calling all Keppinger tube theremin builders

Posted: 1/18/2010 4:14:26 PM

From: Anacortes, Washington

Joined: 5/5/2009

ROSS HERE: Building a Keppinger Theremin: I was told the C11 cap is a compression type 20-150pF
of close to it.
Also told to get better base notes: connect .1 cap 100v. between pitch antenna and OSC.?
" The capacitor between the oscillator and antenna coil is 0.1 mfd 100vdc. Anything but Z5U ceramic; a polyesterene or polypropolene is best.
C11 - The capacitor is a compression type tuning capacitor. I think the ones were around 20pf - 150pf, but anything close should be fine."
Posted: 1/18/2010 5:36:22 PM

From: Anacortes, Washington

Joined: 5/5/2009

All three 6J5 tubes are oscillators; one for the volume oscillator circuit, and the two for the pitch circuit which 'beat against each other', and the difference in frequencies being the pitch
you hear.
The pitch antenna coil connects to the pitch antenna at the top, and one end of the .1 mfd capacitor. The other end of the .1 mfd capacitor
connects to the top (100 turns) end of the pitch oscillator coil on the outside of the chassis (as opposed to the pitch oscillator coil in
the middle).
Posted: 1/18/2010 9:32:37 PM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

Ross - Your information does not agree with the information we have. Where did you get it?

There are schematics and a component list on the TW schematics page. (Note: Large pitch and volume coils should be listed as 3.10" diameter.)
Posted: 1/18/2010 10:30:37 PM

From: Anacortes, Washington

Joined: 5/5/2009

oh well, I am new to beginning to build one myself.. just posting Mark's comments to me as I get them. I may be able to restore Predicta Chassis' to work, but I can't even WIND up a METAL DUCK let alone a COIL! If I build it and all it does is SCARE dogs away, I'll be doing real good! LOL
Posted: 5/26/2010 10:15:57 PM

From: Hillsborough, NC (USA)

Joined: 2/13/2005

Big thanks to Jeff S for an updated components list for the Keppinger theremin!! I've uploaded his revised list to the schematics page.
Posted: 5/27/2010 10:29:11 AM

From: Brooklyn,NY

Joined: 12/1/2009

Besides the exclusion of R31 &32 are there any other changes to the revised parts list? i was just looking it over and that was all I noticed.

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