheiser HD580


Reference :


[1] Sound and Hearing - S.S. Stevens, F. Warshofsky - Time Life books

Is the Beyer M55 the best microphone on the planet?

Who designed this microphone?


Signal path:


M55 HN - Pleiades K117 pre preamp inside 3 pin DIN female connector - iPad

Pleiades K117 inside 3 pin female DIN connector and Beyer M55 HN connected to iPad

Perhaps the most unbelievable sound so far.


The K177 JFET and 220Ω source resistor were connected inside a 3 pin female DIN connector.


The Pleiades pre preamplifier is as follows. On the left end of the cable the Pleiades K117 amplifier inside the 3 pin DIN female connector. On the right side of the red video cable a 1/8in male stereo jack.


So an M55 HN can be connected and low noise preamplified directly taking advantage of its high Z capability. This is done by an input transformer inside the mic.


The sound is so natural from vocals chords of singer to listener's brain. No EQ needed.


Low noise too.


Setup, signal,path:


Kitchen with tiles half way up and doors closed - male voice singing thé chorus of Πως θα Ηταν at the key of C minor - Beyer M55 HN at 1in - Pleiades K117 inside female DIN - Y headphone mic adaptor to 4 pin 1/8 Jack - iPad, GarageBand rec level at 6 - Sennheiser HD580

Recording and past

Recording and playback is about the past.


Even these words after they have been written they are past.


Why don't we spend more of our precious time with present, perhaps even future.


But somehow past can help us move. For example while building today the Pleiades K117 inside a female 3 pin DIN connector the song Love is a Many Spendored Thing - Ray Conniff version was listened to, too many times through headphones. This was to mask the ambient noise. It would have been impossible to concentrate without the song.


And hope too.

Analog simulation of magnetic tape saturation in reel to reel tape recorders

Would a ring core interstage transformer simulate this, being effectively 2 heads touching each other at the air gap.


The interstage transformer can be arranged to be driven at constant current rather than voltage by the high out impedance of an electron tube or JFET (it's output in series with a resistor). Usually a series high KΩ résistance is added in series even on vacuum tubes.


The head or (interstage transformer in our case) plays the role of the Pleiades filter. As frequency rises so does the voltage across it as the voltage drop from the driver stage is continuously reduced by the impedance of the inductor increasing (progressively less short circuit).


So there would be at high levels magnetic saturation at all frequencies. Not only at low frequencies as when using ordinary high inductance input transformers for microphones for example.


And the beauty is that the next amplification stage after magnetic saturation would have to high cut anyway (for flat frequency responce) or integrate.


This high cut rounds off the clipped high peaks. See also interviews on how Mile Oldfield produces his guitar sound or description of Orban analog FM processors and patents.


Is this one main reason why vinyl records and analog tape recording sound so nice?


Would an interstage transformer made for example with a Magnetec Nanoperm core simulate analog magnetic tape recording running at 60ips?


The beauty of analog simulation is that it runs in real time at the speed of light. Nature itself does the computing.


Or rather is.

Micro variations in analog recording

Is this another reason for analog recording sounding so nice?


There are micro variations at various angular velocities corresponding to different frequencies according to the many diameters of pulleys, pitch roller, shafts etc.


Non harmonic frequencies make a pattern that almost never repeats itself. Like planets rotating at different angular velocity therefore frequency.


These micro variations caress the basilar membrane.


In a similar way a Leslie speaker does due to the Doppler effect causing frequency variation.


But in a more subtle and almost random way.


Possibly equipment mocrovariations combined with musician microvariations make a Cartesian product of mocrovariations that never repeat. An example is the accordion and general sound on Speak Softly - Nino Rota, Ray Connif version.


There we have microvariations by the accordion player for example. The air is modulated. The distance of the accordion from the mic is modulated (phase modulation). We have countless reflections from the church, Columbia Studio at 30th street New York. The sound is sent to the store room acting as echo chamber (see Frank Laico interview on YouTube by AES). The return from the chamber is passed through an analog recorder in real time. Then it is combined with the live signal.


Tremendous number of microvariations added or rather multiplied together.


Is this another reason why these recordings can be listened to so many times and the interest of our brain is still there?


How can we create nice microvariations on 2017 without motors running on tape recorders?


One way could be handheld or suspended microphones for instruments, creating a very effective and subtle Doppler effect or phase microvariations. These are combined with the performer moving microvariatios. So this is already 2 degrees of freedom.


Another way is suspended speakers from the ceiling by a strong cable caring the signal. Rotating them and letting them oscillate by gravity gives another 2 degrees of freedom, a very interesting Doopler Leslie effect without motor noise and random too.


The bass absorbing panels can be suspended too and they oscillate at any moment of draft around the room. Reflections from them are phase modulated too in a combined random way.

Beyer M55 with Pleiades K117 pre preamplifier cable and iPad

Sounding natural or correct to listener's brain.


The MD21 HL sounds bass and treble heavy by comparison.


An ordinary electret headset at 0in sounded 10 times more noisy and the iPad rec level volume had to be turned to 10. It sounded sad and bass heavy.


The M55 sounded happy even at the low sung key, (A flat minor compared to C minor which was originaly used for making up the song).


Signal path, set up:


Kitchen with tiles halfway up and doors closed - male voice singing Πως θα ήταν at a low key - Beyer M55 HN at 1in - Pleiades K117 cable - Y adaptor from headphone and mic to iPad 4 pin 1/8in headphone- mic connector - iPad, GarageBand rec level at 6 - Sennheiser HD580

Pleiades K117 cable pre preamplifier with Sennheuser MD21 and iPad

The color of the cable is red, video cable, slightly longer than a meter.


