Burns B3 Guts

Posted: 9/4/2019 10:05:26 PM
Goño

From: Guadalajara, Jalisco, Mexico.

Joined: 7/5/2019

Hola, Edavid 

That part of the schematic is not quite correct.  I haven't completely traced the volume side, but U2 is a 74C14, and 1 section is used as the volume oscillator.  (I found it handy that the other sections were unused, when the first one was zapped by ESD.)
U1 is of course a CD4069UB.
The unit I have runs on 12V (from a 78L12 regulator).  Goño, are you sure yours runs on +5V?

El esquema es solo especulación mía, ya que no tengo un b3 y me base en las fotos y algo de imaginación, creo que tienes razón la parte del volumen no es correcta, lo estuve pensando después de hacer ese esquema, creo que usa un sistema similar a otros theremin, un oscilador y un circuito de resonante, por eso la inductancia, sobre la alimentación por lo que he leído si usa un regulador de 12 voltios, aunque yo lo probé el protoboard (solo el lado del tono) y puede funcionar con 5 voltios.

Posted: 9/4/2019 10:14:13 PM
rupertchappelle

From: earth

Joined: 5/8/2017

Somethings are best not seen, but heard.

Posted: 9/4/2019 10:17:18 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

Old tube radios and theremins were also “wildly air wired”, thus I’d see the B3 rather as a piece of artwork. That’s not the worst style for RF circuits (still sometimes used for microwave circuits) and everybody who can build such circuits, including Dan Burns, deserves deepest respect!

As a musician, one should care less about the innards of a theremin, but about it’s playability and expressivity. There are plenty of YouTube videos with Thomas Grillo, demonstrating and playing the various B3 models, proving that these are true and good music instruments.

Engineers and technicians have for sure different points of view, but what counts here, is the music. The B3 pro which uses basically the same circuit, just with a mute sensor key added, but comes in a larger wooden housing and with thicker antennas is a nice alternative to the Etherwave.

BTW: the schematics above are incomplete, there is the volume oscillator missing. Without it, all the discriminator circuitry afterwards makes no sense.

Posted: 9/4/2019 10:18:24 PM
edavid

Joined: 9/2/2019

El esquema es solo especulación mía, ya que no tengo un b3 y me base en las fotos y algo de imaginación, creo que tienes razón la parte del volumen no es correcta, lo estuve pensando después de hacer ese esquema, creo que usa un sistema similar a otros theremin, un oscilador y un circuito de resonante, por eso la inductancia, sobre la alimentación por lo que he leído si usa un regulador de 12 voltios, aunque yo lo probé el protoboard (solo el lado del tono) y puede funcionar con 5 voltios.

It is impressive that you were able to trace so much without having a B3.  I will post my own schematic when I get a chance - it is not much different.

Note, the B3 circuit does not use any inductors.

Posted: 9/4/2019 10:24:56 PM
Goño

From: Guadalajara, Jalisco, Mexico.

Joined: 7/5/2019

Old tube radios and theremins were also “wildly air wired”, thus I’d see the B3 rather as a piece of artwork. That’s not the worst style for RF circuits (still sometimes used for microwave circuits) and everybody who can build such circuits, including Dan Burns, deserves deepest respect!As a musician, one should care less about the innards of a theremin, but about it’s playability and expressivity. There are plenty of YouTube videos with Thomas Grillo, demonstrating and playing the various B3 models, proving that these are true and good music instruments.Engineers and technicians have for sure different points of view, but what counts here, is the music. The B3 pro which uses basically the same circuit, just with a mute sensor key added, but comes in a larger wooden housing and with thicker antennas is a nice alternative to the Etherwave.BTW: the schematics above are incomplete, there is the volume oscillator missing. Without it, all the discriminator circuitry afterwards makes no sense.

Usted tiene toda la razón, mi interés sobre el b3 fue que tiene un bonito tono y aparentemente se ve sencillo de reproducir.

Posted: 9/4/2019 10:28:33 PM
Goño

From: Guadalajara, Jalisco, Mexico.

Joined: 7/5/2019

El esquema es solo especulación mía, ya que no tengo un b3 y me base en las fotos y algo de imaginación, creo que tienes razón la parte del volumen no es correcta, lo estuve pensando después de hacer ese esquema, creo que usa un sistema similar a otros theremin, un oscilador y un circuito de resonante, por eso la inductancia, sobre la alimentación por lo que he leído si usa un regulador de 12 voltios, aunque yo lo probé el protoboard (solo el lado del tono) y puede funcionar con 5 voltios.It is impressive that you were able to trace so much without having a B3.  I will post my own schematic when I get a chance - it is not much different.Note, the B3 circuit does not use any inductors.

Me encantara ver su esquema o algunas fotos mejor tomadas, quedo al pendiente. 

Posted: 9/4/2019 11:22:52 PM
edavid

Joined: 9/2/2019

Here are some photos that I took - not really any better than the ones already posted.



Posted: 9/4/2019 11:56:06 PM
Goño

From: Guadalajara, Jalisco, Mexico.

Joined: 7/5/2019

Gracias Edavid, voy a darles una mirada penetrante a ver si logro deducir algo, aunque sigo viendo un choke del lado del volumen.

Algo así se me ocurrió que podría ser, con un cd40106 o similar, aunque no lo tengo muy claro.


Posted: 9/5/2019 2:57:48 AM
edavid

Joined: 9/2/2019

Here is my version of the pitch side schematic.  The pitch pot is 1K and the pitch trimmer is 5K.


Posted: 9/5/2019 4:30:14 AM
Goño

From: Guadalajara, Jalisco, Mexico.

Joined: 7/5/2019

Here is my version of the pitch side schematic.  The pitch pot is 1K and the pitch trimmer is 5K.

Tremendo Edavid, veo que no estaba tan perdido con los valores que utilice, intentare hacer una placa de prueba por la mañana. 

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