AmpRx

AmpRx are all about giving your gear the proper juice. Their flagship gizmo, the BrownBox, is an adjustable AC power supply designed to make sure your valve amps and tube gear get exactly the voltage they were born to run on. Just plug the AmpRx BrownBox into the wall, dial in your voltage and then run your amp through it — easy as that.

BrownBox: why proper voltage makes your amp sing

When tube amps get the correct line voltage, they behave exactly as the designers intended. You get the real harmonic character of the circuit, the feel snaps into place and you massively cut down the risk of annoying, wallet‑draining repairs. Basically, your amp finally breathes the way it’s supposed to!

Real players, real tone

BrownBox users rave about how their tone suddenly “clicks”. We’re talking better harmonics, sweeter dynamics and improved touch response. And plenty of top-tier players already swear by it, including legends like Peter Frampton, Phil X, Josh Smith, Andy Wood, Greg Koch and a bunch more.

Made by musicians

AmpRx was founded in Nashville by professional musicians Cassandra Sotos and Clark Singleton, so they genuinely understand the madness of chasing tone and the importance of trusting your rig. They stand proudly behind the BrownBox because it’s built by players, for players.