GM-70: Description

Tags: gm-70
- The Roland GM-70 GR To MIDI Converter was introduced to the guitar market in
1987. The GM-70 was one of the most significant technological leap found in any
of the seven generations of Roland Guitar Synthesizer products. This was the
first product to really give the guitar player the power and ability to use
MIDI as a tool of expression. Even now, the GM-70 is still a very usable
machine years after its introduction.

- Let’s look at why this unit is so innovative. The GM-70 was the first Roland
guitar converter that did not have any sounds of it’s own. Instead, it is
designed to function as a guitar to MIDI converter that can efficiently
transmit MIDI data to other MIDI devices. The GM-70 can also be used to control
the slew of rack mounted MIDI guitar effects processors that have saturated the
market in the last five years. The GM-70 works with the GK-1 which was the
first hex pickup that could be mounted directly on a standard guitar. It also
works well with any G series guitar.

- The MIDI Out of the GM-70 is fast and accurate. There are 128 total patch
configurations which are programmed to transmit a significant collection of
MIDI messages. Each patch is broken down into four individual "Branches." A
branch includes a significant collection of MIDI parameters. For openers, each
branch can be assigned to any MIDI channel and it can be set in Poly mode: all
six strings on one MIDI channel, or Mono mode: each string on its own separate
MIDI channel. Mono mode tracks much better than Poly mode because each string
has its own independent bend messages that are transmitted to the responding
synthesizers. Each of the four branches can also have it’s bend range set + or
- 36 half steps which allows maximum flexibility with a collection of
responding synthesizers. Each of the four branches can also have a separate
velocity curve set to it and it can transmit a MIDI volume message to the
synthesizer that it is assigned to. Within the individual string edits per
branch, each string can be turned on or off, have an individual transposition
set to it and, individual program change messages can be sent out per string,
per MIDI channel. Remember all of these edit parameters are available for each
branch. There are four branches in every patch and there are 128 patches in the

- The final innovative MIDI controller function that is featured in the GM-70
is the ability to transmit any MIDI continuous controller message from a huge
collection of controller knobs, switches and foot pedals. No less than eleven
different controllers can be assigned to any type of MIDI controller message
including: pressure, bend, modulation, volume, pan, hold, sostenuto. octave up
etc.. The GM-70 was also the first GR product that worked with the FC-100 Foot
Control Pedal. The FC-100 uses it’s own type of cable connector that transmits
program change messages from numbered foot pedals. It also transmits controller
messages from a controller pedal and an optional expression volume pedal. The
FC-100 is even phantom powered by the GM-70, so it does not need batteries or a
power supply.