The AX1250 microphone preamplifier features 4 channels with gain from -12dB to +66dB, switched in 6dB increments with a trim of +/-6dB for each increment, independent LED metering on each channel, phantom power and a bypassable insert per channel.

A 2-channel VU meter built from a few spare parts.

It has nice big Kyoritsu meters and separate calibration controls on the front panel to allow simple alignment. You could use whatever VU meters you have available.

XLR in and out jacks for each channel on the back allow it to be inserted in line with the bus to the monitor switch.

A stereo balanced input mono balance check monitor.

Uses a 5" driver and has balanced stereo summing module, power amplifier and power supply on a single chassis plate as a complete solution.

XLR inputs for the stereo line signals and IEC mains input for power.

A range of general-purpose power supply modules used in many of the projects.

Single rail, dual rail and triple rail supplies are presented here using linear regulation, making them useful for audio projects.

An audio selector unit for two balanced inputs and four balanced outputs.

It features a trim control for each output and an attenuator from 0dB to -10dB in 2dB steps.

A 4 channel power sequencer to allow sequenced power up and power down of equipment with a 1.5 second gap between each.

Useful for powering up and down audio equipment in the right order to prevent thumps.

A modular balanced stereo line mixer with headphone module.

This simple balanced stereo line mixer was designed for use in the studio with external sources such as CD and DVD players, synths, i-devices etc that were played back on the monitors but not going through the DAW.

The modular approach consists of a stereo input module, stereo output module, headphone amplifier module and metering. The modules may be used independently if desired, with the headphone amplifier module being a high quality stereo headphone amplifier.

The audio bypass module provides relay-switched audio bypass functionality between the balanced input and output and the XLR FX in/out chain. Used in a variety of situations where simple true bypass functionality is required.

The audio changeover module can be inserted into a bypass module chain to provide either L/R channel changeover, or polarity reverse on the balanced signals.

A balanced 2-channel input is summed and output as a balanced mono output.

This can be used to feed a mono reference monitor to check for mono compatibility of audio mixes.