On one side is the mini Tuchel connector. Inside the mini Tuchel connector is the Pleiades K117 low noise pre preamplifier. It consists of only a K117 JFET and a 230Ω source resistor.


The other dude if the cable is connected to a 1/8in mini jack. It can be connected to any mic input supplying power to electret condenser microphones.


Connection to iPad is made via a Y headphone, mic to combined headphone mic 4 pin adapter.


The Sennheuser MD21 HL microphone was connected taking full advantage of the high steeped up signal from the internal sept up transformer. The Pleiades K177 matches Aldo the high impedance to low to drive the iPad.


Sound quality is great. Undetectable hiss,


Signal path:


Kitchen with tiles and doors closed - male voice singing Πως θα ήταν - Sennheiser MD21 HL at 1 in - Pleiades K117 cable pre preamplifier - Y adaptor  - iPad GarageBand - Sennheiser HD580

Are electron tubes quieter than JFETs?

It has to be re measured.


When we think of a noisy electron tube preamplifier what we hear is not the tubes. It is the power supply 50Hz and harmonics noise, input transformer hum induced noise, possible other component noise etc.


There is not such noise if electron tubes are battery operated.


And there is a further advantage.


The Neumann U47 achieves low noise by operating the VF14 electron tube at low anode and heater potentials.


Why not further reducing these potentials?


This is done on the Pleiades V series pre preamplifiers operating with just 3.6 volts. This is made possible by a 3.9MΩ electron accelerator resistor from anode to grid.


JFETs are fantastic devices. They can operate with just 3 volts too. They do not need a heater voltage.


There must be research on electron tubes that operate wiltout a heater voltage.


Electron tubes possibly have much better gently overload peak limiting characteristics.


The good thing about simple circuits is that active devices like electron tubes, bipolar transistors or JFETs have an inherent flat bandwidth from 0Hz to possibly Megahertz.


For example electron tubes can go flat from 0Hz to Megahertz. They are extremely linear at small signals, and as explained above and in other euroelectron posts, they can be extremely low noise too.


The bandwidth on devices is restricted by the surrounding components. The reactance of capacitors and inductor depend on frequency. Even signal carrying wires close to the chassis by definition form a capacitor. The capacitor by definition tries to keep the voltage constant so the extreme high frequencies are reduced.



Reactance of components varying with frequency can be used to advantage when designing Pleiades filters For flat frequency responce from singer's vocal chords to listener's brain.


General reference:


Electronics - Neil Storey

The Pleiades K117 pre preamplifier terminated with a 1/8in stereo jack

Connecting the Pleiades K117 to iPad through a 4 pin headphone mic jack interminent connectivity and noise problems were frequently encountered.


The new version Pleiades K117 pre preamp with be terminated with a 1/8in stereo jack. So it will be compatible with everything that can be connected to electret mics.


The connection to iPad or iPhone will be with one of those nice Y adapters. The single 4 pin side is connected to iPad. At the other side it has a female headphone socket and a female mic socket. And it is very small barely larger than the connectors themselves.

The weak link in a music recording signal path chain

It may not be the microphone assuming a good microphone. Good does not mean condencer. Neither does it mean nessasarily expensive. It may be a condencer, crystal, dynamic voice coil, ribbon in alphabetical order.


It may not be the singer assuming a good singer. A good singer does not mean a loudly singing singer.


Could it be that the weakest links are the recording room and the pre preamplifier.


Assuming a room or space (without low frequency reasonance or reverberation, having for example vibrating panels) or even any space with no LF problems for example large spaces or infinite spaces (outdoors)...


The problem may be how quiet the room is.


A very quiet room reveals noise problems in the pre preamplifier.


A very quiet room, makes us feel relaxed. Our ears adjust, their sensitivity increases and everything sounds smooth and loud. The same should happen when recording in it.


The singer does not need to sing loud and does not need to listen loud to the backing track.


There are no nasty peaks in the voice and the end result is a very good modulation of the recording medium. Therefore it sounds loud, see: Sound on Sound making a mix sound loud.


The singer does not need to listen loud to the backing track so the singing is in tune. The reason is that pitch perception does not only depend on frequency but on intensity too, see: Sound and Hearing - S.S. Stevens.


All the above cannot happen unless the pre preamplifier is extremely quiet. If not there would be hiss.


Could it be that the limit of quality is the quality of the pre preamplifier in terms of lowest possible noise?

Revisiting Pleiades K117 pre preamplifier with iPad

It sounds fantastic as expected with so a minimal signal path. Just an input transformer a K117 JFET and a 220Ω source resistor.


Signal path:


Kitchen with tiles - male voice singing Πως Θα Ηταν - Shure SM58 Mexico at 1 in - Pleiades proximity compensating 30mH : 19H input transformer inside Neutrik female to male adaptor - Pleiades K117 inside female XLR - iPad (headphone mic connection) with GarageBand - Sennheiser HD580


There were some sibilant problems and the reasonance of the transformer could be heard as it was unterminated and possibly not as quiet as the Pleiades EF183 electron tube V series pre preamplifier but it sings too.

In the process of winding the output transformer of the Pleiades V6 micropne pre amplifier.

The magnetic core is the Nanoperm Nanocrystalinne Magnetec 070 core.


The wire thickness for the primary winding of the output transformer is Φ 0.1mm ie diameter of 100 μm.


