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This is a modification set for the Randall RM4* preamp. The modification enables the use of dual channel modules in Randall single channel MTS amplifiers. The range of features include channel selecting, storing and MIDI switching via program change messages for up to four single or dual channel modules. 

The set consists of a PCB, cables and additional accessories. Tools like screwdrivers are not contained. The set comes with an operation manual and detailed step by step installation instructions. Each work step is illustrated by a picture to guide you through the wole conversion procedure. The installation guide will be provided as a pdf-file after the purchase.

The MIDI-board is preprogrammed to receive commands on all MIDI-channels from 1-16 (omni mode). This configuration meets the needs of most players. If you want the amplifier to receive MIDI-messages on a different channel the programming will be changed according to the channel chosen from the drop down menu. The desired MIDI channel will be preprogrammed and can`t be changed afterwards.


Once the amp is opened up to be modified it is highly recommended to also add a manual cathode-bypass-switch to adjust the amount of low frequencies that pass through the first gain stage inside the amp. It helps to keep the sound tight when using high gain modules. The effect of the switch can be heard in the RM100-demo-video.

The current version of the "Herbert" module produced by Synergy is neither compatible with Randall- nor Egnater MTS amps.

Disclaimer: There are high voltages inside a tube amplifier, even when it is switched off. The modification requires soldering skills (three solder joints) and must only be done by a trained electrician! Don´t risk physical injuries or a damaged amplifier. Better let your local amp tech perform the modification.

* This product is neither related nor made by the Randall brand or its parent group