Series 91A at ebay

Posted: 12/17/2009 8:41:00 PM
Thomas Grillo

From: Jackson Mississippi

Joined: 8/13/2006

Just saw this on ebay while poking around.
Posted: 12/20/2009 6:17:53 AM

From: Canada

Joined: 8/1/2008

I see the bidding was to start at $7,500.00! The auction ended on Friday with no bids at all. I think the seller was a bit optimistic.
Posted: 12/20/2009 9:01:30 AM

From: Colmar, France

Joined: 12/31/2007

If I remember well they were sold new for around 3500$. If one takes into account that they have nice housings on on side but that they aren't "real" theremins on the other side, I think that 2500$ would be a more realistic price.

Why aren't they "real" theremins? There were always rumors that the pitch antenna was used to attenuate a rf signal as a function of hand proximity. The resulting control voltage was intended to control directly an audio frequency generator. So there wouldn't be neither a second pitch oscillator nor a mixer stage.

I found this principle of operation fully confirmed when I had been asked to diagnose a Moog 91C with pitch range problems during the NodeFestival in Lausanne, Switzerland last weekend.

Finally I could help the owner by finding out that the main frequency determining capacitor of the pitch oscillator had lost some of his capacitance. I told him to buy 4 capacitors (1pF, 2.2pF, 4.7pF, 10pF) and to solder them one after the other in parallel to the existing capacitor until the pitch range would be within the normal specs.
Posted: 12/26/2009 10:05:32 PM

From: Richmond Hill, Georgia

Joined: 9/18/2005

This one looks rough. Why wasn't it taken better care of if it was a "one of a kind" unit. Scratched all to hell and back.....


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