The number of turns possibly 800 filling one complete layer. Approximately 50 turns are wound everyday. The full length of the wire is wound on a thin wooden stick that can pass through the Magnetc 070 core for ease of winding.

Preparing for building the Pleiades V6 battery tube preamplifier prototype

Serial number is according to date time code 17072112.


It will look similar to the Pleiades Elektra series headphone electron tube battery power amplifiers.


It will consist of 2 parallel anodized aluminum reinforced panels spaced at 4in by 4 aluminum columns.


So the enclosed defined will be 5in x 2.5in x 4in.


The back panel will contain 2 Neutrik XLR in, out for each channel, on each side.


At the middle there will be a high quality AA battery holder with no rivets for 3 batteries.


Below it there will be a fuse holder.


On the front panel there will be:


The screw structures supporting the 2 EF183 triode connected electron tubes.


The screw supporting the 2 Magnetec Nanoperm Nanocrystalinne ring cores making the input and output transformer for each channel.


The flush mounted Velleman on off switch for the heaters only, connected to the fuse holder. This
will insure the smoothest and noiseless turn on and off of the front end microphone preamplifier.

The plate or anode circuits will be supplied directly by the fuse holder.


Somewhere in the front there will be the Pleiades logo with the star. And at the back the serial number which be effectively a military type year, month, day, hour time code, ie date time code.


The anode will be supplied by less than 4V through the primary of the the output transformers. The cathodes will be connected to 0V. A capacitor will couple from the secondary of the input transformer to the grid .


Operation is made possible by a 3.9MΩ resistor from anode to grid for every channel. This will free electrons at such low anode potential. Cathodes will be deliberately under heated. Bass compensation will be done by fewer wire turns on the input and output transformer. This construction adjustment will aid flat frequency responce from vocal chords of singer to lostener's brain.


The above will insure the quietest possibly operation. More details on other euroelectron posts on the Pleiades preamplifiers including the V6 schematic.


One of the reinforced aluminum panels was original made with 4 holes so that XLR female to male adaptors can pass through containing inside them input or output? transformers. The chassis Neutrik male or female connectors would be supported by screw structures near the other panel inside of the enclosure.


A mono prototype may be built as an alternative construction in an die cast aluminum box.


It would be nice if all components which are few anyway could be mounted in the direction of the signal path, topologically as on the schematic.


Everything could be inside the die cast box including the tube, the tube base supported by longer screws, nuts on each side and the box upside down so that everything could be seen from above.

A great bread, ενα φανταστικό ψωμι

Ειναι το Κασιμης ολικής άλεσης με προζύμι, χωρις λάδι.


Το πουλάνε super market.


It is whole wheat with yeast and no oil made near Athens by Kasimis.

A way to clean teeth with a fresh olive

Your own risk.


The Curaprox made in Swiss ultra soft toothbrush with sea water method after every meal is described on a previous euroelectron post.


This is about cutting an immature green olive. It happened by accident. The experiment was on trying to see if the most pure virgin oil could be felt together with the other juices of the olive.


Puting it into mouth and beginning biting it slowly as it is very bitter.


It was eaten very very slowly in about half an hour. It way kept in mouth all that time until the kernel was completely clean. It may not be suitable for the stomach. Eating whole wheat bread made with yeast and no oil  afterwards helped neutralize  pH ?


For some reason the teeth and mouth afterwards felt so clean and smooth without any oily substance in a miraculous way. A similar feeling to having done the thoroughest teeth cleaning in one's life.


Why?

Εργοστάσιο για ταχίνι ολικής Αργουδελης, Argoudelis Tahini Factory

Υπάρχει εδώ και παρα πολλά έτη το εργοστάσιο για ταχίνι και οχι μόνο Αργουδελης στα Καμίνια, Πειραιάς.


There is in the area of Kaminia, Piraeus the factory of Argoudelis making since many years ago tahini and not only.

Sesame with hulls contains much more calcium

Reference:


http://www.whfoods.com/genpage.php?tname=foodspice&dbid=84

Non cooked food

At your own risk.


Is it best to avoid cooked food?


There must be great ways. For example, oat flakes, with sesame, black raisins, various nuts,...?

Why cooked food gets brown, or the Maillard reaction

It is interesting to read about the Maillard reaction, on Wikipedia for example:


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


There are byproducts that are not very kind to our health.

C'est plus difficile de ne pas faire

Ειναι πιο δύσκολο να μην κανουμε κατι

It is more difficult not doing something.

Πως θα ήταν ένας διαγωνισμός τραγουδιού στο ΚΠΙΣΝ;

Ιςως οχι και πολυ καλη ιδέα.

Attention to milk?

Is it any true that cows are injected with antibiotics everyday?


Is it true that stopping milk cures asthma?


Is it true that some children who get ill very often are cured when they stop drinking milk?


Is it true that the more skimmed a milk is the most osteoporosis it causes compared to the full fat milk which never finds its way to super markets?


Is tahini or sesame a good alternative for calcium?


The mother's milk with love has the reputation of being the best on earth and this for the first part of our life.

Ρωτώντας ενα φωτομοντέλο για μια καλη ποιοτητα τροφής μια πιθανη απάντηση ειναι το ταχίνι;

If asking a model what is good food a possible answer may be tahini?

Is sesame the best food on earth?

At your own risk.


It should be even better than tahini as it is not heated, directly from nature.


One can buy whole grain sesame.


A great source of oil, protein, hydrocarbons.

Sears Silvertone 5240

A nice electron tube reel to reel tape recorder.


