6-TUBE THEREMIN PC BOARD COMPLETE

This Ebay listing looks interesting.  Can anyone comment on it?

http://www.ebay.com/itm/351553051543?_trksid=p2055119.m1438.l2648&ssPageName=STRK%3AMEBIDX%3AIT

looks pretty close to a art harrison theremin?

http://theremin.us/126/126revised.html#Parts

Dear oldtemecula,                                                                                                                                 

I'm sorry but I do not have a sound file for this board. A new model will be out in few weeks and I will be sure to put up a sound file with it.                                                                                                                                                            

This version offers both volume and pitch. The new model will have the standard volume and pitch and an optional divider accessory which is foot-operated (a foot switch like a stomp box has but momentary and variable as to be able to adjust the depth). The divider drops the pitch by one octave and allows you to mix it in with the original creating a 2-note chord. The divider will be sold separately but is designed to work with the new board.                          

Keep an eye on my auctions for the new model which should be available in assembled, kit and bare PCB forms in about 3 weeks. The board is larger (about 11 1/2" x 8 1/2") because it uses different tubes and looks much more "tubey"....                                            

Wolfman         

Does this model come with tuning instructions or recommendations for antenna thickness and length?  Schematic? 

I fear for the coil located near transformer. If that coil has a ferrite core, it may be modulated by the magnetic field 50/60 Hz from the transformer.

"I fear for the coil located near transformer. If that coil has a ferrite core, it may be modulated by the magnetic field 50/60 Hz from the transformer."  - ILYA

Let's stick a big honkering AC transformer one inch from the EQ coil, what could possibly go wrong?

Text on the PWB says:

   "Theremin in a Box!  ... and the Wolves like it!  Play Me and howl like a Wolf!"

The thirst for profit causes the manufacturers of transformers (Chinese in particular) to reduce the turns per volt ratio. The result is not  an increased heating only, but an increased external magnetic field too (caused by saturation of the core).

Acting on the ferrite coil, this field changes the effective permeability of ferrite 100/120 times per second (or 50/60  times per second in case of the additional magnetic offset -- closely located speakers, magnetized parts, geomagnetic field, etc.).

Finally, the inductance of ferrite coil is parasitically modulated as well as the frequency of RF oscillator.

The output audio becomes like this:

(taken from the EW detector, a power transformer was moved closely to the coil).