Amped: A Touring Artist's Roadmap to Maintenance
Eric Swanson is a longtime collaborator and pedal-steel/utility man with Israel Nash and has recorded and performed with a number of national and worldwide touring artists. Eric is also a talented amp technician and electrical engineer dedicated to amp/gear design, builds and repairs for his company Swantronics and for Henriksen Amplifiers in Denver, CO.
So you want to take that super sweet beastly beauty of a tube amp on the road so you can show those fire chops and shredder riffs off to the world. It’s been sitting in your practice space and you have it dialed-in for rock n roll sonic purity. But now, you’re going to throw it in the back of a van and drive over every pothole in this big ole world to bring that glorious tone to the masses. What could go wrong?!
In this post, I’ll talk to you about what you can do to prevent problems and, in the inevitable case that something does go wrong, what you can do about it. We’ll bring up some basic concepts but, don’t fret, we’ll avoid math and techno babble as much as possible!
SAFETY WARNING! Tube amps operate at high voltages in order to amplify sound. DO NOT play around with the internal circuitry either while the amp is on OR off. The voltages in some amps can hang around for hours or days and still have the potential to KILL YOU. This is not a joke. If you feel the need to open your amp up, that is a huge red flag and a sign that you need to enlist a qualified technician. This is a serious matter. If your body is used to discharge high voltage to ground there is risk of SERIOUS INJURY OR DEATH.
HELPFUL THINGS TO HAVE
Screwdriver (get one with interchangeable bits, usually <$10 at a hardware store)
Wooden or Plastic Chopsticks (just grab an extra set at the Chinese Buffet where you’re gonna have lunch)
Extra ¼” instrument cables. Short and long
Spare tubes (a whole set is nice, but you can get by with a set of power tubes and a few preamp tubes)
GET OUT OF YOUR OWN WAY
Before we get to that vintage amp of yours, let’s talk about all of the other non-amp things. I see a lot of people attribute behaviors to their amps when the problem is coming from another source. Stop blaming your amp! Check these things first.
Guitar - Buzzes, hum, static, crackling can all come from your guitar. Or no sound at all can come from your guitar. Does the problem go away when you turn your guitar volume down? Does it change when you move the guitar? Silence when you face a certain direction? That’s not your amp, that’s likely the guitar.
Cables - Cables go bad all the time. Especially if they’ve been run over 1,000 times by your road case and twisted in knots during your epic guitar solos. Always carry a spare. Make sure it is actually an instrument cable and not a speaker cable. Yes, that matters!
Pedal Boards - This is a minefield of potential problems with all of those cables, connectors, power supplies, knobs and switches. Wiggle those cables and turn those knobs. If there’s noise or intermittency in any of these things, address that before you head out to the gig.
Batteries - Are you one of those weirdos with an active on-board preamp? If you’re experiencing weird distortion, loss of clarity or headroom, that could be because of your dying battery. Change that battery, baby!
Did you do all of these things and your sound still sucks? Try practicing! Kidding… but seriously, don’t forget to practice. If you’ve done your due diligence and are still having issues, we can now talk about your amp.
Tubes are the first stop in troubleshooting a tube amp problem. In most tube amps, they are used at every stage and do a variety of jobs. The fragile nature of tubes introduces a number of potential problems for the touring guitarist. They’re made of glass, have internal delicate electrodes, and operate at high voltages and temperatures. Consider them consumable components, kind of like the tires on your car: Wear and tear over time diminishes performance and every now and then you might get a nail in the tire or have a blowout. Tubes have analogous pitfalls.
If your tubes are easy to access, you can do a quick visual test to make sure they are all lighting up (faint orange glow) and not making any crazy sparks or flashes. Flashes or sparks are always a bad sign and if you see these, turn the amp off immediately.
You can also turn the volume up a bit on the amp with nothing in the input and tap the tubes gently with a chopstick or pencil. If any of them make obnoxious noises, there’s a good chance the tube is microphonic and is adding that noise into your signal path.
