2024 AmpRx BrownBox Tube Amplifier Input Voltage Attenuator

Bay Area Vintage Guitars is proud to be an authorized deal of the AmpRX BrownBox. We recommend a BrownBox for Vintage and New amps, especially tube amps. If you are a working musician, you know how different venues offer many ranges of voltage and amps. This can not only cause damage to your amp and rig but can tremendously affect your tone and sound. Eliminate the guesswork at every gig and venue with the BrownBox!

• 5-year parts and labor. 
• Made in the U.S.A.

Overview via AmpRX:

BrownBox was created to provide a safe range of voltage reduction levels for vintage tube amplifier designs—the same era-correct voltage levels the amps were designed around. Our products can also be used with modern solid-state amp designs, protecting them from potential overvoltage conditions. 

The dynamics of a vintage amp supplied with the proper line voltage are optimized. It will sound and respond as originally intended, revealing the circuit's true harmonic content. This is the starting point, the basis of the signal chain, and where serious musicians begin creating a signature tone.  

Most vintage tube amps respond more harmonically and are touch-sensitive with optimized voltage. Placing these circuits back into balance reveals the amp's authentic tone fundamental, a tone that can truly blossom. 

For the Tube Tone Purist, no pedal or attenuator can replicate the heavenly response of dry, purely saturated tubes. Pedals and attenuators have their place, but they should be used to color your tone, not create it.

Everyone can enjoy a multi-dimensional, pure tube tone if they know where to start. 

BrownBox is not a variac. Unlike a variac, Brownbox cannot accidentally harm or destroy your amplifier. The maximum input voltage available using BrownBox is your regional line wall voltage in bypass mode. All other selections are reduction levels that you determine sound best for your amp. 

BrownBox employs a proprietary custom-wound toroid transformer intended for use with one amplifier. Check your amp's input wattage rating before use. Our proprietary transformers are custom-wound exclusively for use with tube amplifier designs but can and should be used with Solid state circuits - 

Technical background interest:
Consider this: Throughout the design process, we tested with a non-modded vintage Fender Bassman ( 5F6A) as part of our testing platform. One of the most important electrical design elements was measuring the variable current levels that the amp would draw at different line levels.
• Testing was performed at control levels between 105 V.A.C.V.A.C. and 126 V.A.CV.A.C. 
• Testing indicated current levels of 0.7 and 1.8 amperes consecutively. 

Knowing those factors enabled us to build exceptional electrical stability by creating a transformer with a current rating 2.5 times greater than the highest test result of 1.8 amperes. 

BrownBox was created by a team of experienced players and technicians with the professional player in mind. That meant it must be intuitive and easy to use every time. It must also have a road-rugged design and be able to take abuse. It must be practical and superior to any other voltage-reduction option.

BrownBox is completely proprietary in design and function and has a lifetime warranty with normal use. 

• Easy to read, back-lit L.C.D.L.C.D. display enabling real-time voltage and amperage monitoring, also useful for diagnostics.
• Tough road, rugged construction.
• Proprietary transformer designs are wound exclusively for tube amplifiers, an industry first!
• Filament soft-start in full reduction mode. 
• A powder-coated E.M.F.E.M.F. neutral housing. In-rush current protection, fused overload protection.
Silent, cool operation.
• A custom-wound 5-amp proprietary transformer will supply 540 watts max@ 120 Vac. It is designed for mid- to larger Amps, such as Fender Bassman, Marshall 50s/100s, Etc., Parallel, or( DUAL) amp rigs.

Be sure to check the manufacturer's info plate on the rear of the chassis for input watt requirements, or simply call us. We love to help.

Free shipping in the Continental U.S.!