Looking for schematics for the Big Briar 91A mod

Posted: 1/26/2014 11:08:30 PM
Theradamin

Joined: 1/26/2014

Hi, I recently acquired a 91A theremin which I am quite happy with, but would very much

like to get the mod done on voice #2, which is supposed to allow for a tone close to that

of Clara Rockmore's theremin.

 

I was disappointed to find out that this Bob Moog's schematic is not readily available. I have a

good technician waiting to do the job if I can locate one somewhere. Does anyone have

or know of someone who might have it. Would much appreciate the help, thanks!

 

Adam

Montreal, Canada

Posted: 1/26/2014 11:15:47 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

Hi Adam,

this 91A mod was recently discussed on the Levnet mailing list and a Canadian 91A owner which has got this modification promised to send me high-res pictures from his audio circuit board, so that I could try to reverse-engineer it by comparing to my high-res pictures of an unmodified 91A board. But up to now I didn't yet receive the pics. As soon as I can advance on this subject, I'll post the news here.

Posted: 1/27/2014 4:58:06 AM
Theradamin

Joined: 1/26/2014

Merci!

 

Hi Adam,

this 91A mod was recently discussed on the Levnet mailing list and a Canadian 91A owner which has got this modification promised to send me high-res pictures from his audio circuit board, so that I could try to reverse-engineer it by comparing to my high-res pictures of an unmodified 91A board. But up to now I didn't yet receive the pics. As soon as I can advance on this subject, I'll post the news here.

Posted: 1/27/2014 12:28:40 PM
coalport

From: Canada

Joined: 8/1/2008

Thierry wrote: ".....a Canadian 91A owner which has got this modification promised to send me high-res pictures from his audio circuit board..."

 

Hmmmmmm.....I wonder who that could be?

 

Sorry guys, I have been rather busy lately and the whole thing just slipped my mind. I'll try to get around to it this week. 

 

The modification in question was supposed to emulate the sound of Clara Rockmore's instrument but I am sorry to say it doesn't even come close.

Posted: 1/27/2014 2:08:48 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

Sorry for my poor English grammar, it should read "... 91A owner who has ..."

Please accept my apologies!

Posted: 3/29/2015 7:18:38 PM
Theradamin

Joined: 1/26/2014

Hello coalport,Thierry, haven't checked in for a while, still very interested in this mod and the schematics. Any progress on this? Adam

 

Posted: 3/29/2015 11:50:07 PM
coalport

From: Canada

Joined: 8/1/2008

Hi Adam, when I purchased my 91A from Levnet founder Dave Ball, since he was living in Tennessee I had him ship the thing to Moog Music in Asheville N.C. so that the Rockmore sound modification could be made. The teks at Moog had quite a time trying to find Bob’s original specs. This was just a few months after Bob’s death in 2005. 

 

Although Bob promised to furnish SERIES 91 theremin owners with all the necessary diagrams and specifications so that repairs could be made to their instruments, this never happened. Now that Bob is gone, it will NEVER happen. 

 

 

I did take detailed pictures of my 91A circuit boards as I said I would, and I sent them to Thierry, but I do not know what he was able to deduce from them.

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