The Seismic / Shift is a JFET boost pedal kit from Mod Electronics, a build-it-yourself take on one of the earliest effects ever used on stage. The maker describes it as a pedal that "adds subtle color to a guitar's sound while maintaining the natural tone of the guitar," and says it "pairs nicely with amps and other pedals." It sits in the boost lane: a clean lift rather than a drive pedal, closer in spirit to the preamp section of an old tape echo than to an overdrive or distortion circuit.1
The circuit and where it comes from
The Seismic / Shift is a JFET boost, meaning it uses a junction field-effect transistor to lift the signal. Mod Electronics describes it as "a JFET boost based on one of the earliest effects to ever be used on stage."1 Writing when the kit was announced, Paolo De Gregorio of Delicious Audio put a finer point on that lineage:
"This rather simple clone is a recreation of the preamp section of the vintage Echoplex."
The kit is also the opening entry in a new line from the maker. "The Seismic / Shift pedal kit is the introduction to the Nexus Series from Mod Electronics," the product page states, and Delicious Audio confirmed "The Seismic / Shift is the first kit in this line" when it was covered in November 2021.12
Building it
Mod Electronics rates the Seismic / Shift a "1 Build Difficulty," the easiest end of its scale.1 The Nexus Series differs from the company's earlier kits in how it is put together: "This series features a PCB base rather than the Mod Electronics' traditional point-to-point wiring kits," so the builder solders components to a printed circuit board instead of wiring everything by hand between terminals.1 For a player who has never built a pedal, that makes this a reasonable first project.
The kit comes with documentation from the maker:
- Seismic / Shift instructions, published by Mod Electronics1
- Seismic / Shift PCB schematic, published by Mod Electronics1
Power and enclosure
The pedal operates on both 9VDC and 18VDC, with a center negative power supply required for use, and that supply is not included with the kit. There is no battery connection, so an external supply is the only way to run it.1
| Specification | Value |
|---|---|
| Power | 9VDC or 18VDC, center negative1 |
| Current draw | 8mA at 9VDC, 16mA at 18VDC1 |
| Battery | None, no battery connection1 |
| Power supply included | No1 |
| Enclosure | Standard 1590B, 4.4" x 2.4" x 1.2"1 |
| Build difficulty | 11 |
The Seismic / Shift has no battery connection and ships without a power supply. A center negative supply is required, and running it at 18VDC doubles the current draw to 16mA.1
The finished pedal uses a standard 1590B enclosure measuring 4.4" x 2.4" x 1.2", the common compact stompbox size, so it sits on a pedalboard like any standard pedal.1
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Questions
Does the Mod Electronics Seismic / Shift run on a battery?
No. Mod Electronics states there is no battery connection on the Seismic / Shift, so it must be powered from an external supply. A center negative power supply is required, and it is not included with the kit. The pedal draws 8mA at 9VDC and 16mA at 18VDC, so a standard supply handles it easily.
What enclosure does the Seismic / Shift kit use?
The kit uses a standard 1590B enclosure measuring 4.4 x 2.4 x 1.2 inches. That is the most common Hammond-style box for compact pedals, so it fits a pedalboard like any standard-sized stompbox once the build is finished.
How hard is the Seismic / Shift kit to build?
Mod Electronics rates it a 1 on its build difficulty scale, the easiest end. The Nexus Series uses a PCB base rather than the company's traditional point-to-point wiring kits, which makes the Seismic / Shift a straightforward first build.
What is the Seismic / Shift circuit based on?
It is a JFET boost based on one of the earliest effects ever used on stage. Paolo De Gregorio of Delicious Audio describes it as a recreation of the preamp section of the vintage Echoplex tape echo unit.
Sources (2)
- Seismic / Shift, Mod Electronics (modkitsdiy.com), 2026
- New Pedals: Mod Electronics Seismic / Shift (DIY Kit), Delicious Audio, 2021-11-23