The Mu-Tron III is a classic envelope filter but like most vintage effects it is missing the amenities that professional guitarists demand from their rig. The modifications on this page are for the Mu-Tron that runs on two 9V batteries or a specialty 3-pin power supply.
Our Overhaul Mod includes converting the pedal to true bypass, installing a status LED, installing a sensitivity knob, and converting the pedal to run off of 9V DC.
A significant problem with the Mu-Tron III is the Gain control. It adjusts the volume of the pedal when bypassed, the volume when activated, and also controls how wide the filter opens. This can be problematic because it may be difficult to set the pedal’s bypassed volume to the same volume as if the pedal were never plugged in. This can lead to unintentionally overloading other devices in your signal chain. The true bypass mod allows the signal to go from the input jack to the output jack without any change in tone or volume.
The Sensitivity Knob controls how wide the envelope filter opens similar to the way the Gain knob works, but without adjusting the volume of the circuit. It strictly adjusts the sensitivity of the envelope detector circuit. This is useful if you find that you need to crank the Gain knob to get the filter to open wide enough but then the volume is just too loud and overloading your other pedals in the signal path.
The 9V Inverter Mod installs a voltage inversion circuit and a “Boss style” DC jack so you can run the pedal off of a standard 9V adapter or a 9V battery. It does this by replicating the -9V power that the second battery puts out. The rest of the circuitry– especially the audio path– is left 100% original and the pedal can be converted back to stock with minimal work if ever needed.
We also offer an optional add-on to replace the electrolytic capacitors with new ones of the same value. This is excellent preventative maintenance as these capacitors are beyond their rated lifespan and can fail as the electrolyte dries out.
Overhaul Mod………………………………………………………….. $135
Add Electrolytic Capacitor Replacement…………….…………………….. $30