The Rock Master Guitar Tube Preamp is an early 90s tube preamp from Peavey, and its Ultra Gain channel is the part of it that mattered most. Peavey describes the original unit as what some consider the granddaddy of what became the Peavey XXX and JSX guitar amplifiers, most notably the Ultra Gain section1. That circuit has now been carried into a pedal: the Rock Master Preamp Pedal, a TransTube recreation of the Ultra channel circuit from circa 19901.
The Ultra Gain sound in a pedal
Peavey positions the pedal as delivering the highly sought-after Ultra Gain tones of the early 90s Rock Master Guitar Tube Preamp1. The maker describes its range as high-gain rock and metal, capable of super-saturated leads and punchy, tube-like clean tones2. Where the original unit used tubes, the pedal is analog and transistor-based, built on Peavey's TransTube technology with soft-clipping distortion1.
One specification matters for how it behaves in a board: the pedal steps its internal supply up to 30V rails from a 9V input. Peavey says this delivers the headroom high-gain players need1.
The pedal has no built-in speaker simulation. Peavey states it is intended to supercharge the front end of your amplifier, plug into a power amp, or be used with an external speaker emulator1.
Controls
| Control | What it does |
|---|---|
| Pre | Controls the amount of gain applied to the input signal3 |
| Post | Output level after the gain stage4 |
| Bottom | Low EQ4 |
| Body | Mid EQ, with a Mid Shift switch4 |
| Edge | Active plus/minus shelving control varying the high frequency boost and cut3 |
| Gain switch | Boosts overall system gain when engaged1 |
| Bypass | Footswitch bypass, described by Peavey as anti-click4 |
The EQ section runs wide: Peavey lists a range of plus or minus 15 dB across it4. The Mid Shift switch works alongside the Body control as part of the re-creation of the original Ultra channel4.
Where it came from
The original Rock Master Guitar Tube Preamp dates from the early 90s3. Peavey's own account is that it is what some consider the granddaddy of what became the Peavey XXX and JSX guitar amplifiers, most notably the Ultra gain section1, and Premier Guitar's press release repeats the same lineage3. The pedal is Peavey's re-creation of that original Ultra channel, complete with the mid-shift switch and the wide EQ range4.
The rest of Peavey's preamp pedal line
The Rock Master pedal is one of a series of preamp pedals Peavey announced at NAMM 2025, based on classic circuits from its own back catalog. The others cover different corners of the company's history:
- Peavey VTM Preamp Pedal
- Peavey Decade Preamp
- Peavey Session-LTD 400 Preamp Pedal
- Peavey Bandit Supreme Teal Stripe Preamp Pedal
For a player deciding whether the Rock Master pedal fits a board, the short version is this: it is a single-channel, analog high-gain preamp with no cabinet simulation of its own, meant to drive an amp or a power amp, with the EQ and gain structure of the Ultra channel that led to the XXX and JSX12.
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Questions
What is the Peavey Rock Master Guitar Tube Preamp?
It is a guitar tube preamp from the early 90s made by Peavey. Its Ultra Gain channel is the part players remember: Peavey describes the unit as what some consider the granddaddy of what became the Peavey XXX and JSX amplifiers, most notably the Ultra Gain section. Peavey has re-created that Ultra channel circuit in a modern analog preamp pedal.
Is the Peavey Rock Master preamp pedal based on the original tube unit?
Yes. Peavey describes the pedal as a TransTube recreation of the groundbreaking Rock Master Ultra channel circuit from circa 1990, with soft-clipping distortion. Internally it uses Peavey's TransTube transistor-based technology rather than tubes, and it runs on stepped-up 30V internal rails for headroom.
What does the Voicing EQ do on the Peavey Rock Master pedal?
The pedal's EQ section covers Bottom, Body and Edge. The Edge control is an active plus-or-minus shelving type control that varies the high frequency boost and cut, according to Premier Guitar's press release, and the EQ range is wide, at plus or minus 15 dB. A Mid Shift switch works with the Body control.
How is the Rock Master related to the Peavey XXX and JSX amps?
The original Rock Master Guitar Tube Preamp is what some consider, in Peavey's words, the granddaddy of what became the Peavey XXX and JSX guitar amplifiers, most notably the Ultra Gain section. The pedal carries that same Ultra channel circuit forward in pedal form.
Does the Peavey Rock Master pedal have more than one channel?
No. Peavey lists a single channel on the pedal, the Ultra Lead Channel, which re-creates the original Rock Master Ultra channel. It has a Gain switch and bypass footswitches, described by Peavey as anti-click.
Sources (4)
- Rock Master® Preamp Pedal, Peavey
- Rock Master® Preamp Pedal, Peavey
- Peavey Rock Master Preamp Pedal Arrives, Premier Guitar, 2025-09-24
- Decade™ Preamp Effects Pedal, Peavey
