If you’ve owned a tube amp for pretty much any amount of time, you’ve been there: Your amp starts making noise—probably at the worst possible moment, whether onstage, in the studio, at rehearsal, or when you just really want to play—and you don’t know what to do. Maybe you keep it cool, but maybe you panic: Is my amp broken for good? Is this going to cost me hundreds of dollars? Fortunately, there are a few basic things you can check before you call your amp tech in a frenzy.
Ultimately, an all-tube guitar amp is actually a very durable device. But it’s important to remember that these amps need maintenance and have parts that are going to need to be replaced over the course of their lives—and tubes are the most likely place to check when you’re having a problem.
Many vacuum tubes are “military grade,” which means they can withstand shock, vibration, humidity, temperature, and many other harsh conditions. That doesn’t mean they are fail-proof, though. So, when your amp is making noise, here are some ways to check out your tubes.
Look
Do a visual inspection. Are your amp’s tubes bright and shiny, or do they look weathered and dirty? If they look old, they may be old. This doesn’t have to be a sign of something wrong, but tubes wear out like lightbulbs—they work until they don’t. I usually say power tubes have a two- to five-year lifespan (for professionals, it’s more like six months to two years). Preamp tubes have more like a five- to 20-year life. They can function longer but start to get problematic before they just die.
Look at what’s going on inside. Is the clear part of the glass still clear? If there is a smoky look on the inside of the glass, that is a sign of heavy wear. Look at the shiny mirror-looking part; that is the getter flashing. It should look bright, though sometimes there is a little fuzziness along the edges. If it is getting smoky, then the tube is tired. And if it has gone completely white, the tube is toast.
The last visual is best done in darkness. Look for the heater element inside. It is a wire in the very center of the tube structure that glows red when operating. Don’t worry about what shape it is, how much you can see it, or if it looks exactly like the other tubes. If it is glowing, it’s good; if it is dark in there, it’s toast.
In his final PG column, the amp maker to the stars teaches you how to troubleshoot your guitar’s loudhailer if it’s raising a sonic ruckus.
Listen
Let’s move on to audible diagnostics. The amp works but is making extraneous noises. The first thing to do is unplug the guitar cable from the input of the amp, so nothing is plugged in, the amp is fully on, and the tone controls, volume, and master (if applicable) are full on. What noises do you hear? If it is silent with a tiny little bit of background noise, that is as good as a guitar amp gets.
Are you hearing an electronic, almost morse-code sound? A common modern problem is RF (radio frequency) noise from routers, cell phones, and transmission towers. It is not the amp and there is nothing to fix, but if you try moving the amp around the room or building, you may find a quieter place.
Is the amp making a constant “shhhhh” sound? Does it get louder if you turn the volume knob up? That is thermionic emission, the noise of electrons flowing. It is a byproduct of gain. Low-gain amps have less, and high-gain amps suffer greatly. Some tubes can add to this, so if you replace the first couple tubes in the signal path and it helps drop the noise floor, then keep the noisy ones for less critical positions.
Is the amp sitting there doing the snap-crackle-and-pop thing? This can be a tube issue, but most of the time it is a component issue inside. If you have a known good tube, you can replace the tubes one at a time, seeing if the noise changes. If you find that it was a tube, that tube is toast, so don’t use it as a spare.
Now, let’s talk about microphonics. Because of the amount of gain we have in guitar amps, microphonic tubes can be problematic. Start turning the amp volume/gain all the way up. If you get a howl, like with an open microphone, you have a microphonic tube. If it is still behaving but you can tap on the amp and get a sound like tapping on a microphone, that can be acceptable.
Finding the Cause
There are multiple tubes in an amp, so let’s find the root of the noise. The first thing is tap testing. The best tool is a pencil with an eraser. One by one, tap on the tubes with the amp on and turned up. If you get a significant microphonic sound from one, it should be swapped out with a quieter one. Now, this is the thing: A little bit of microphonics is normal, so it will take a little getting to know your amp to learn what is acceptable or not. Certain brands/models of tubes are better than others, so just because it’s new doesn’t mean it’s better or even good. As you go down the line of the signal chain, the gain is less, so you are looking for slight noises. Once you get to the power tubes, they can be microphonic, but they don’t howl like a preamp tube. They make a thud sound when tapped.
The other thing we’re looking for with this tap testing is rattling. Again, there is a certain level of acceptable rattle. But if you can hear it through the speaker, that’s unacceptable. If you have power tubes that rattle, this sometimes does not come through the speaker, but you can hear it when playing the amp at lower levels. If that bothers you, then they need to be replaced even though they’re functioning properly.
The last diagnostic is pulling the preamp tubes (not the power or rectifier tubes). Starting with the first tubes in the signal chain, pull them out one at a time and listen to see if the noise goes away. If you pull a tube and the noise disappears, then either that tube is the culprit, or your problem lies in that part of the circuit.
If you’re looking for a quick fix to get you through your gig or session and you narrow your problem down to a tube, go ahead and swap it out. If your amp is fixed bias, you may still need to head to your tech tomorrow and have it biased, but you’ll get your work done today. And when in doubt, replace your old tubes. If it turns out that wasn't the issue, you now have good spares for when a tube does eventually give you problems.
Question:What pedal doesn't exist now that you hope gets built in the next year?
