NAMM 2025: AmpRx has sought to shake things up for tube amp users by releasing the Brownie – a nifty voltage controller tool that looks to optimize the tone and performance of valve-loaded guitar amps.
Described as “the first of its kind”, it’s a gadget that will likely especially pique the interests of Eddie Van Halen fans – or, indeed, anyone looking to emulate the revered ‘Brown Sound’ high-gain guitar tone he championed.
The basic premise of the Brownie is simple: it lets players “increase and decrease voltage with volt by volt precision”, offering unparalleled control, flexibility and protection for modern tube amps.
Building on AmpRx co-owner and CEO Cassandra Sotos’ existing BrownBox device, the Brownie lets you dial in the exact voltage required or desired, meaning a consistent supply of power will be fed into your tube amp no matter where you’re playing.
Naturally, such power considerations are crucial for consistent guitar tones, and the impact that voltage fluctuations in different locations can have on one’s tone can be drastic. Kirk Hammett, for example, has been vocal in the past about why he thinks Marshalls sound better when powered in the UK.
The benefits go beyond tonal considerations, too. As AmpRx explains, the ability to consistently feed your tube amp with the correct voltage will also extend its shelf life.
In practice, the sole knob can be used to decrease voltage in one volt increments, or increase it by three or five volt steps, with a digital display screen showing the chosen power. There’s also both 2A and 4A fuse options depending on what amp it’s partnered with.
It has the potential to be a pretty powerful accessory for tube amp users, especially – as mentioned – for those after that EVH-style Brown Sound. To create that OG amp tone, Van Halen would famously use a Variac to lower the wall voltage going into his amp, then crank everything up to 10.
The Variac thus served as a de facto output control for Van Halen, who developed a way to achieve his cranked amp tones without the ear-splitting volume levels that came with it.
Speaking to The Smithsonian’s National Museum of American History in 2017, Van Halen once recalled (via Warehouse Guitar Speakers), “I went to this place called Dial Radio and asked, ‘Do you have any variable voltage transformer that I can use like a light dimmer?’ He said, ‘Yeah I got this thing called a Variac.’
“I take it home and plug the amp into it and I’d lower the voltage from like 110 slowly down to 100 and... the lowest I ever went was like 60,” he went on.
“Depending on the room we were playing I’d set it anywhere between 60 and 100 because the only way the amp sounded good was with everything all the way up, so that became my volume knob.”
It has proved to be especially challenging to recreate that amp tone over the years – not least because of the volumes at which the Brown Sound was heard – but the Brownie could help overcome those issues.
The Brownie is available now for $299.
Visit AmpRx for more.
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