The MXR RR104 Randy Rhoads Distortion+ is a distortion pedal built as a signature version of the classic MXR Distortion +. Jim Dunlop's manual says the circuit was "painstakingly matched to the legend's own MXR Distortion+ to recreate the same raw, overdriven tones heard on his most beloved hits"12. Like the pedal it is based on, it keeps the layout simple: two knobs and a footswitch.
The controls
The RR104 follows the Distortion+ format of two knobs and a footswitch, so there is very little to learn. The manual describes each control as follows1:
| Control | What it does |
|---|---|
| OUTPUT knob | Controls overall volume of effect |
| DISTORTION knob | Controls amount of distortion |
| FOOTSWITCH | Toggles effect on/bypass (red LED indicates on) |
For a starting point, the manual's advice is simple: "Start with all controls at 12 o'clock." From there, turn up the DISTORTION knob for more grit and use the OUTPUT knob to set your level1.
Power: 9V, 11 mA
The RR104 runs on DC 9 volts and draws 11 mA, which any standard pedalboard supply can handle. It can also run from a single 9-volt battery; the manual notes you remove the bottom plate to install it1.
The manual specifies a 9-volt AC adapter such as the Dunlop ECB003/ECB003EU, or an MXR Brick Series power supply1.
Connections are the usual pedal setup: run a cable from your guitar to the Distortion+'s INPUT jack, then run another cable from the Distortion+'s OUTPUT jack to your amplifier1.
The RR104C special edition
Alongside the RR104, MXR offers the RR104C Randy Rhoads Special Edition Distortion+, a special edition version of the same pedal. The two share the same core design and specifications2:
| RR104 | RR104C Special Edition | |
|---|---|---|
| Type | Distortion pedal | Distortion pedal |
| Controls | OUTPUT, DISTORTION, footswitch | OUTPUT, DISTORTION, footswitch |
| Power | DC 9 volts | DC 9 volts |
| Adapter | Dunlop ECB003/ECB003EU or MXR Brick Series | Dunlop ECB003/ECB003EU or MXR Brick Series |
| Output impedance note | Output control at mid position | Output control at mid position |
Both manuals describe the circuit the same way: matched to Randy Rhoads' own MXR Distortion+ to recreate the same raw, overdriven tones heard on his most beloved hits12. MXR describes the special edition as "painstakingly matched to the legend's own MXR Distortion+," the same wording used for the standard MXR Randy Rhoads Distortion+2.
If you want to hear where the Distortion+ circuit sits among MXR's other dirt pedals, from the M104 Distortion+ to the M75 Super Badass Distortion, the Distortion Pedals page lays out the range.
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Questions
Does the MXR RR104 Randy Rhoads Distortion+ take a battery?
Yes. According to Jim Dunlop's manual, the RR104 is powered by one 9-volt battery, and you remove the bottom plate to install it. It can also run from a 9-volt DC adapter such as the Dunlop ECB003/ECB003EU or an MXR Brick Series power supply, drawing 11 mA.
Is the MXR RR104 true bypass?
Yes. The manual lists the bypass type as True Hardwire, and the footswitch toggles the effect on and off, with a red LED showing when the effect is on.
How is the RR104 different from the standard MXR Distortion+?
The RR104 is a signature version of the Distortion+ circuit: Jim Dunlop says it was painstakingly matched to Randy Rhoads' own MXR Distortion+ to recreate the same raw, overdriven tones heard on his most beloved hits. The controls and layout follow the same two-knob format as the standard pedal.
Where do I start with the knobs on the RR104?
The manual's recommended starting point is to set all controls at 12 o'clock, then adjust the DISTORTION knob for the amount of distortion and the OUTPUT knob for the overall volume of the effect.
What is the difference between the RR104 and the RR104C?
The RR104C is the Randy Rhoads Special Edition Distortion+. Both are distortion pedals matched to Rhoads' own Distortion+, both run on DC 9 volts with the same adapter options, and both share the same two-knob control layout. The special edition carries the same specifications, including output impedance measured with the output control at mid position.
What power supply does the RR104 need?
It needs a DC 9 volt supply: a 9-volt AC adapter such as the Dunlop ECB003/ECB003EU, or an MXR Brick Series power supply. It draws 11 mA and can also run from a single 9-volt battery.
Sources (2)
- RR104.pdf, Jim Dunlop, 2024
- RR104C.pdf, Jim Dunlop (jimdunlop.com), 2025
