The Drunk Beaver Trainer TS-15 MKII is a preamp-style overdrive pedal based on the Canadian Trainer TS-15 amp. It landed towards the middle of June 2025 and carries Bass, Treble, Gain and Master controls, plus two toggle switches that shape the EQ and the input gain. Guitar Pedal X described its output as "punchy, percussive, raw, angular and muscular garage punk output, with gain from Overdrive to High Gain"1. It sits among preamp pedals that put an amp-style gain stage on the board.
The controls
| Control | What it does |
|---|---|
| Bass | Low EQ |
| Treble | High EQ |
| Gain | Amount of drive |
| Master | Output level |
| EQ toggle (ISS4 / ISS6) | Selects between two tone stack voicings |
| Input Gain toggle (Normal / Low) | Normal is livelier; Low softens it |
The two toggles are the MKII's distinguishing feature. On the EQ switch, ISS4 adds bass, bite and punch, while ISS6 reduces bass and moves the mid scoop to 450Hz1. The names come from Traynor's own revision system: Traynor refer to their revisions in the form of an ISS code, and ISS4 and ISS6 change out the entire tone stack, which consists of an array of different capacitors1. The Input Gain switch offers Normal, described as the livelier setting, and Low, which softens the response1.
What is different from the original Trainer TS-15
The MKII uses the same core components as the original Trainer TS-15 pedal, with two additional toggle switches: the ISS4/ISS6 EQ selector and the Normal/Low Input Gain control1. Those two switches are what the "two additional controls" of the release add to the pedal's front panel.
What reviewers said
Guitar Pedal X's Stefan Karlsson reviewed the pedal twice in 2025. In July, at release, he called it "seriously one of the liveliest preamp pedals out there"1. In December, listing it among the year's boost and overdrive pedals, he wrote:
"A massive improvement over the original - this one is especially fun to pay - has a proper rock 'n' roll delivery to it"
Related Drunk Beaver preamps
Drunk Beaver has built a range of amp-style preamp pedals, including the Zhytomyr Sunset Preamp, the Ternopil Pentode Preamp and the more recent Kostiantynivka Dominator Preamp.
Videos
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Questions
What does the ISS4/ISS6 switch do on the Trainer TS-15 MKII?
The EQ toggle selects between two tone stack revisions in the style of Traynor's ISS codes. ISS4 adds bass, bite and punch, while ISS6 reduces bass and moves the mid scoop to 450Hz. Traynor used these ISS codes to mark revisions to their amps, and ISS4 and ISS6 change out the entire tone stack, which is an array of different capacitors.
What does the Input Gain switch do?
The Input Gain toggle has two positions, Normal and Low. Normal is described as the livelier setting, while Low softens the pedal's response. It sits alongside the EQ switch as one of the two toggles added on the MKII version of the pedal.
How much does the Drunk Beaver Trainer TS-15 MKII cost?
Guitar Pedal X listed the Trainer TS-15 MKII at $150 in its December 2025 round-up of the year's boost and overdrive pedals.
What is different from the original Trainer TS-15 pedal?
The MKII uses the same core components as the original but adds two additional toggle switches: the ISS4/ISS6 EQ selector and the Normal/Low Input Gain switch. Guitar Pedal X called it a massive improvement over the original.
What amp is the Trainer TS-15 MKII based on?
The pedal is based on the Canadian Trainer TS-15 amp, made by Traynor. The pedal's EQ switch borrows Traynor's ISS revision codes, which marked changes to the amp's tone stack.
Sources (2)
- Guitar Pedal X, Guitar Pedal X, 2025-07-21
- Guitar Pedal X, Guitar Pedal X, 2025-12-04
