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AmpRx - BrownBox - Input Voltage Attenuator
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AmpRx - BrownBox - Input Voltage Attenuator AmpRx - BrownBox - Input Voltage Attenuator AmpRx - BrownBox - Input Voltage Attenuator AmpRx - BrownBox - Input Voltage Attenuator AmpRx - BrownBox - Input Voltage Attenuator

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AmpRx - BrownBox - Input Voltage Attenuator


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The BrownBox from AmpRX is a voltage attenuator for tube amps, whether it's a vintage classic or the latest modern build. Modern power typically runs at higher voltages than when the classic tube amp circuits were originally designed, and the BrownBox delivers a great way to lower the voltage in the studio, at home or at a gig.

The BrownBox can also extend the life of the power tubes in your amp by providing the attenuated voltage levels, which keeps your power tubes running optimally. This not only increases power tube life, but it also has the added benefit of delivering voltage levels similar to the original vintage-spec, which can improve amp performance

From AmpRx:

Today, we should be receiving 120V AC from the wall, but depending on where you are and what time of day it is, you can receive anywhere from 120V to 129V. That’s not good for your amplifier, or your ears. Depending on the specifics of your particular amplifier, you might discover that it runs optimally at as low as 112VAC. You can’t expect an amplifier that wants 112VAC to sound anywhere near the way it should at 129VAC.

The BrownBox features a proprietary 5 Amp transformer and flexible voltage attenuation options that let you bring your power input down to an optimal level, resulting in significantly improved amplifier performance.

Not only that, the BrownBox itself is the very thing that can help you find your Magic Number. You may have never even heard or felt your amplifier running on optimized voltage. The BrownBox has an easy to read LCD screen and an onboard voltmeter so you will always know exactly what voltage you’re receiving from the wall before you ever plug in your amplifier. Play through your amplifier at as many different voltages as your heart desires and you’ll hear the difference.

When the dynamics of a tube amplifier 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.

  • 120 Volt AC, 60 Hz, 5 Amp Voltage Attenuator supplies up to 540 Watts, designed for small or mid to larger sized amplifiers (i.e. Fender Deluxe/Bassman/Twin, Marshall 50w/100w, Vox AC30). Can also be used for parallel or dual amp rigs
  • Easy to read back-lit L.C.D. display enables real-time voltage and amperage monitoring - also useful for diagnostics
  • Two attenuation modes to help to fine-tune your voltage
  • Proprietary transformer design wound exclusively for use with tube amplifiers, an industry first
  • Equal or attenuated voltage output and a 5 amp fuse with in-rush current protection ensures that you will never accidentally overload your amplifier
  • Powder coated EMF neutral housing and tough road rugged construction
  • Silent, cool operation
  • Input: 120VAC, 60 Hz; Standard IEC AC cable
  • Output: Two AC Grounded Outlets; Voltage Reduction Selectable
  • Power Handling: 5 Amps at 120VAC, 60 Hz, up to 540 Watts

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Call us at 800-747-9980 or send us an email at - we're here to help! All of us at Mass Street Music are musicians, and we're dedicated to helping you find exactly what you're looking for. You can also check out our Staff Page if you'd like to email one of us directly.

Any new or used gear $25 or over gets shipped to you for FREE via our favorite carrier, Fed Ex – ground, to all 'lower 48' U.S. states and we offer a 7 day return policy. Alaska and Hawaii, expedited shipping, international shipping are more. We also ship around the globe. Read more about our Shippping.