Ray Lubow invented the oil can echo, sold under various brands, Tel Ray, Dimension IV, Morley, Vox, Standell, and Fender Echo-Reverb I, II, and III, all useing the same “oil can” with a rotating disk inside, a couple spoonfuls of oil, and two or three rubber- like play “heads”. A third “erase” head is grounded to the case to keep the echos from going too long, without it you can get about 18 repeats!
The combination of the special disk surface and the special oil makes it a capacitive storage device.
I have an oil can unit with no electronics.
I have tried using pre-amps, small power amps, various input and output transformers, and can get lots of echos from it, but the signal to noise ratio is about 1/1, actually more noise than signal.
The oil can echos are normally noisy, but not like that. I do have fresh oil of the special kind that makes the device work in it.
I admit I can’t tell from the schematic what it does, can anybody tell me what it’s doing?
The tubes are 12AX7, the schematic says 1/2 12AX7.