User`s manual

1.1. Kit Contents
The kit contains everything you need to bring remote gain control to three eight-channel preamps:
 Remote Gain Controller box, model RGC-24A-M
 Power supply 12V, 1A
 24 high-grade analog optocouplers, individually selected to match to +/-5% resistance value
 3 pcs. D-SUB cable, 9 pin, 1:1 male-female (for connecting the preamps to the controller)
 3 pcs D-SUB connectors, 9 pin, male, for preamp mounting
 3 pcs. flat ribbon cable, 9 pin, for connecting optocouplers to the D-SUB
 Insulated copper wire, for connecting the common anode of the couplers together
 Green LED for testing purposes
 Cable tie for strain relief
 This manual
2. INTRODUCTION
2.1. Supported Microphone Preamps
Currently, preamps with 5k to 50k logarithmic potentiometers are supported. Typical models using these values
are:
 Behringer ADA8000
 Focusrite OctoPre MkII
 Focusrite OctoPre Dynamics
 ART TubeOpto 8
 Presonus Digimax D8
 Mackie Onyx 800R
 RME Octamic
 RME Octamic II
 all other preamps with pots in 2-pin configuration – contact us if you are unsure about your model.
Remote switching of digital functions (e.g. pad or phantom power) via reed relays is also supported. The required
relays are not included, please contact us for model recommendations.
2.2. Features
The Microphone Preamp Remoting Kit adds remote gain control capability to your existing preamps, enabling
you to position your microphone preamps on stage. Gain control is achieved by paralleling the existing
potentiometers with high-class, analog optocouplers driven by an external control box (the Remote Gain
Controller). When active, these couplers take over the function of the mechanical potentiometers for gain
adjustment. The individual gain levels can be set using standard MIDI commands.
The system has many advantages over other solutions:
 Allows to re-use existing preamps
 One RGC-24A-M controls up to 24 channels (e.g. three eight-channels preamps).
 Can be extended up to four controllers (96 channels)
 Sound quality and characteristics of your preamps remain unchanged
 Very simple installation, needs only two solder points per channel within the preamp
 Non-intrusive mod, can easily be undone
 No further modification of the original circuit
 Preset control curves (gain vs. resistance) for different preamps
 Automatically remembers last gain settings on power up
 Control curves can be altered by the user for perfect matching to any preamp type
5