It has an add it function. This means while listening to track 1, track 2 can be recorded.


It is a 1/4 track tape recorder.

Tape recorder lubrication

At your own risk.


Most manual direct to apply oil sparingly.


A great help is the thinnest possible syringe and a long needle.


The beatings of the motor can be lubricated, the beating of the capstan etc.


A suitable oil may be Fuchs Renolin D10.


To reach most difficult spots one can improvise with shrinkable tubing fitted at the needle.


This lubrication tip comes from George at Radio Katoumas Athens electronics shop.

Είμαι ο πιο ευτυχισμένος άνθρωπος που σ' εχω γνωρίσει

Τι ειναι τεχνολογία

Να κανουμε πολλά με λίγα


Μιχάλης

Πως να κατασκευάσετε έναν με λάμπες η λυχνίες (λαμπατο) προενισχυτη μικροφώνου

Με δικη σας ευθύνη.


Χρησιμοποιούμε καθε μέσο προφύλαξης συμπεριλαμβάνοντας οπωςδηποτε ασφάλεια σε σειρά με την μπαταρία.


Σωστός όρος ειναι ενισχυτής με σωλήνες ηλεκτρονίων.


Το σχέδιο θα το βρείτε στο κοντινό χρονικά euroelectron post με τίτλο Pleiades V6 schematic.


https://euroelectron.blogspot.gr/search?updated-max=2017-07-14T00:33:00-07:00&max-results=7

Πως να φτιάξετε προενισχυτη μικροφώνου με σωλήνες ηλεκρονιων που λειτουργεί με μια μόνο μπαταρία

Με δικη σας ευθύνη.


Οταν χρησιμοποιούμε μπαταρία παίρνουμε καθε προφύλαξη και οπωσδήποτε χρησιμοποιούμε ασφάλεια συνδεμένη σε σειρά.


Το σχέδιο και περιγραφή βρίσκεται στο κοντινό χρονικά euroelectron post με τίτλο Pleiades V6 schematic.


https://euroelectron.blogspot.gr/search?updated-max=2017-07-14T00:33:00-07:00&max-results=7

What is Technology

Technology is doing more with less


Michalis

A useful wire diameter for winding Pleiades transformers

A typical commonly used diameter for the high number of turns winding is 0.1mm.


This fills a few hundred turns on the Magnetec 073 on one layer. Usually just one full layer is used.

Switching on Pleiades preamplifiers without any noise

This simple technique can be used on the Pleiades V series electron tube battery microphone pre preamplifiers or  the Pleiades Elektra no component headphone battery powered electron tube power amplifiers.


It assures gradual turning on or off without glitches, transients. This is the most sensitive and perhaps important part of a sound recording system. The front end amplifier. Anything wrong happening here will be  subsequently greatly magnified by the rest of the system.


The battery is always connected to the anode circuit.


There is no current flow as the cathode is cold.


A switch supplies power to the heaters.


The cathode temperature begins to increase and the low noise amplifier comes to life.


It also serves as a check. If when switching off the heaters the signal to noise ratio starts to increase it means that the cathodes must be made even more underheated.


These circuits are operated deliberately at lower cathode temperature. For example the EF183 original designed for 6.3V may be supplied by only 3.7V.


Underheated cathodes take more time to make the amp operate.


Same as on the Neumann U47 or the AKG C12A microphones.


One has to wait many seconds for electrons to start flowing from cathode to anode to have sound beginning to coming out.


And one can hear the miracle of nature, the sound coming in and noise gradually almost disappearing.


Great fun.

Ευτυχία που υπάρχεις

Ακομη και χωρις τίποτα εχω τα παντα.

Different versions of the Pleiades V preamplifier

V(-1). Was it made before or after V0? It uses just an 7025 electron tube. A Sowter input transformer direct to grid (no capacitor) and a Stancor military output transformer directly to anode. A cathode resistor of 470ohms reduces the positive potential from the cathode electron cloud. One 9 volt supplies the heaters with 5V through a 7005 regulator. Another 9V battery supplies the anode with 9 volts. Everything with drawer battery holders on one box. By having the anode battery in all the time and snapping in the other battery soft start and stop in ensured. Fuses should have been added. It sounds as if you are about to take off. Great for soft voice singing.


V0. It started existence on around 2000 as a 6V ECC86 DI preamplifier. In a very small aluminum diecast and then grey primer painted box. It did not sing so sometime during the last years after the Pleiades discovery of using a resistor from anode to grid to free the electrons it has been converted to an ECC82 12V powered low noise pre pre amp DI. Most of the other components are still there. A 10MΩ resistor from an earlier version connected to ground is now connected to anode and the other side left to grid. The cathode of the 1/2 ECC82 used is connected to ground. The small military transformer on top of the box is connected directly to anode. So it is a single ended class A pre amplifier. Class A means electrons are flowing all the time. The input 1/4in mono female is coupled to grid through a 10nF capacitor. This is all. Very similar to Pleiades V6. The output transformer winding inductances are 29H to 1.1H. It is an Admiral TF1RX11YY SC-B-91267, 20,000Ω to 600Ω. The 600Ω winding is connected to a Neutrik chassis male output. The V0 has been fed by a Beyer M55 and external input trasformer. It's output was connected to EMI RS61. It sings. There may be photos of it on another euroelectron post.


V1. It is using an electrometer tube (CV2269) and operates with just a 1.2V battery. The idea of using an electrometer tube came after a conversation with Sean Davies on his use of electrometer tubes for condencer microphones. It was first observed by accident that returning the grid circuit to the positive terminal of the heater battery made a vast difference in anode current. Then an accidental short circuit of the plate circuit proved that the tube could operate with no Vb. Effectively it was the heater battery supplying both heater, grid and plate circuits. Not very low noise. And microphonic too.


