What does a Dumble ODS-100 Overdrive Special built to Alexander “Howard” Dumble’s personal specs sound like? Pretty, pretty good...

Vertex Effects has spent some quality time with one of the world’s most sought-after guitar amps of all time, a Dumble ODS-100 Overdrive Special that Alexander “Howard” Dumble built for himself before finishing it off for one of his lucky clients.

This is tube amp porn, borderline NSFW, featuring a unicorn ODS-100 in a rig that includes some very rare and custom-built kit. The video is great but be warned that it might change how you think of your own amp at home. 

You’ll want some quality headphones on. You’ll find Gabriel Bergman on the electric guitar, Vertex’s Mason Marangella walking us through the rig’s features. But it’s the Overdrive Special that does all the talking. 

What makes it special? That’s what Bergman and Marangella are there to find out. But ahead of the jump, they knew it had to have something. All Overdrive Specials have it. This OD-100 might just have something extra.

Marangella has proven a successful prospector for sniffing out Dumble amps, getting up close and personal with the Overdrive Special that Jason Isbell calls “possibly the greatest amplifier ever made”, having some demo time with Eric Johnson’s Dumble Manzamp preamp and Odyssey power amp setup, i.e. the Ultimate Eric Johnson Rig. 

This rig might just outdo them all. Not only do we have a Dumble spec’d OD-100, we have a super-rare Dumbleator tube-buffered effects loop, with a TC Electronic 2290 rack-mounted delay and a DigiTech Hardwire RV-7 reverb pedal – a favourite of Marangella’s for its Lexicon chip giving it the quality of vintage PCM rack units. 

Not that the RV-7 is doing too much heavy lifting here. “We’re just keeping it like you would find with Robben Ford,” says Marangella. “A nice little plate reverb just to add a little bit to it but nothing too overwhelming.”

The cabinet is a Jensen-loaded Dumble 2x12 that was built for Todd Sharp. Now, Sharp knows his apples. He played lead guitar for Hall & Oates when he was still a teenager, would later session with some of the best, before eventually founding his own amp company, Todd Sharp Amplifiers.

Jensens are an unorthodox choice, notes Marangella, but inspired, too. The rig was voiced for the original owner’s Telecaster – and they have the original Tele there to demo it. It’s still a toss-up as to whether it sounds better with Bergman’s Les Paul or the Tele. 

There was something else that makes this OSD-100, serial number 195, special. The amp head cabinet was originally made for Robben Ford, and even has some tape on the top that betrays its provenance.

“The person who commissioned this from Dumble requested that this be in a silver chassis,” says Marangella. “Because there weren’t many of the silver chassis at time when this particular one was built. And at the time he built that chassis, he didn’t actually have an available head cabinet and this head cabinet had belonged to Robben Ford, and, in fact, there is a piece of tape on top of this, that’s taped down, that says, ‘Rick, this is the amp. This is the amp.’ And that’s to indicate to Rick Wheeler, who is the technician for Robben Ford and would often go on tour with him, that this is the one he needed.”

We couldn’t put a price on the ODS-100. Furthermore, it ain’t for sale and the owner wishes to remain anonymous. The Dumbleator effects loop, which might set you back up to $50,000, only adds to the impression that this is a Holy Grail rig. For most of us, it’s not even an amp to aspire to owning, yet it remains a helpful, inspiring reference tone to calibrating our tastes and what we want from our sound. 

Marangella has used those tones as a lodestar, with many of his Vertex Effects drive pedals inspired by Dumble designs. You can learn more at Vertex Effects, and check out some more of Marangella’s videos with vintage Dumbles at the Vertex Effects YouTube channel.