NAMM 2025: AmpRx has unveiled the Brownie, a groundbreaking voltage controller designed to optimize the tone and lifespan of tube amplifiers. This compact device, described as “the first of its kind,” allows guitarists to precisely adjust their amp’s voltage with unprecedented control.
AmpRx Brownie – Unlocking the “Brown Sound”
The Brownie is particularly exciting for players seeking to emulate Eddie Van Halen’s legendary “Brown Sound.” Like Van Halen, who used a Variac to lower line voltage and achieve high-gain tones at manageable volumes, the Brownie enables players to fine-tune their amp’s power supply for optimal performance and tone.
Key Features
- Precise Voltage Control: Increase or decrease voltage in single-volt increments, providing unparalleled flexibility.
- Consistent Tone: Maintain consistent power delivery across different venues and power grids.
- Extended Tube Life: Proper voltage ensures optimal tube operation, prolonging their lifespan.
- Compact and User-Friendly: Easy to use with a single knob and a digital display.
- Available Now: The Brownie is available for purchase at $299.

Benefits Beyond Tone
The Brownie offers more than just tonal advantages. By ensuring consistent and optimal voltage, it helps protect your valuable tube amp investment and maximizes its overall performance.
Guitar Bomb Verdict
AmpRx’s Brownie represents a significant advancement in tube amp technology, offering players a powerful tool to achieve their desired sound while preserving their equipment.
MSRP – $299
More Amp Tone Products at NAMM 2025
NAMM 2025 appears to have some great new products that could help guitarists achieve great amp tones, including the new Celestion Peacemaker 12″ speakers.
Check out our How to Achieve the Perfect Guitar Amp Tone article to help your tone.