V2 version with an 12AU7 or ECC82. 12V powered. Initially 10MΩ was used form grid to cathode. The cathode was connected to ground. After the V4 experiments a less high Megohm resistor is now connected from anode to grid.


V3 experimental gig with breadboard? Or a small box with a circuit like V4 and external battery supply? Or a little cast aluminum box being much before V1 with ECC86. Never worked quite well. It is now with EF183 and uses the already installed military output transformer.  A short of DI high Z in low Z output. The output transformer successful operation led to V6.


V4 EF183 single stage with no input or output transformer. It is a 10KΩ anode follower with a 3.9MΩ anode to grid resistor to free electrons and provide a normal transconductance. Initially a 4.8V supply of 4 AAA batteries was used for both heaters and anode. As of now it is just 3 of them giving approx. 3.7 volts and although gain is less the noise performance sounds still better. The EF183 is triode connected.


V5 A 2 stage EF183 pre preamplifier. Only input transformer using a Magnetec Nanoperm core. Same principles as on V4. Using two li ion 3.7 batteries in series and a fuse for the series connected heaters and anode supply. The 7.4V feed the anode circuits. Very low noise and juicy sound too as the second electron tube is now pushed by the first stage. Originally designed for microphones such as the Electro-Voice RE16. It sounds great on electric bass too when it is connected to the 5H secondary of the input trasformer. The 5 Henries inductance in parallel with the pickup creates a Pleiades filter compensating for excessive bass to brain perception and making the electric bass full of clean bass midrange and treble detail.


V6 similar to the Pleiades V4 but with no 10KΩ anode resistor. It has an input and output transformer. When the heater voltage is reduced to the sweet point the singing sound becomes so alive it is frightening.


V7 not yet specified. It may be two electron tubes and an interstage transformer playing the role of 2 magnetic heads with their airgaps touching. Intended for analog simulation of analog high speed tape recording. The rising frequency "recording" characteristic and the low pass "reproduction" characteristic creating instateneous peak limiting with rounded waveform. The interstate transformer is driven to soft saturation. Constant current operation of the primary of the interstate transformer is automati sly arranged by the high Z out of the tube driving a low inductance inductor. A Pleiades filter as in tube tape recorders where a high Z out drives the magnetic head.

Repeatedly writing improves writing skills

Same with everything.


It is the flight hours that matter.

Μαζι σου αισθάνομαι σαν να είμαι παιδι και ερωτεύομαι

Analog Electronics is digital Electronics with infinite number of bits?

An analog signal is defined as a signal that can take all values between 2 values.

Mathematics is computing with infinite resolution?

Pleiades V6 Schematic

This is the URL:
https://farm5.staticflickr.com/4262/35858046756_bbcd5097c5_k.jpg[/img






The Pleiades V6 is an electron tube ultra low noise microphone booster preamplifier having a single tube powered by just one li ion 3.7V battery (more attention is needed with li-ion batteries, 3x 1.2V NiMH are fine). Operation of the electron tube is in class A. Class A operation means by definition that electrons are flowing all the time. This achieves the lowest possible distortion for small signals. At large signals the Pleiades V6 may behave as a soft overload curve electron tube mastering amplifier, peak limiting at almost the speed of light.


The Pleiades V6 is designed to make a dynamic moving coil microphone or a ribbon microphone sound in real world at least as loud, sensitive or low noise as a condencer microphone. The output of this front end amplifier is to be connected to the input of a microphone preamplifier as one would connect a Neumann U47 microphone.


Circuit description or what each component does:
The low impedance microphone signal in the form of electrons dancing to the music is stepped up by the input transformer to a value comparable to that of a condenser microphone capsule. The coupling capacitor passes the signal but does not let the DC voltage assumed by the grid to be disturbed by the transformer. The battery supplies the heater with 3.7V. As the cathode is heated electrons boil off and the cathode becomes positive with respect to grid by the missing electrons. In other words the grid becomes negative wrt cathode. Electrons would be traped unable to travel to the low potential anode but the accelerating potential supplied by the 3.9 Megohm resistor from plate to grid frees electrons and make operation possible. The grid voltage is now close to O volts but still a little negative wrt cathode. The signal supplied by the capacitor (22nF is fine) can now be amplified as on electron tubes operating at much higher anode potential. The cathode is connected to ground and the negative terminal of the battery. The positive terminal of the 3.7V battery is connected to the anode through the primary of the output transformer with minimal voltage drop. The secondary of the output transformer brings us back to low impedance for connecting to the outside world. Electrons at the secondary output dance to the music at greater amplitudes and in a way that keeps frequency response flat to our brain, (see following paragraph). The tube is the EF183 vari mu high transconductance pentode, triode connected.


Bass compensation (reduction) for the proximity effect, Fletcher-Munson, voice effort curves can be built in by reducing the number of the transformer primary winding turns further simplifying the construction.


Suitable transformer cores are tape wound Nanoperm Nanocrystalinne ring cores by Magnetec. Input or output transformers can by correct choice of low turns compensate for the above effects and therefore create flat frequency responce from vocal chords of singer to listener's brain. This is the principle used in the Pleiades transformers. They also provide isolation, RF rejection, balanced and low impedance input and output. The input impedance of this electron tube in the Pleiades configuration at the grid terminal is typically 100ΚΩ. Normally nothing too elaborate should be used for the transformer windings. Just a symmetrical geometrically primary and secondary winding. Preferably one layer of each winding and the number of turns for full layer arranged by the thickness of the insulated wires used.


