New! The KA-Electronics Monitor Controller, "Monco," is the latest addition to our transfer console line-up.

This is a bare PC board.

Monco has the following features:

• Two fully-balanced relay-selectable A/B inputs.
• Two fully-balanced Monitor outputs, Main and Alternate, with mute relays and power-on/power-OK delay.
• Fully-balanced Auxiliary output for A/D or Meter drive. Two jumper or switch-selectable gains (typ. 0 or -10 dB) or ±5.5 dB gain trim using an external 10KΩ control. (If using a stepped switch, shorting, make-before-break, contacts are required. Most Elma 15° 24 position switches are shorting.)
• Monitor Attenuator Connector for external 2KΩ-10KΩ stepped switch or potentiometer.
• Jumper or switch selectable source for the Aux Output. (Input A for driving an A/D input or follow monitor pre-attenuator for metering.) 
• Stereo, Mono and Difference monitoring. Can be toggled between any two modes by a single button press.
• Monitor Dim. (-20 dB standard.)
• Separate isolated +24V relay supply. On-board 7824 regulator or external +24V supply.
• ±15V Power OK LED output.

Relay controls with LED outputs

• Input B
• Mute L; Mute R
• Mono (L+R)/2; Difference (L-R)
• Monitor Dim
• Monitor Cut
• Alternate Monitor
• Each relay control has an on-board 2K21Ω current limiting resistor for approximately a 10 mA LED current. Power OK LED resistor is 10KΩ.

Mechanical and Power Specifications

• Board Size: 6.3" x 3.3" Mounting holes: M3 on a 6" x 3" pattern. Assembled height: Approximately 1" not including stand-offs.
• Power Requirements: ±15 to ±18V (max) approximately 65 mA (no signal current). +24V at 20 mA per relay/LED 200 mA maximum. Up to +36V using on-board regulator.

Audio Specifications

• Inputs: THAT1246. Input Impedance 24KΩ differential, 18KΩ common mode. Maximum input level +27 dBu.
• Outputs: THAT1646. Output impedance 50Ω nominal. Maximum output level +27 dBu.
• Monitor Level Control: Input Impedance at the Wiper Connection 100KΩ. Recommended control value is 2KΩ to 10KΩ. Wiper AC-coupled -3 dB 0.7 Hz.

Monitor Outputs

• Gain: +6 dB max; Dim -20 dB. Noise: -95 dBu at 0 dB gain, 10KΩ control at -6 dB attenuation. -96 dBu at maximum gain or full attenuation. Dynamic Range 122 dB.
• Distortion: Output level +20 dBu into 10KΩ load. 1 kHz THD 0.00012%, primarily HD3.
• Note: Monitor Outputs are relay-protected and will not operate until the differential supply voltage has stabilized to >27V (±13.5V) to provide turn-on/turn-off delay.

Auxiliary Output 

• Gain: 0 dB nominal. Noise: -98 dBu, -100 dBu A-weighted. Dynamic range 125 dB.
• Distortion: Output level +20 dBu into 10KΩ load. 1 kHz THD 0.0001%, primarily HD3.
  

Note: Noise measurements are for a 20-20 kHz bandwidth and are unweighted unless specified. Maximum level specifications are for ±15V supplies.

Additional audio specifications and performance as they become available: Please refer to the forum. 

To learn more about "Monco," the KA-Electronics Monitor Controller, visit the Pro Audio Design Forum construction thread.

The KA-Electronics Monitor Controller is sold as either a bare PC board, a "kit" (including  2 THAT1240, 4 THAT1246, 4 THAT1646 ICs, 2 OPA2134 and an NE5532), and the assembled and fully-tested module shown here.

A Mouser Electronics Project Manager bill-of-materials is available for DIY builds.