The Lower Chassis of a Theremin

Video Transcript

"On behalf of ExpertVillage.com my name is Mark, and we’re going to talk about the Theremin lower chassis of this particular unit. What we have here like I mentioned earlier is something very similar to a guitar amplifier. Our signal is generated by the upper chassis oscillators and after it leaves the volume control loop circuit, it goes into this jack and it feeds initially into the middle tube. It’s a 6SN7, its two stages of pre-amplification; the second stage is a phase splitter that drives the push-pull 6V6 output tubes. The rectifier for the high voltage is a 5Y3; the secondary high voltage supply is clamped by the VR150 or OD3 tube. They’re very beautiful, they glow a bright purple when they’re activated. The output of this chassis is 10 watts into an A dome speaker, there’s also an external preamp jack so you can run this into other equipment, effects pedals, reverbs and so forth. And then the other jack is an external mute. If you have a contact closure for your stage manager, whoever wants to quiet the Theremin down, they can do that externally. "