Cathode temperature can be optimized for maximum signal to noise ratio by adjusting the heater voltage. (Much like exoerimenting on the best temperature for baking amazing croissants made with butter and not vegetable or palm oil or palm fat having a reputation of clogging arteries).


The operation at a so low potential is made possible by not biasing the electron tube 2 times negatively, one internaly by nature and one by external components. Akowledgement to Hliana Stalika for insisting that the grid should not be negatively biased for freeing the electrons.


The anode to grid resistor counteracts the internal by nature negative bias. Resultant bias then becomes close to 0 but still negative. This allows the electron tube to have a normal transconductance at such a low anode potential.


The amplifier is extremely quiet, having virtualy no secondary electron emission effects at such low potential and temperature. The triode connected EF183 is deliberately underheated as is done on the VF14 electron tube of the Neumann U47 microphone.


Pleiades concepts or schematics are public domain.


References:


On preserving transconductance of electron tubes at anode potential as low as 3 volts - euroelectron blogspot


Operating features of the Audion - Edwin Howard Armstrong


"The Secret of Hollywood" - Sound Picture recording and reproducing characteristics - D.P. Loye, K.E. Morgan - Journal of society of motion picture engineers


US patent 1,349,252 - H. D. Arnold


Tubes vs Transistors, is there an audible difference? - Russel O. Hamm - Journal of the Audio Engineering Society

Measuring radio audience in real time

Can an electronic meter be made that:


Senses micro variations at the load at the output of the transmitter?


The more radios are tuned to a station the more the drop in voltage at the transmitting antenna. The more the power drawn from the transmitter.


Change of impedance matching?


Can these principles be engineered for audience measurement in real time?

Why does B minor sound so nice?

Who knows?

What to do when you grow up?

Becoming myself.

Τι θα γίνεις οταν μεγαλώσεις;

Οτι είμαι.

3 examples of often radio played songs in B minor

To France - Mike Oldfield


Moi Lolita - Alizee


I just died in your arms tonight - Cutting Crew


The B minor KEY or scale has every C to be  C sharp (the one step on the right black key from C) and every F to be  F sharp (the one step on the right black key from F).


The first two songs seem also to have the hit song ingredient Varispeed as used by ABBA and others, possibly Demis Roussos too to make the voice sound younger.


It is interesting reading interviews on how drummer Simon Philps self taught mostly and firstly taught by his father was shown by Mike Oldfield on using the console while they were making masterpieces like Moonlight Shadow and to France. He spent many many days trying to instal the mic inside the bass drum to get that beautiful beat sound. Mike Oldfield was using a rhyming dictionary as an aid to write these fabulous lyrics.


Not many songs are written in B minor. For some reason its chords sound so beautiful,

3 επίπεδα, 3 Levels

Wanting or not is value.


Must or must not is principle.


Can or cannot is rule-law.


By Michalis


Το ΘΕΛΩ η ΟΧΙ ειναι ΑΞΙΑ.


Το ΠΡΕΠΕΙ η ΟΧΙ ειναι ΑΡΧΕΣ.


Το ΜΠΟΡΩ η ΟΧΙ ειναι ΚΑΝΟΝΑΣ- ΝΟΜΟΣ.


Μόνο το πρώτο ειναι ΕΛΕΥΘΕΡΙΑ η ΣΥΝΕΙΔΗΤΟΤΗΤΑ.


Αναλογα με το πιο απο τα τρία κινείται κάποιος ΜΑΘΑΙΝΟΥΜΕ ευκολα το επίπεδο ΑΞΙΩΝ του. Οςο πιο πολυ μπερδεύει κανεις αυτα τα τρία τοςο δεν προχωρά στην ΑΥΤΟΤΕΛΕΙΑ.


Παραδείγματα - Examples


Βρίσκω την τσάντα με τα χρήματα ενός φίλου, να τα κρατήσω;


Το θελω η οχι ειναι αξία, το κάνω για μένα.


Το πρεπει η οχι το κάνω για τον άλλο - ηθική.


Το μπορω η οχι εχει να κανει με το αν με παίρνει να το κάνω η οχι - συνθήκες - νόμος - δεν θα μαθευτεί.


Με αυτο το σκεπτικό επινοήθηκε η ηθική και μετά οι νόμοι - επειδή οι άνθρωποι δύσκολα έχουν αξίες.


Το ίδιο συμβαινει σ'ολες τις επιλογές μας.


Πχ καριέρα.


Να πουληθω; Να κάνω κατι που...


1. Θελω η οχι (για μένα).


2. Πρεπει η οχι (για τους άλλους, μαμά, μπαμπάς, σύζυγος και λοιποί).


3. Μπορω να γίνω αυτο που θελουν οι άλλοι και να βγάλω και πολλά χρήματα γιατι με παίρνει.


Ειναι και αυτός ένας τρόπος να καταλάβεις τον άλλον γρήγορα και φυσικά μόνο το 1 ειναι αποδεκτό.


Όσοι κινούνται στο 2 η 3 ειναι δυστυχείς και κανουν συνήθως ψυχοθεραπεία.


Απο τον Μιχάλη

Je voudrais vous donner seulement du plaisir

Pleiades preamplifier schematic

On the nearby euroelectron post titled the Pleiades preamplifier.


