We found this circuit in an 80's manual. The same configuration can be adapted to make use of modern operational amplifiers. The power supply is symmetrical.
Two potentiometers mounted at right angles, so that they can be operated by a lever, form a very...
This circuit is from a 2005 Linear Technology manual. The circuit uses an LT6700-3 and has an...
This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response...