Alexander Dumble Personally Owned & Built Reactive Load Box

This reactive load box was owned and built by renown amp builder Alexander Dumble and used by him in his legendary workshop known as “The Amp Lab”.

This reactive load box is a device that safely absorbs the high-power output of a tube guitar amplifier and mimics a real speaker's complex electrical resistance so you can record or play without a physical speaker cabinet. 

Needless to say this is easily the most interesting and unique reactive load box in existence.

It’s an actual Dumble built reactive load box….how incredible is that?

Measures 8”x7”x4”.

Very Good condition (see pics). 

This item appears to be working, but it is being sold "as is" and is unaltered from how it was found in Dumble's Amp Lab. There may be modifications or missing parts, it is in the exact condition he kept it in. 

Comes with proof of authenticity including paperwork from original sale and copy of certificate of authenticity.

This is a rare opportunity to own an actual piece of guitar and amplifier history. This is an actual piece of equipment that helped build the tone and the sound of some of the most influential music of all time.

Alexander Dumble hand-built and tuned each of his legendary amplifiers by ear. He utilized vast collections of hand-tested electrical components (capacitors, resistors, and tubes), measuring their specific tolerance levels with multimeters, oscilloscopes, and frequency analyzers to achieve meticulous, hyper-specific frequency bandwidths.

Howard Alexander Dumble (1944–2022) was an eccentric, legendary California electronics engineer widely considered one of the greatest boutique guitar amplifier builders in music history. Operating as a strict, one-man business, he personally handcrafted fewer than 300 custom vacuum-tube amplifiers over several decades. Today, Dumble amplifiers are among the rarest and most expensive pieces of musical equipment in the world. Guitarists that are among the unique and elite crowd of Dumble players include Robben Ford, Stevie Ray Vaughan, Jackson Browne, Joe Bonamassa, John Mayer, Carlos Santana, Jason Isbell, & Eric Clapton. 

Please message me with any questions.

Please check my other listings, I’m selling a few other owned and used items from Alexander Dumble’s personal collection this month.