This RIAA equalizer preamp was found in a 1990s schematic. The transistors are an old version of the BC549 that can be used as a replacement. Signal input and output cable must be shielded.
Suggested by Fairchild in a 1980s publication, this multiplier uses operational amplifiers from that...
We found this circuit in an English publication from 1980. It provides a logical output signal when...
This unusual amplifier configuration is from 1986. The circuit has a high resting current given the...