Dumbles are used by such artists as Carlos Santana, John Mayer, Robben Ford, Larry Carlton, Eric Johnson, Stevie Ray Vaughan, Ben Harper, Lowell George, Steve Lukather, Sonny Landreth, Jackson Browne and David Lindley.
In a 1985 Guitar Player article it was stated that Dumble amplifiers were selling for as much as $5,000. You couldn’t touch one today for $15,000.
They are manufactured for rock music and are tweaked to have a very sweet sounding distortion. Dumble uses only the best electronics in his amplifiers. I read that he often covered the plate resistors and capacitors in silicon or epoxy to prevent others from mimicing his proprietory technology. Despite these precautions, there are a handful of companies that provide Dumble DIY clones. And other companies sell guitar amplifiers based on Dumble’s circuits.
Dumble makes different models and will customize the amp to fit the artist.
Controls include Bright, Deep, Midrange, Boost (by disconnecting the treble and bass potentiometers, this gives the preamp more power.) A Rock/Jazz switch changes the voicing. Through the use of differing preamp circuits, Dumble amps can provide a clean tone or a singing distorted tone. Think David Lindley with Jackson Browne.