The Decades Pedals MultiJam is a distortion pedal that revives the Multivox Big Jam Distortion, a 1978 design that Guitar Pedal X calls one of the key successes of the Big Jam pedal series1. It is the first release from the new brand Decades Pedals, sold as the MultiJam Overdrive & Distortion, and it is available now from the Decades Pedals Webstore2.
Where it comes from
The original Big Jam Distortion was commissioned by Multivox and manufactured by Firstman Electronics, also known as Hillwood, and came in a distinct 1970s-era enclosure with slider controls1. Guitar Pedal X places it among American 1970s-era hard-clipper distortions, adjacent to but distinct from the early MXR Distortion+ and DOD2501.
Decades Pedals' designer Quentin built the revival with the same components as the original, including what Guitar Pedal X calls the rare UA741 op amp, C945 transistors and, in particular, the 1N60 germanium diodes1. The reviewer's verdict on the work: "Quentin has done an excellent job in bringing the Big Jam Distortion up to date"1.
Controls and modes
The MultiJam carries five controls, two of them additions to the original circuit12:
| Control | What it does |
|---|---|
| Volume | Output level1 |
| Drive | Amount of overdrive and distortion2 |
| Tone | Tonal shaping2 |
| Fat Cap | Off/On switch, adds volume, punch and definition1 |
| Mode | Vintage / Modern; Modern provides more output and headroom2 |
The Fat Cap switch and the Modern mode are the two mods over the 1978 circuit. Guitar Pedal X describes them as adding "more volume, punch and definition"1, and notes in the February review that the Modern setting gives more output and headroom2.
What it sounds like
Guitar Pedal X attributes the pedal's character to its clipping combination: "That combination of clipping delivers the most exceptional vibrant and richly textured output - which ramps up quickly from Overdrive to Distortion"2. In the March review, the same publication found it "slightly more textured and more interesting than the Distortion+ and DOD250, but could ideally do with more volume and gain overall"1. The reviewer's overall take: "This is a superb everyday overdrive and distortion - I love the extra mods here - both of those are highly useful for me"2.
Guitar Pedal X also reports that the original Big Jam design has a following in Nashville: "This is one of those Nashville secret weapons, and there is already a clique of players who favour this distortion"1.
Overdrive or distortion?
The pedal is sold as the MultiJam Overdrive & Distortion, and Guitar Pedal X describes its response as ramping up quickly from overdrive to distortion2. The circuit it revives belongs to the hard-clipper distortion family, so it sits between the two categories rather than squarely in one; players comparing it with other designs can start at the distortion pedal and overdrive pedal type pages.
Videos
Cameron Roo
PJ and the Beard
ToneBros and Decades Pedals
Questions
What is the Decades Pedals MultiJam based on?
The MultiJam is a revival of the Multivox Big Jam Distortion, a 1978 pedal commissioned by Multivox and manufactured by Firstman Electronics, also known as Hillwood. Guitar Pedal X reports that Decades Pedals' designer Quentin used the same components as the original, including the rare UA741 op amp, C945 transistors and 1N60 germanium diodes.
What does the Fat Cap switch do?
The Fat Cap switch is an Off/On control added to the original circuit. Along with the Modern mode, Guitar Pedal X describes it as adding more volume, punch and definition to the pedal's output.
What is the difference between Vintage and Modern mode?
The Mode switch selects between Vintage and Modern. Modern mode provides more output and headroom than the Vintage setting, which follows the character of the original 1978 circuit.
What clipping diodes does the MultiJam use?
The MultiJam clips with 1N60 germanium diodes, the same diode type used in the original Big Jam Distortion. Guitar Pedal X pairs these with the LM741 op amp and at least two C945 transistors in describing the pedal's circuit.
How much does the MultiJam cost?
The MultiJam lists at $250 from the Decades Pedals Webstore, a price reported by Guitar Pedal X in both February and March 2026.
Is the MultiJam an overdrive or a distortion?
It is sold as the MultiJam Overdrive & Distortion, covering both. Guitar Pedal X describes its output as ramping up quickly from overdrive to distortion, and the original Big Jam Distortion sits in the American 1970s hard-clipper distortion family.
Sources (2)
- Guitar Pedal X, Guitar Pedal X, 2026-03-26
- Guitar Pedal X, Guitar Pedal X, 2026-02-18
