Here are a couple of vacuum tube based theremin projects:
http://home.att.net/~theremin1/126/126.htm
http://www.dogstar.dantimax.dk/theremin/bamtrat.htm
tung
Here are a couple of vacuum tube based theremin projects:
http://home.att.net/~theremin1/126/126.htm
http://www.dogstar.dantimax.dk/theremin/bamtrat.htm
tung