This 7-tube circuit was obtained from an American publication in 1947. The circuit has a push-pull output with a source using a transformer.
This circuit works only with carbon microphones, due its low impedance. The speaker should be good or...
This preamplifier is intended for the use with magnetic pick-ups. Power supply must have voltages...
We found this amplifier in a publication of 1990, but it can be mounted today with some exchanged...