Channel Tester I built for fault finding on the Neve 88R and VXS at Angel Recording Studios back in 2018 with the help of Alex Watson.

The tester provides power and controllable global bus logic signals ordinarily supplied via the centre section. The brains of the unit is a raspberry pi with touch screen display.

A logic interface logic board converts the +3.3V logic of the pi into -15V - 0V logic of the neve consoles. This is used for the global bus controls, and for addressing the Neve channel’s on-board recall multiplex via shift registers.

An analogue multiplex board handles all of the audio routing, controlled by the Raspberry Pi. This allows for the test signal to be routed to any input, and any output of the channel to be monitored and tested.

The test window allows for the selection of channel output, and provides a voltage reading of the test signal and output signal for quick comparison.

The recall window page gives a continuously updated display of the channel controls current position, just as you would find on the console. Pressing on a knob or button in this window brings up a voltage display of the reading on the ADC from that button’s recall multiplex address bank. On the Neve, this voltage is a binary encoded number, allowing you figure out if you have the correct voltage for the combination of switches engaged in that bank of 4.