Since we did not have good experiences with commercial amps in terms of noise from the audio output and from fans, we aim for our own design.
We would like to have 4 inputs and 4 outputs, switchable between direct routing from in to out, and alternatively, a routing from stereo through two 2-way crossovers to 4 outputs. Volume control would also be necessary.
Additionally, USB audio input, AES67/Dante network audio input, parametric EQ and limiters would be useful. This is possible by processing audio through a combination of an SBC (e.g., Teensy 4.1) and a DSP board, or — if latency can be small — an SBC only.
We are basing on two Hypex NC502MP OEM amplifier modules, each complemented by a NC100HF OEM HF extension. This combination has 4 full-power and 2 low-power channels. The modules fit into an 19" 2U enclosure.
Connector pin numbering convention:
The numbering with Pin 1 starts at the edge with the red-colored cable, on the side of the connector "nose". Pin 2 is on the opposite side, that is, pins are running zig-zag across the connector.
Standby:
The amp is in standby mode until Pin 9 of the H-Bus connector ("PS Enable") is set to high level (i.e., connected with 5V over Pin 3 "VOUT,STANDBY")
Part list:
- Aluminum enclosure 19" 2U, more details .
- Hypex amp modules 2 x NC502MP + 2 x NC100HF
- 2 x Noctua 80mm PWM-controlled fans
- 4 x Fan protection grille 80mm
- 4 x XLR combo connectors, e.g., Neutrik NCJ6
- 2 x 4-pole, 2 x 2-pole Speakon connectors, e.g., Neutrik NL4 MPXX
- Power connector (e.g., Neutrik NAC3 MPXXA) and mains switch
- 2 x passive coolers
- DSP board, volume control, touch screen for preset selection and monitoring
Alternative:
Instead of 4+2 channels, also 4+4 channels is possible:
- 4 x Mono amplifier module NC500MP, (146 x 105 x 42mm)
- 4 x HF amplifier module NC100HF, (85 x 39 x 27mm)
The NC500MP deliver only 270W RMS per channel into 8Ω, though.
