Hello everybody

Posted: 11/13/2017 6:59:00 PM
Oilspill

From: France

Joined: 11/13/2017

Hi to everybody here

since a couple of months i am reading here in the background, now i decided

to Register here.

My Name is Thomas, i am a German guy living in France, near Auxerre.

Last year i have built  a 145 Theremin which was my first diy theremin.

At the moment i am building a slightly modified Etherwave with Coilcraft slot 7 inductors.

After this Project i am planing to build a Keppinger or an other Tube Theremin.

I love Tubes and building tube amps, so a tube Theremin is a must for me.

 

Greetings from France,

Tom

 

 

Posted: 11/13/2017 8:12:55 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

Greetings Tom!

Sounds like you know what you're doing!  

How are you handling the issue of tuning the pitch side of your modified Etherwave?  I haven't tried this, but maybe add a small variable C to the antenna?  I also suggest you decouple the fixed and variable pitch oscillators (pre-mixer buffers, something I have tried!).  You can always easily add coupling later if you want it.

Posted: 11/14/2017 6:46:06 PM
JPascal

From: Berlin Germany

Joined: 4/27/2016

A good decision. Welcome. Greetings from Germany to France. What are you doing with your built theremins?

Posted: 11/14/2017 7:02:14 PM
mpampouras

From: Epalinges, Switzerland

Joined: 3/15/2005

Welcome to TW!

Posted: 11/18/2017 3:33:40 PM
Oilspill

From: France

Joined: 11/13/2017

@ dewster:

i added jfet buffers which are supposed to de the ESPE01 buffers. The fets are in smd at the copper side of the board. At the moment i can´t do the woodwork for the cabinet because i have a tendonitis and have to save my arm. The board is finished but not tested yet.

[img]http://up.picr.de/30982195qn.jpg[/img]

i hope the Picture upload will work....

@JPascal:

IO offered the 145 Theremin to a Friend which is musician. The EW which i am building is also for a friend. The next one will stay here i hope :-))

Posted: 11/18/2017 3:35:05 PM
Oilspill

From: France

Joined: 11/13/2017

EW_01

Posted: 11/18/2017 5:38:33 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"i added jfet buffers which are supposed to de the ESPE01 buffers." - Oilspill

Good!  

I like your PWB layout, though I would have wired the EQ chokes to better reject RF.  

A wooden cabinet isn't the best choice for the EW because wood is somewhat conductive and the EW tuning goes to hell when you take the top off (to tune it!).  So either provide a small adjustable antenna C pad, or drill some holes in the cabinet to access the inductors with the top on.

Posted: 12/17/2017 1:13:49 PM
ILYA

From: Theremin Motherland

Joined: 11/13/2005

"I love Tubes and building tube amps, so a tube Theremin is a must for me." -- Oilspill

Welcome to TW Tom!

Recently I was surprised to learn that oscillators in Simonov & Shivanov's theremin are built around so called "transitron oscillator" circuit. As stated, this topology has 10 times better stability than conventional tube oscillators. Perhaps, after the New year, I'll play with it. Would you like to try it too?

 

Theory (in Russian): Kublanovsky, Y.S. "Tranzitronnyi generator". Moscow-Leningrad, 1961.

[Edit] Found another paper in English -- Cledo Brunetti "The Transitron oscillator".

 

Posted: 12/17/2017 1:58:13 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

ILYA, I believe the TVox Tour uses a FET based negative resistance oscillator.

Posted: 12/17/2017 2:08:43 PM
ILYA

From: Theremin Motherland

Joined: 11/13/2005

that is a religion question. The warm sounding tubes! laughing

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