Voodoo's Trace Davis working on one of Richard Fortus' heads.

Trace Davis, Voodoo Amps founder and president, says that when he was growing up his father taught him that anything worth doing was worth doing well.

“It wasn’t that he was trying to be a hard-ass,” chuckles Davis. “It was just the approach he had learned in the military for six years. He truly believed that if you’re going to do something, you really have to sit down and do it properly. You have to have a passion for it or you’re not going to excel—and I really have a passion for this because I play guitar and I love music.” Voodoo’s growing clientele is a testament to Davis’ passion. Current Voodoo amp or amp-mod players include such notables as Billy Gibbons, Joe Perry, Vivian Campbell, Doug Aldrich, and Bill Kelliher.

Of course, knowing what each amp component does is important for any amp builder, but Davis says what he’s interested in is how each component affects the amp’s feel. That process is more art form than science, so there are no hard and fast rules, but Davis says that over the years research has helped him develop an intuitive sense for it. His journey, however, began accidentally.

Lightning Strikes
It seems almost every amp builder starts out by having to fix something out of necessity rather than actual curiosity, and Davis is no exception. In 1996, he lived in Binghamton, New York, and spent his time shuttling back and forth to New York City working as both a freelance recording engineer and session guitarist.

“It’s not fun when you’re fighting for every note—you start thinking too much about playing rather than performing or recording. You don’t want to go, ‘Argh, I’m fighting with my gear again.’”
—Voodoo Amps’ Trace Davis

“I had about 17 different amps—not counting combos or cabs—and depending on what someone needed, I could mix and match,” he recalls. One of those amps was a 1969 Marshall plexi. “You could just put a microphone in front of it, and that was it. Everyone loved it. But then one day the bassist from the band I was in at the time was playing through it when lightning hit really close by. The lightning fried the tubes and the output transformer.”

Fortunately for Davis, he’d been around electronics most of his life. His father worked at Westinghouse, where he oversaw the manufacturing, production, and quality control of tubes—which made the prospect of repairing the plexi seem more plausible. “I was always around it, but I didn’t have any interest in it until I opened up that amp to try to figure out what was wrong.” Upon doing so, Davis remembers thinking to himself, “I’ll just get a Marshall-authorized output transformer and it’ll be fine.” And he did, but when he put the amp back together and plugged it in, he says it sounded like a shadow of its former self. “I could’ve just heaved the thing out into the driveway and called it a day,” he laughs wryly. “So I had ‘it’—and then ‘it’ was gone.”

When asked to elaborate on what was so magical about the “feel” of both his old Marshall and what he’s aiming for with his own amp designs, Davis compares it to the string setup on a guitar. “To most players, tone is just what comes out of the cabinet—the sound. But when you have a guitar in your hands, you want it to feel good: Transitioning from string to string should feel good. Bending and vibrato should feel good. Let’s say you’re using .010-gauge strings—you don’t want it to feel like .011s or .012s. That’s really stiff. You want .010s to feel like .008s or .009s. It’s not fun when you’re fighting for every note—you start thinking too much about playing rather than performing or recording. You don’t want to go, ‘Argh, I’m fighting with my gear again.’”

Voodoo's main repair tech, Dan Stillwell, at his workbench.

There’s no test gear for something as nebulous as feel, but that’s where Davis says artistry comes into play. “You can line up the voltage, but if you’re using different caps, they might be the same value, but they can feel stiffer,” he explains. “I’ve tried—and continue to try—every different kind of cap out there, whether it’s a coupling cap, a bypass cap, or a filter cap, just to know how they feel. Because everything has its place.”

More Than Meets the Eye
While new-old-stock tubes, capacitors, and resistors often get bandied about as sources of elusive amp mojo, Davis says his experience has taught him that output transformers are one of the oft-overlooked components that significantly contribute to overall feel. That realization first came when he was attempting to recover his plexi’s lost tone. He bought another old Marshall and experimented with moving components from one to the other. “When I got around to swapping the output transformer, it sounded noticeably better, though not exactly the same. That’s what got me really deep into this—trying to get back something I had lost.” The quest to capture that same tone and feel has become one of the driving forces behind the Voodoo brand.

“When you first start out doing this stuff, you tend to think it’s the caps and resistors,” he says. “You think to yourself, ‘The plexi had mustard caps, so that’s got to be the secret.’ I came into it backwards with transformers. The situation with my plexi made a massive difference for me. Comparatively, the transformers sounded radically different, but they weren’t supposed to. It was really obvious, like flicking a light switch on in a dark room.”

That doesn’t mean Davis dismisses the importance of smaller components. A clear understanding of caps, resistors, and voltage is essential, of course, and he’s done considerable homework. “I studied everything, including the metallurgy of what goes into forging the metal for the laminates and the wire and the insulation.” But when all’s said and done, he sticks to his guns on the drastic impact that quality transformers can have. “Even with such knowledge, it turns out that a profound difference can be made with transformers. It can make an amp sound and feel altogether different.”