This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response of 150 Hz to 40 kHz. The power supply must be symmetrical.
Information about the high voltage transformer and the detecting circuits was not given in this...
This simple circuit can make use of any general-purpose transistor. The power comes from the...
We found this timer circuit in a 1999 documentation. It triggers two relays sequentially, at...