Geo 1 transistor theremin.

[col]

Has anyone built this? I built it last night and then realised that there was no info on where to connect to an amplifier. Where do I take off the 'out'?  I used a 2N3906 in place of the BC307 as the data sheet says that it should be a replacement. I tried contacts on the board I used but just got crackle.
Col

[Paul Perry (Frostwave)]

If this http://www.geocities.com/SunsetStrip/Studio/2987/theremin.html is the one you are talking about, the sound is output via the transistor radio. You can eihter mic the radio speaker, or pick up electrically from across the speaker (shield to radio ground, active via a .1 uF cap to whichever side of the speaker is loudest).
Don't expect miracles.......!

[GFR]

Yes, don't expect miracles. You need an AM radio near it, and then you try tuning the radio dial until your hear a whistle plus lots of noise. As you wave your hand near the sensor the pitch of the whistle changes. Listen to the sound sample to get an idea.

Going slightly off topic, I just saw Paul's page on a dod Wha/Vol that uses the capacitance between the footpedal and a pcb to generate a control voltage. Similar principle as this "theremin".

[col]

Doh! If I'd read it properly I'd have seen that sentence. I must have read it 5 or 6 times and missed it.

Thanks

Colin

[Paul Perry (Frostwave)]

Going slightly off topic, I just saw Paul's page on a dod Wha/Vol that uses the capacitance between the footpedal and a pcb to generate a control voltage. Similar principle as this "theremin".

Hmmm..... it couldn't have been THIS Paul, I don't have a page! and i certainly can't remember hearing anything of this.. can we have a link? (i do forget stuff, but it would be an impressive effort to forget THAT!)

[GFR]

 

Sorry, it is ANOTHER Paul 

Paul Marossy:

http://www.diyguitarist.com/DIYStompboxes/FX-17.htm