The Quartet is a modern class A tube design which includes:
The tube Mic/DI Preamp from the MDP-1
The tube Opto-Compressor from the OCL-2 using a proprietary optoelectronic cell
A new three band tube EQ with HI and LO shelving and peaking MID band
A new de-esser design using opto-inductive filtering and a highly selective detector
The Mic/DI, EQ and Compressor/De-Esser can be patched out and used independently.
Transformerless or transformer-balanced main output
Gold-plated switch contacts, I/O connectors and tube sockets
Polypropylene caps and metal film resistors (pairs matched to 0.1%)
Fully regulated high voltage (300V) and filament and bipolar power supplies with soft-start warm-up and output muting
Custom toroidal power transformer with shield for minimum hum
120V or 240V ac voltage switch on the rear panel.