Retro Mechanical Labs GPI Guitar Pedal Interface, Fallout Black
Retro Mechanical Labs

Retro Mechanical Labs GPI Guitar Pedal Interface, Fallout Black

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Regular price $89.00
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The GPI is designed to bridge guitar pedal world with modular synth world. An 8HP eurorack unit with two attenuators for sending a reduced signal to guitar pedals for better dynamic response and two pre-amps that boost that lower volume signal (from guitar pedal) back to eurorack levels. Each pre-amp splits the output signal into two patchable outs for creative routing options into other modules.

  • 2 units per module allowing for use with stereo pedals.
  • Use the pre-amps to boost other low level signals like line level gear. Outboard synths and drum machines.
  • Use the attenuators to reduce control voltages being sent from other modules
  • Plug your guitar right in to the GPI using 1/4 to 1/8 cables
  • LEDs flash in response to the signal being boosted by the pre-amps. A good indicator on how hard your driving the signal.
  • Very low power consumption.

There are many “Send and Return” modules available, all mono. With this one I wanted to make something available that could handle stereo pedals (or line level gear) without having to buy multiple units. Along the way I decided that having 1/4″ cables hanging off the eurorack seemed bulky and cumbersome so I went with 1/8 (3.5mm) jacks.

After building the first prototype I quickly found that just using the pre-amp worked great for boosting the Buchla audio level up to normal levels compared to my DPO and Lifeforms. Routing my Moog though the attenuation and into the pre-amp worked like a charm. Having this simple but versatile tool in my rack has definitely been enjoyable. Not only can I now use all those old guitar pedals with my system, but external keyboards I hadn’t considered are now an option.


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