The Deluge Bass Distortion is a bass distortion project from J. Michael Pedals, sold as a DIY kit through General Guitar Gadgets. General Guitar Gadgets describes it as "a great sounding bass distortion by J. Michael Pedals," and the project is "based on the Big Muff™ distortion, but tuned for bass"1. The kit is built around a true-bypass switching arrangement using a heavy duty 3PDT footswitch, listed in the bill of materials as Sw11.
For a bass player, the Deluge offers a way to build a distortion pedal voiced for the low end without designing a circuit from scratch. It shares its DNA with the most famous fuzz family in guitar history, and it comes with a small but real track record: builders on the Guitar FX Layouts blog have verified the layout and reported working builds2.
A Big Muff variant tuned for bass
The Deluge is not an original circuit from the ground up. General Guitar Gadgets states plainly that it is based on the Big Muff distortion and tuned for bass, and that it is built on their BMP PCB, the same board used for their Big Muff projects. When you buy the kit, the kit bag is a BMP kit bag with the small parts bag labeled "Deluge"1.
That lineage matters. The Big Muff Pi, first released by Electro-Harmonix, is a fuzz/distortion sustain pedal; Kit Rae's history of the circuit records that Mike Matthews wanted "a three knob distortion unit in a bigger enclosure, one that would have a lot of sustain"3. Electro-Harmonix later produced bass specific versions of its own, including the Deluxe Bass Big Muff Pi, which Kit Rae describes as essentially the V11 Bass Big Muff circuit, "a slightly lower gain, slightly less bassy version of a Green Russian Big Muff with a brighter mid range," sitting in the Sovtek tone family with a heavy, fat, but smooth distortion4. The Deluge sits in the same tradition: a four stage Muff style circuit re voiced so the low end survives.
The blog Guitar FX Layouts spotted the project at General Guitar Gadgets and laid it out for veroboard builders in February 2018, judging from the demo clip that "it sounds pretty nice, but then again how can you go wrong with anything with big muff origins"2.
"from the clip it sounds pretty nice, but then again how can you go wrong with anything with big muff origins."
The controls
The Deluge keeps the classic three knob Muff control set. Each control is a single potentiometer on the board1:
| Control | Potentiometer | Taper |
|---|---|---|
| Sustain (R6) | 100k | Log (audio) |
| Tone (R20) | 100k | Linear |
| Volume (R25) | 100k | Log (audio) |
Sustain sets the gain feeding the clipping stages, which in turn governs how much sustain and how much grind you get. Tone tilts the output between bass and treble, the same way the tone control on an Electro-Harmonix Big Muff does; on the EHX Deluxe Bass Big Muff Pi, for comparison, the tone knob "provides a range of sounds from high treble to deep bass on the distorted effect only," with clockwise rotation reducing bass and increasing treble5. Volume sets the output level.
Parts, jacks and power
The bill of materials gives the working parts of the circuit1:
- Q1, Q2, Q3, Q4: 2N5089 transistors, the four gain stages of the Muff style circuit
- D1, D2: 2N5457 FET transistors used as clippers, with special installation instructions on General Guitar Gadgets' Technical Help / Building Kits pages
- Sw1: heavy duty 3PDT footswitch for true bypass switching
- B1: 9 volt battery, not included in the kit
The jacks and power connections are1:
| Reference | Part |
|---|---|
| J1 | Stereo quarter inch jack (input) |
| J2 | Mono quarter inch jack (output) |
| J3 | DC jack |
The stereo input jack is the standard arrangement for battery powered builds: the battery negative connects through the ring of the jack, so the battery is disconnected when the input plug is removed. The DC jack allows the finished pedal to run from a power supply instead.
The FET clippers are the one part of the build that needs care. General Guitar Gadgets provides special instructions for installing 2N5457 transistors as clippers, on the Technical Help / Building Kits pages of their site1. FETs used as clippers do not drop in the way diodes do, so follow the project documentation rather than substituting by eye.
What builders said
The Deluge has a documented builder record on Guitar FX Layouts. In February 2018, builder Paul_5 reported a successful build and the layout was tagged as verified2:
"Tag this one as verified, it's a lovely muff variant!"
In July 2018, builder wizombie87 confirmed a second working build: "verified used everything listed and it works perfectly"2.
The same thread carries two findings worth knowing before you build. First, a substitution that seems harmless is not: one builder reported "i swapped 1n4148 diodes for D1 and D2. the thing oscillates horribly," so the 2N5457 FET clippers should be treated as required, not optional21. Second, a mod with a payoff: Paul_5 found that "This thing becomes a REALLY great bass fuzz if you swap out the 1kΩ in the bottom left for a 330Ω (or thereabouts)"2. That resistor change pushes the circuit from distortion territory toward fuzz, which is where many bass players want a Muff style circuit to end up.
J. Michael Pedals also has other bass designs in the General Guitar Gadgets catalog, including the Adamu Bass Preamp/Distortion and the Krampus Bass OverDrive, for players comparing the Deluge against other circuits in the same family. For the wider field, see bass pedals1.
Videos
J. Michael Pedals
Questions
Is the Deluge Bass Distortion a Big Muff clone?
It is based on the Big Muff distortion circuit but tuned for bass, and it is built on General Guitar Gadgets' BMP PCB. Builders describe it as a Muff variant rather than a straight copy, since the part values and clipping stages are chosen for bass frequencies.
Is the Deluge sold as a kit?
Yes. General Guitar Gadgets sells it as a bass distortion kit or project. The kit bag is the same BMP kit bag used for their Big Muff projects, with the small parts bag labeled Deluge. A 9V battery is not included.
Does the Deluge run on a 9V battery?
Yes. The bill of materials lists a 9 volt battery, though it is not included in the kit. The project also has a DC jack, so it can be powered either way once built.
Can you use 1N4148 diodes instead of FET clippers in the Deluge?
Not safely. The design calls for 2N5457 FET transistors as the clippers in the D1 and D2 positions, and General Guitar Gadgets gives special instructions for installing them. One builder who substituted 1N4148 diodes reported that the pedal oscillated horribly.
What mod turns the Deluge into a bass fuzz?
Builder Paul_5 reported that swapping the 1kΩ resistor in the bottom left of the board for a 330Ω value, or thereabouts, turns the pedal into a really great bass fuzz.
Sources (5)
- Deluge Bass Distortion: DIY Kit & Schematic, General Guitar Gadgets, 2014-07-13
- Guitar FX Layouts: Deluge Bass Distortion, Guitar FX Layouts (tagboardeffects.blogspot.com), 2018-02-11
- The Big Muff History of All Versions Part 1, Kit Rae (kitrae.net), 2020-03
- The Big Muff History of All Versions 3, kitrae.net, 2017-03
- Deluxe Bass Big Muff Pi 2, Electro-Harmonix (ehx.com)
