The Tech 21 Hot-Rod Plexi is an analog distortion pedal that puts the signal path of a stock '68 Plexi-style amp in front of your own amplifier. Tech 21 announced it on October 17, 2013, and built it from portions of the company's all-analog SansAmp technology, which the press release said was done "to generate the organic tube amp distortion characteristics" of the vintage amps it is named after1. It was available exclusively through Guitar Center and Musician's Friend during its introductory launch1.
The controls and the two modes
The pedal runs in two modes. Stock mode reproduces the signal path from the input jack to the speaker jack of a stock '68 Plexi, without the speaker emulation, so it behaves like the front end of that amp rather than a full amp-in-a-box with a cab sim. Hot mode engages an extra "12AX7" pre-amp gain stage, and with its own level control it can kick in up to 28dB of pre-amp boost, which the press release called "a pretty insane amount of gain"1. Guitar Interactive Magazine's Jonathan Graham repeated that figure in his coverage3.
The front panel carries three main controls plus the Hot level:
| Control | What it does |
|---|---|
| Drive | Adjusts the overall amount of gain and overdrive1 |
| Tone | Cuts the high end without losing mids or getting muddy1 |
| Thump | Takes care of the low end for the resonant frequency of a 4x12 cabinet1 |
| Hot level | Sets the level of the Hot mode's pre-amp boost, up to 28dB1 |
The footswitch uses a silent-switching, custom footswitch actuator, so there is no mechanical clunk when you engage the pedal1.
Built on SansAmp technology
Tech 21 is known for SansAmp, the all-analog circuit design that has run through the company's products since the beginning4. The Hot-Rod Plexi incorporates portions of that technology to generate its tube amp distortion characteristics1. Tech 21, described by Guitar World as a "New York-based manufacturer"5, has applied the same approach across a range of pedals, including the Tech 21 Blonde, the Tech 21 U.S. Metal and the Tech 21 U.S. Steel, and the Richie Kotzen signature OMG, which also features a SansAmp section4.
What it does to your sound
Tech 21's own product material describes the pedal as inspired by vintage amps of the same nickname, and says that while those hulking stacks are known to need volume to deliver their character, the Hot-Rod Plexi can transform an existing amp without cranking it2. The company positions it as a way to "completely change the personality of a clean amp or use it as an instant mod to a dirty amp"23. Because Stock mode carries no speaker emulation, the pedal leaves the voicing of your own speaker and cab in place, with the Thump control shaping the low-end resonance associated with a 4x121.
The Hot-Rod Plexi draws only 5mA from a 9V DC center-negative supply2 and can also run from a 9V battery, which is not included1.
Videos
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Questions
Does the Hot-Rod Plexi take a battery?
Yes. The pedal is operable with a 9V battery, though a battery is not included with the pedal. It can also be powered from a 9V DC, center-negative supply, drawing 5mA, which is light enough that it should sit comfortably on most pedalboard power supplies.
What does Hot mode do on the Hot-Rod Plexi?
Hot engages an extra 12AX7-style pre-amp gain stage on top of the Stock mode signal path. With its own level control, Hot can kick in up to 28dB of pre-amp boost, which Tech 21's press material described as a pretty insane amount of gain. It can change the personality of a clean amp or act as an instant mod to a dirty amp.
Does the Hot-Rod Plexi have speaker emulation?
No. In Stock mode the pedal reproduces the signal path from the input jack to the speaker jack of a stock '68 Plexi, without the speaker emulation. The Thump control instead takes care of the low end for the resonant frequency of a 4x12 cabinet.
Where is the Hot-Rod Plexi made?
The Hot-Rod Plexi is manufactured in the U.S.A. Its maker, Tech 21, is a New York-based manufacturer known for the SansAmp line.
Sources (5)
- Tech 21 Introduces the Hot-Rod Plexi, Premier Guitar, 2013-10-17
- Hot Rod Plexi by Tech 21, RockBoard PedalPedia, 2026
- Tech 21 Introduces the Hot-Rod Plexi, Guitar Interactive Magazine, 2013-10-18
- Richie Kotzen RK5 Signature Fly Rig V3 by Tech 21, Premier Guitar, 2024-12-21
- Tech 21's SansAmp Character Plus pedals celebrate iconic pairings of amps and effects, Guitar World, 2022-05-23
