312 Module PCBs

This set of PCBs allows you to build a vintage 312-type microphone preamplifier.
Here are the key features of our 312 module:

• Very short signal path. Switching via relays.
• Active FET DI circuit.
• Switchable -20 dB input pad.
• Switchable low impedance input.
• Switchable additional output transformer winding for increased output level.
• Optional servo circuit mod.
• Optional 3124+ type mod (caps on the output of the op-amp).
• Includes our take on the 2520 discrete op-amp.

These PCBs are intended to be used in our 4-channel frame system. 312 module takes up one slot space and needs +/-22V or higher (unregulated) for proper operation. We suggest installing no more than two modules if using internal PSU.