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Amp Care Basics With Austen Hooks

Amplifiers can be seen simply as a means to an end. (Volume, that is.) But many electric-minded players—myself included—consider the relationship they have with their amps as much more personal than that. These wonder boxes are, after all, the final step in the signal chain. It’s our very last chance to make our guitars sound precisely the way we’d like them to before the signal passes into the air for anyone to hear. It kind of funny, then, how little most of us actually know about how our cherished amps work, or how to care for them. TLC is important, especially when it comes to vintage units.

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My mid-’60s Gibson Skylark recently needed a tuneup, so I took it to Los Angeles-based amp whiz Austen Hooks. Hooks is the go-to guy for lots of serious players in town—from the guys in the band Dawes to Jackson Browne—because he does consistently great work. Hooks not only has years of hands-on experience fixing all sorts of vintage electronics, he also holds a degree in electronics engineering from Texas A&M, so his perspective is both personal and academic. While chatting over the minor repairs my Skylark needed, our conversation casually drifted in the direction of the dos and don’ts of amp care. Hooks—in his casual, no-nonsense way—shared some essential things players can do, or avoid doing, to ensure reliable performance from their trusty tone machines.

Hooks’ first tip is concerned a move I’ve seen lots of players make: plugging a guitar into a tube amp, powering the amp on, then playing the guitar right away while the amp is warming up. What’s wrong with that? “There’s a reason why amps have standby switches,” Hooks says. “There’s a reason why no sound comes on when you first turn the amp on. The tubes haven’t reached their steady state yet. You really shouldn’t play through the amp until it’s completely warmed up. You could be damaging the tubes if you do, shortening their working life.” So, how long should we leave our amps on before making any noise? “Twenty or thirty seconds, more than five minutes isn’t necessary,” Hooks says.

On the other hand, he warns, we shouldn’t let our amps idle indefinitely prior to showtime. “Don’t let it sit there on full power—or even on standby—for three or four hours before you go onstage. If you’re gonna be away from it for that long, then just turn it off. Otherwise, the amp is still working, the transformer is still working. Turning the amp on and off a bunch of times isn’t great either, but I don’t think leaving it on for a bunch of hours is better than turning it off and back on once.” That’s really good to know for touring musicians who may be sound-checking at 4:00 p.m. for a gig that doesn’t start until well after dark.

This amp life-extension point led me to ask Hooks about a related issue. Let’s say you have one favorite rig that you use most the time, but you also own a few others that see use just once or twice a year. Should you fire the other amps up more frequently? That’s something I’ve heard a few amp techs recommend. “That’s a subjective thing,” Hooks says, somewhat gingerly. “I think exercising the caps [electrolytic capacitors found in all amplifiers] is a really good idea. Capacitors are like rechargeable batteries. We all know that, with our laptops, the batteries don’t last as long if you just keep it charged all the time and don’t exercise it. So I think it is a good idea to fire amps up once in a while—maybe a few times a year. Then again, there are so many stories of people finding a 40-year-old amp in someone’s basement, turning it on, and it works just fine.”

While tube and capacitor issues are very important, there’s another amplifier component about which Hooks is even more adamant. If he could have guitar players learn just one thing about their amps that is very important, he says, it’s what a fuse is and what a fuse isn’t. “Fuses are indicators, not problems. If your fuse blows and you replace it, that doesn’t mean everything is okay. First of all, always be sure use the exact fuse value that is recommended on the amp itself, or you risk doing a lot of damage. And if fuse blows more than once, then the amp really needs to be seen by a tech. A fuse is there to protect your amplifier from damage. If that amp draws too much current from the wall for some reason, it’s the fuse that says Nope, we’re not going to damage this amp, and shuts things down.

On the whole, players should not try to diagnose their amp’s problems. All too often, says Hooks, he has heard clients says, “The tubes look fine.” “That doesn’t mean anything,” he says,” You can see whether a tube is lit up or not, but the problem might be the tube, or might be the heater connection, or something else. Just because tubes are lighting up doesn’t mean that they’re working.”

But, just for the sake of argument, let’s say you’re absolutely certain that a tube has gone south. Is there any reason not to simply replace it yourself? That seems simple enough, even for those of us who can’t read a schematic diagram. Preamp tubes are fair game for tinkering, says Hooks, but not the power tubes. “The common tubes in the preamp section are all in the 12A family,” he says. (12AX7, 12AT7, 12 AU7, and so on.) “They each have different characteristics. You can swap those around. That’s kind of a fun way for a guitar player to nerd out and find their own thing. You’re not gonna hurt the amp. You can throw a lower gain tube in the first stage and see if you like it or not. The ECC83 and 7025 are also in the same family. You can try throwing in an old RCA 7025 and you may hear a huge difference. Some people just like thinking they hear something different—like, ‘I can’t really tell, but I think I like it.’ It doesn’t really matter at that point.” But changing your own power tubes? No way, Hooks says. “Let somebody professional do it. Because even if the amp doesn’t have an adjustable bias control, you can still check bias and I always check bias on amps that I work on. No matter what. I don’t recommend doing that on your own. The thing is, if you get a pair of power tubes, and they’re brand new, that doesn’t mean that they’re going to be okay. They need to be tested in the amp that you’ll be putting those tubes into. I’ve seen amps come into the shop that are meant for 6L6 power tubes and they’ve got EL34s in them. Just because a tube fits into a socket doesn’t mean that it’s meant to work there. When you’re dealing with the power-amp section of the circuit, it’s a lot more critical to make sure that you have the right tubes, that the tubes that are running as designed, and that they have the right current running through them. That’s a healthy amp.” -Adam Levy

Photo: Margo Harshman