The Stereo DCServo-Relay is a combined servo unit for control of an amplifier feedback loop, and a relay disconnect circuit primarily intended for disconnecting the speaker output of a power amplifier the moment output DC cannot be corrected by the servo circuit. It will re-set on removal of the DC component.
The stereo servo unit features a socketed high gain (dual) op-amp in a regular integrator/filter configuration producing a control signal to the inverting (feedback) input. In addition the chip will drive the relay to switch off output from the signal wire it is sensing.
The relays are rated for a full 10A of AC or DC current so can be applied to speaker outputs from a pair of amplifier channels or used for preamp or other devices. The design allows for optional tertiary output filtering when the amplifier supply is used.
The Stereo DCServo-Relay is powered from +/-12V DC or 15Vac CT at 50mA. Other supply options are possible, including amplifier supply powering and plugpack/wallwart.