Preamp tubes are easy enough to change on your own. If you’re technically inclined, familiarize yourself with what each tube in an amp does. Then if you experience a problem in just one part of the circuit (channel 1 is noisy or the tremolo isn’t working, for instance) you can try swapping that particular tube to see if it solves the problem. Take care to make sure the pins of the tube are lined up correctly. I’d leave the power tubes alone here as a mistake in this area can be costly. If power tubes are sensitive to touch, I’d recommend having a professional take a look.
Another simple thing you can do is to have the tubes tested. A lot of repair shops will do this for free or a small fee, especially if you’re an existing customer. It pays to befriend your local amp tech! We aren’t all salty dogs. You’ll want to gently remove your tubes one at a time and number them with a Sharpie (it won’t hurt the tube) to let you know where that tube came from. Make a diagram of the tube layout if there isn’t one on the amp or if it has a more complex layout than a straight line. Wrap them up in bubble wrap or tissue and take them by a tube shop. You might want to call in advance to make sure they have the time to do this. This is also a good opportunity to check that all the tubes are correct. It’s a common mistake to use a 12AX7 where a 12AT7 should be, etc.
SPEAKERS AND CABINETS
While you’re checking out the tubes, take a second to examine the speakers, speaker connectors, and cabinet. Check the connections to each speaker and make sure that they are snug or, if soldered to the terminals, that the solder joint is solid and not cracked or broken. Loose speaker connections can lead to disastrous results and expensive repairs.
Look at how the speakers are mounted to the speaker baffle. If those screws or nuts are loose, it’s a good idea to tighten them down. Be careful not to overtighten; a little tighter than hand tight is good enough. But you want them to be secure so they don’t rattle around even more in the back of your van.
Amps have wildly varying cabinet construction methods but if your speaker cabinet uses screws to secure any part of it, it’s easy enough to go over them and make sure they’re tight. Again, a little more than hand tight is usually good enough.
A really powerful tool in solving amp problems is having a logical method of troubleshooting. A lot of nebulous words get thrown around when talking about amps, but there is no magic as to how they work. Taking the time to understand your gear at a basic level will help you in the long run. Your job is to whittle down and rule out all the potential sources of the problem until there is one left. Logic is your friend here. If something is easily reproducible by a consistent action, that is a huge sign that you are headed in the right direction. Or if the problem happens when you do one thing but not another, that is another big clue. Investigate, isolate, eliminate, and repeat until you home in on the source of the problem.
If any of these things occur, take your amp to a qualified tech.
Seriously loud buzzing or popping that is not affected by the volume knob of the amp. This is a common sign of a failure in the power section of the amp. Do not continue playing on the amp. Turn it off and take it to a tech.
Blowing fuses is also a sign of a more serious issue. Don’t put a bigger fuse in. You’re just asking for trouble and an even more expensive repair.
Smoke! If your amp starts melting things other than faces, it’s time to shut it down and take it to a tech.
Shocks! If your amp is producing sparks or if you are getting shocked when you touch the amp, that is a big red flag. Turn it off immediately and get it to the doctor.
Strange tube behavior like flashing or glowing bright red also means there’s something wrong.
With online shopping supplanting brick and mortar stores, it’s increasingly difficult to find some of the parts you might need to get your amp running again during a tour. But there are still resources to get help when you’re far away from home.
Ask local friends who they take their amp to.
The venue might employ a tech or know of one.
Backline companies usually retain some sort of tech to maintain their gear.
A lot of guitar repair folks have some tubes or amp parts on hand too. They also usually know a few amp techs in town.
Most amp techs will have the most common tubes in stock and will usually sell them to you.
Local guitar stores generally have some tubes on hand. I find the bigger stores have a more limited selection but your mileage may vary.
I get a lot of referral work at Swantronics, especially from touring bands, and I almost always give them favorable treatment when I can. Having toured myself for so long, I know how hard it can be to get a problem solved on the road. Kindness and patience can go a long way in these scenarios!
I really hope this basic guide can help equip you with some tools, methods, troubleshooting to get and keep your amp roaring and road-ready! In the future, I’d like to dive into the deep end on some basic concepts that will expand on some of the ideas I’ve laid out above. Looking forward to seeing you then. Thanks for reading!