See also the Pleiades V6 preamplifier

How to connect an electric guitar or bass guitar to iPad, iPhone or other devices with electret condencer mic input etc

At your own risk.


Details on the nearby euroelectron post on the class A one active device amplifier.

The best portable class A power amplifier?

Based on the circuit of K. Jones.


It is connected directly to the headphone out of portable devices.


It uses one active device only per channel. For example a 2N3055 bipolar transistor.


The full range speaker for each channel is connected to the collector being itself the load resistor.


The emitter is connected to ground.


A few KΩ resistor from collector to base provides bias.


The signal is applied to the base through a capacitor. If the music source output capacitor can withstand the DC voltage this capacitor can be omitted. So it is just a power amplifier with 3 components per channel including the speaker.


Battery (+) is applied through a fuse to the other speaker terminal.


Battery (-) is connected to ground.


The value of the base biasing resistor is determined experimentally by arranging with a variable resistor a not excessive DC displacement of the speaker cone.


The transistors should be used with a heat sink to minimize the risk of thermal runway.


Everything is in the same cabinet with both speakers and a 12V battery.


Or it can be made to an active speaker for each channel.


This is the Pleiades power amplifier.


Only 2 components per channel.


It operates in class A meaning electrons flow all the time through the active device. It sounds smooth, dynamic, loud. frightening realistic with no noise, no hiss and natural sweet sound.


Electrons flow all the time through each speaker too.


All protection should be exercised including a fuse next to the battery terminals for example.


A special version can be made for vocals, echo chamber use etc or for electric bass or guitar.


Pleiades concepts, designs, schematics are open source for anyone wanting to improve, build, sell.


Reference:


Audio Amplifiers - J. R. Davies - Data Publications LTD. London - chapter 7 - page 41 - 2 transistor miniature A.F. amplifier by K. Jones

The Electronics Aphorism

If it needs more than 4 components to be a circuit it is out.

The Pleiades preamplifier

The concept.


A high megohm resistor, typically 4 MΩ, connected from anode to grid makes electrons free so that the electron tube can operate at an anode potential of less than 6 volts.


Suitable tubes are ECC82 and even better an EF183 triode connected ie all grids except the control grid connected to anode. Tubes that operate best are very high transconductance (gm) and at the same time vari μ tubes therefore having remote cutoff. A perfect example is the EF183.


A typical value of input impedance of the Pleiades preamplifier is 100 KΩ which is ideal as a load for the secondary of a microphone step up transformer for example.


The heaters are supplied too with 3.6V, therefore the cathode is deliberately underheated. The low heater and anode voltage minimize any secondary electron emission effect, unblock the tube by negating the positive electron attracting cathode potential with respect to grid with the aid of Rag and ensure possibly the quietest amplifing operation ever achieved.


                                       +3.6V
                                     |
                                    <
                                     > 10KΩ
                           ____ < ______________ out
               4ΜΩ   |           |
                        <         _|_
                         >                EF183 triode connected
         in ----| |-- <----- - - -
                                   ___
                                     |
                ____ _______|_______________ 0V


                 The Pleiades preamplifier


To summarize, the grid should not be negatively biased 2 times; one internaly by what nature is doing and one externally of the electron tube if low voltage operation is desired.


Acknowledging Hliana Stalika for insisting that the grid should not be negatively biased inspired by a Montalk article relevant to preventing ourselves from negative bias and making us free.


Pleiades concepts are open source, public domain.


References:


Operating features of the Audion - Edwin Howard Armstrong


On preserving the transconductance of electron tubes at very low anode potential - euroelectron blogspot


The use of Multigrid tubes as Electrometers - J.R.Prescott

The class A one active device amplifier the best after more than 100 years?

It does not only sound so great, the schematic looks great too. It is just the 3 terminal active device and one resistor above and one resistor below. The Pleiades electron tube version uses just one resistor on top from anode to grid to make operation possible at a few volts. Simplicity at its best.


It is found on the best equipment on the planet. Examples are. The Neumann U47 microphone internal (front end) amplifier. The Fender guitar amp (first stage) preamplifiers. Triode single ended class power amplifiers. It is also used on the Pleiades pre preamplifiers and power amplifiers.


As mentioned again this circuit being inside a Neumann microphone U47 has been the closest in the signal path of singers like Leonaed Cohen, Madonna, the Beatles...The following example is a use of the Neumann U47 on the final version of the song Take on Me - a-ha doing justice to the angelic voice of Morten Harket. It is the electron tube U47 version, the internal amplifier using the VF14 tube at deliberately lower heater voltage as designer Georg Neumann had chosen. Earlier versions of the song were done with a U47 FET having many transistors in the signal path. The electron tube version uses just one tube from the output of the voice  capsule to the output cable of the mic. Warner executives were never happy with the older versions of the song and re rehired a 3rd producer. There are countless changes the remaking of a song can have. God as J.S. Bach used to say is in the details.
https://m.youtube.com/watch?v=djV11Xbc914


The more than a hundred years old circuit we are talking about is called anode follower or common cathode, collector follower or common emitter, drain follower or common source. The name depends on whether the active device is an electron tube, a bipolar transistor or a field effect transistor respectively


It is the bread and butter of electronics. And it can be built on a breadboard in a few seconds. Just an active 3 terminal device, one or two resistors and a battery.


