Converting Old Amp

Posted: 9/25/2016 4:44:56 AM
new2theromoo

Joined: 9/25/2016

i have a guitar amp i dont use anymore because the input is broken but i was thinking of trying to recycle it into a theremin. im not really sure what ill need though, i cant seem to find anyone who has done it before. im hoping its as simple as getting a couple oscillators and antennas and i can call it a day but idk if i need to worry about voltages or amperage because the idea is to just plug it into the wall and start playing. if anyone has done this or has any idea how to go about it, please let me know

Posted: 9/25/2016 2:47:08 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

TW needs conversations and a little entertainment. wink

Every theremin needs a good amplifier to be part of the setup and being old makes it a nice complement. Guitarists do make good Thereminists.

A theremin is nothing more than coat hanger antennas, oscillators, mixer and an amplifier. Then she has attitude that will kick the ass of most engineers. Always ask for a sound sample to validate any designers claims.

Can you tell if your amp uses transistors or vacuum tubes? 

Are you in the States? The time on your post says the western half of the USA.

Christopher

Posted: 9/26/2016 10:09:39 PM
Fat Bob

From: Florida

Joined: 9/3/2016

You'd need to access the transformer to make a lower voltage power supply (a schematic would be good to have).

Then you could build something like this inside it;

Another one

Posted: 9/26/2016 10:35:26 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

Wow, 20MHz pitch side and 15MHz volume side.  I don't think I've ever seen such a high frequency Theremin circuit.

Posted: 9/27/2016 11:05:44 PM
Fat Bob

From: Florida

Joined: 9/3/2016

Ya I like my Theremins at as high a frequency as possible to reduce the "Lag" HeHe Just kidding.

Having the schematic makes it a lot easier. Just run the +-20V into +-12V regulators, build the 

circuit and slap it into the case. Of course you will need to keep the coils away from the transformer.

I'm building the same circuit with a couple of tweaks.

I talk about the mods in this thread SBL1 Mixer

Here's a picture of it so far;

My EW

 

 You might want to read this thread before buying parts ; Coils for EW

Posted: 9/28/2016 2:10:06 AM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"Ya I like my Theremins at as high a frequency as possible to reduce the "Lag" HeHe Just kidding."  - Bob

It's not something I'm an authority on, but the higher the frequency the lower the absolute sensitivity (NOT musical sensitivity, which I believe is pretty much fixed if things are adjusted for maximum linearity) and this means stability (things like thermal noise and drift and such) becomes more of an issue.

Posted: 9/28/2016 5:08:28 PM
new2theromoo

Joined: 9/25/2016

"TW needs conversations and a little entertainment.  Every theremin needs a good amplifier to be part of the setup and being old makes it a nice complement. Guitarists do make good Thereminists. A theremin is nothing more than coat hanger antennas, oscillators, mixer and an amplifier. Then she has attitude that will kick the ass of most engineers. Always ask for a sound sample to validate any designers claims. Can you tell if your amp uses transistors or vacuum tubes?  Are you in the States? The time on your post says the western half of the USA. Christopher"

 Firstly, i am in the states, but east coast (i just stay up late). and the amp is transistor based. i found a schematic for an etherwave theremin i like Etherwave Schematic

 

i believe this is the schematic for my amp http://imgur.com/gallery/2wbJT

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