"Little-known vintage boost used by Jimmy Page"



The MOAB boost rack effect module compares to the Univox UniDrive UD-50, an early boost used by Jimmy Page.  It is a huge boost that goes from clean-ish to really dirty, especially good for pushing the front end of a tube amp.  In 1971, it was advertised as producing "an electronic cello effect".  Whether or not you need an electronic cello in your band, this is a great boost that can wipe out the first few rows of your audience when you crank it up.  Its big output and early release lead us to call it the "Mother Of All Boosts".



The GT MOAB compares to the Univox UniDrive UD-50, a vintage boost pedal.  Not much information is readily available about the Univox Unidrive UD-50.  About all we've found is that it was available in the early to mid-70's.  It looked like a volume or wah pedal, as it was a big pedal with a large rocker foot control.  Jimmy Page and probably others used them.  They have a large output that can get dirty itself or drive an amp into distortion and fuzz.  It was probably often mistaken for a volume pedal.  No effect will give you "Jimmy Page in a box".  But the GT MOAB can give you a great starting point if you have a tube amp and nimble fingers.  The March 13, 1971 issue of Melody Maker shows Jimmy with the UniDrive, as well as his Les Paul and violin bow.  They note that the pedal was designed to produce an "electronic cello effect".

The circuit has 3 silicon transistor stages, making it a bit like a Colorsound Power Booster with a feedback loop.  But the tone stacks and other parts of those two circuits are different, giving them unique sounds.  It used 2SC859 transistors, a little-known and uber-rare transistor that is virtually impossible to find, except for counterfeits.  Luckily, that transistor was nothing special in any way.  A variety of good silicon transistors sound great in the circuit.

The original UD-50 had a Gain control, as well as a knob to control the range of the pedal and volume, a rather wonky design.  Since there is no foot rocker for our module, the range and volume control are combined into a single Volume control, along with a Gain control.  This arrangement is more intuitive and works better than the original control setup, providing the same range of tones.



  • MOAB - Compares to Univox UniDrive UD-50 



No buffers



  • Tone Control - This is a simple input Hi/Lo Tone control, like that found on many Fuzz Face variants, including our Woodstock module.
  • Feedback Trimmer - The feedback portion of the circuit is not adjustable in the original pedal.  This option gives you a trim pot on the board to adjust the feedback.  It is intended to be a "set it once and leave it alone" option that will allow you to tweak the sound of the module.
  • Feedback Control - This is the same as the Feedback Trimmer option, but makes it an external knob on the front panel instead of a trimmer on the board.  Probably neither option is hugely necessary, but it you like to tweak your tone, then the external control is certainly more convenient than a trimmer.


Front Panel

  • Gain - Volume and distortion increase with the Boost Level
  • Level
  • (optional) Tone
  • (optional) Feedback


Rear Panel

  • Audio In
  • Audio Out
  • On/Off Footswitch
  • On/Off Override
  • DC Power
  • DC Power LED


Module Width

  • 1.5"
  • 2" left wing available
  • 1.5" right wing available


Power Consumption (aprox)

10 - 15mA


Base Configurations

Part # Description List Price
MOD-MOAB MOAB module $189



Part # Description List Price
MOPT-MOAB-TONE Tone Control Option $19
MOPT-MOAB-FBTR Feedback Trimmer Option $0
MOPT-MOAB-FDBK External Feedback Control Option $19



Part # Description List Price
MPT-MOAB-CA Replacement pot, switch, jack, LED cable assembly $19
MPT-MOAB-KNB Replacement control knob $2
MPT-MOAB-PB Replacement power board $29
MPT-MOAB-SB Replacement switching board $29