Class A operation means by definition that electrons flow all the time through the active device. At small signals the active devices are extremely linear just like the earth around small distances. At large distances ie signals, for example at peaks they are non linear ie curved which is a great thing for audio. They artfully instantaneously limit nasty peaks and therefore keep the average signal high. And this gradual distortion increase as the input signal increases and euphoric harmonics are produced. Just like our ear do. Just like trumpets do. The louder we play them the more overtones they produce. This is a reason these amplifiers sound so big and dynamic yet gentle and buttery smooth near the zero crossing point of the waveform where the cream of the music signal exists.


It is ironic in our times that we spend so much energy and processing power to increase the average signal level and suppress the peaks with software. Class A circuits do this at the speed of light. And at the lower levels where the music juice is they are the smoothest and distortionless amplifiers on the planet.


It is interesting that some men, women are not afraid to keep things simple. Less is more. The circuit we are talking about is the first circuit one learns on good textbooks of electronics and it could well be the best on the planet.


It is nice that there are designers, electronic engineers, producers, musicians and listeners who trust the Beauty of such circuits. They have a-phobia and courage to trust the best judge. The human ear and brain perception. Our fantastic mind. And all this great as it is perceived sound amplified with just 2 or 3 components.


After all, the most healthy and best tasting croissants are made with just top quality flour, butter, salt, sugar and water. Not with vegetable oil, palm oil or fat which has a reputation of clogging the arteries and other unpronounceable ingredients on the small letter ingredients list of a typical packaging.


The same happens with great music composing. It is just 3 or 4 notes sounding together that make the miracle as can be heared and seen in the 4 Seasons - Vivaldi full score.


Does this principle hold in electronics too? If you need more than 4 components to make a circuit is it out?


It is great that Great inventors like Lee de Forest, H. D. Arnold, Edwin Armstrong, Allan Blumlein and others did so much for us. Conceived more than a 100 years ago their simple circuit is The circuit. This beautiful circuit can be seen for example inside the Neumann U47 electron tube microphone. And we can hear it on Leonard Cohen, Frank Sinatra, the Beatles, Madonna?



And when were in the nineties and everything around is op amps, one needs to have even more courage to say the truth. To say how nice the class A, simplest on the planet topology, sounds .


Such a man is J. Donald Tillman.


He proposed a simple use as a guitar preamplifier using just one JFET .


And not only this, he incorporated the JFET amplifier in the cable itself by building it inside the 1/4in jack that is connected to the electric guitar.


The description of this application is here:
http://www.till.com/articles/PreampCable/


And there, there is also a reference to US Patent 5,585,767 by Thomas W. Wright, Jr. Was Thomas W. Wright the first who had the great idea of building a preamp inside the cable connector?


The Pleiades K117 uses a similar circuit. Just a K117 JFET and a low source resistor. Originaly designed for moving coil or ribbon microphones it can be housed inside an XLR or Neutrik module. Or inside a mini Tuchel or Amphenol microphone connector. This makes possible direct amplification of an MD421 HN, MD21 HL or Unidyne III microphones exploiting fully their internal high impedance step up signal transformer. The signal to noise ratio achieved in this way is hard to believe.


As the Tillmen implementation can be phantom powered by a console so should the Pleiades K117 be.


The Pleiades K177 was designed to be directly powered by the mic input connector used for electret microphones.


Specifically the Pleiades K117 has its component values optimized for being connected directly to iPad. The iPad internal resistor becomes the load resistor .


For connecting an electric guitar or bass guitar the Pleiades K117 can be made inside a 1/4in jack and the other side connected to the iPad through the headphone - mic connector. A short cable with female headphone jack can be added for monitoring purposes.


It could be better if the iPad GarageBand has a low cut filter that can be disabled.


We could then set it to flat frequency response. And if we wish to cut the excessive bass frequencies perceived by out brain the best way on the planet is possibly an inductor in parallel with the signal source. This is the Pleiades filter used on microphones too to cut the excessive perceived bass. For example for an electric bass an inductor of 5 Henries across the bass guitar pickup removes all the confusion and brings out a deep as needed bass full with every high frequency mid and transient detail.


If wanting to use electron tubes a similar circuit can be made. If a 4 Megohm resistor is connected between anode (plate) and grid electrons become free. This makes operation of the tube possible at even 3 Volts. This is the Pleiades preamplifier. Very similar to a Neumann amplifier with much lower anode and heater voltage. In fact the electron tube is underheated deliberately as is done on the VF14 tube of the Neumann U47.


There is no reason why not having these ideas expanded and making a power JFET drive a directly connected speaker. The speaker being the load resistor itself. More information on this on the Pleiades power amplifier at other euroelectron posts.


To better understand these amazing and simple class A amplifier circuits more details can be found at the references.


The amplifier miracle.





References:


Tubes vs transistors is there an audible difference? - Russel O' Hamm - JAES


Electronics, a systems approach - Neil Storey



A practical introduction to electronic circuits - Martin Hartley Jones



Operating features of the Audion - Edwin Armstrong


Enchiridion (manual of life)- Epictetous


Tao te Ching - Lao Tzu


How to win friends - Dale Carnegie


Fringe knowledge for Beginers - Montalk


Applied Ekectronics - T.S.Gray - MIT


Audio Amplifiers - J.R. Davis - page 41 - 2 transistor miniature A.F. Amplifier by K. Jones


The 4 Seasons - Antonio Vivaldi - full score


http://www.soundonsound.com/people/ha-take-me


Neumann schematic:
http://www.davegroupjapan.com/ekoukoku2.html


Pleiades preamplifier schematic:



Pleiades V6 schematic:
https://euroelectron.blogspot.gr/2017/07/pleiades-v6-schematic.html


US patent 1,349,252 - H. D. Arnold