Guest Picker - Penelope StevensMotherhood, Penny & the Pits
Photo by Brad Allen
A: I’m a synth player before a guitarist, and for years I’ve been trying to figure out a way to play my synths through my guitar … or my guitar through my synths? I know there are pedals that can make your guitar sound like a synth, even some that can emulate particular models, but I want a pedal that I can connect to any synth, and it can feed whatever patch I’ve built through my chain. I have a Volca Keys that makes absolutely GNARLY tones, and for a while I was trying to figure out a way to have it in my pedalboard as an effect. Alas, this is quite beyond my skillset—I’m no electrical engineer—but the dream has never died. Imagine being able to shape your guitar tone with as many possibilities as on an analog synth! Can somebody make me this pedal please?
Obsession: When I’m not touring, I’m a cocktail bartender. (PLEASE don’t call me a mixologist.) My current obsession is this margarita riff I’ve been working on: tequila blanco, amaretto, lime, and prickly pear shrub. I’m drinking this little number more than I should probably admit, especially as we fight a heat wave in eastern Canada. I’ve been making cocktails to go along with each song on my new album, and filming tutorials for each one on Instagram. The prickly pear margarita will be making an appearance soon!
Reader of the Month - Jin J. X
A: The out-of-production Boss VB-2. I absolutely love chorus and vibrato. I also love Boss. While I appreciate the CE-2w and absolutely love the upgrade/update, I just haven’t been able to connect with its counterpart, the VB-2w. I’ve tried multiple times to buy that pedal but to no avail. The Behringer UV-300 is analog and sounds absolutely perfect, though I’ve found that every single one I’ve bought over the years has a switch failure, and many modders can’t really work with them. Also, there are other great vibrato pedals, though without the “rise” function of the VB-2, I don’t find them as useful. I’ve heard the BYOC folks make one, though they seem to sell very quickly. I hope Boss, or someone, makes a true-blue VB-2-style pedal, with the right analog chip, that is built with solid components.
Obsession: Country-style guitar. Fifteen years ago, I bought a DVD called 50 Licks Country Style featuring Troy Dexter. After all these years, I finally pulled it out of the plastic and have begun trying to work those up. In many ways, the licks revolve around dominant 7 chords, so, in some ways, these country licks sound like jazz licks in the bridge position. It’s like a two-for-one special learning them. I also recently released an Afro-futurist/country album earlier this year called The Barefoot, Pregnant, Neck Beard, Marital Bed String Band, so I’ve been playing and promoting that record and putting my country licks to good use.
Brett Petrusek - Director of Advertising
A: I’d love a Boss Waza Craft Dimension C with a mix control knob, or better yet a Waza Craft reissue of the Digital Dimension with expanded tonal range, better filtering, fancy high-quality buffer, and with that ultra-low noise floor.
Obsession: Auditioning stereo modulation pedals. I use pedals like this in my live rig to split out in front of two big amps to expand the stereo field. I like the option of being able to keep it subtle and having easy access right on my pedalboard (old-school). It’s an art form to find modulation or doubler pedals that will do this into the front end of high-gain amps without a lot of hiss. I am currently digging the Mr. Black DoubleTracker Stereo; it can get insanely wide (especially in the effects loop). Maybe Keeley will make a stereo 30 ms in their new folded aluminum enclosures … I bet their fanbase would go nuts!
Nick Millevoi - Senior Editor
A: I’ve spent years longing for a pedal that captures the unique sonic capabilities of the Lexicon Prime Time. The Soundtoys PrimalTap plugin does an excellent job for working at home, but I dream of making those warm, ethereal sounds live (and the pricey rack unit itself isn’t practical for most of us). The Prime Time’s double delay lines with lo-fi-enhancing multiply knob sounds truly unique among delay units (dig it, Daniel Lanois enthusiasts), and its hip primary color knobs demand pedalboard real estate!
Obsession: I just caught Tommy James & the Shondells live and was blown away. Over the course of a relentlessly hit-laden set list—seriously, it was one after another: “Crystal Blue Persuasion,” “Mony Mony,” “Crimson and Clover,” “I Think We’re Alone Now,” “Draggin’ the Line,” and on and on—Tommy’s voice was in the finest form, driven by a powerful, heavy-grooving band. Go see ’em if you can!
Linkin Park went on hiatus for seven years after lead vocalist Chester Bennington’s death in 2017, but last September, the band announced that they were returning with new music and a new lineup—including vocalist Emily Armstrong and drummer Colin Brittain. A new album, From Zero, was released in November 2024, followed by the single “Up From the Bottom” earlier this year, and this summer, the band tore off on an international arena and stadium comeback tour. Founding lead guitarist Brad Delson is still a creative member of the band, but has elected to step back from touring. And so on the road, Alex Feder takes his place alongside founding guitarist/vocalist/keyboardist Mike Shinoda, DJ Joe Hahn, and bassist Dave Farrell.
PG’s Chris Kies headed to downtown Nashville’s Bridgestone Arena to meet up with Mike Shinoda, plus techs Mark, Ben, and Tracy, to learn how the band pulled off their much-anticipated gigs this year.
This is Shinoda’s “workhorse” Strat, a longtime trusted pal that’s featured on songs like “What I’ve Done.” There have been plenty of times when Shinoda gets bored on tour, and at one point, he started painting his guitars to keep himself occupied—including this Strat.
Painted PRS
This PRS is from the band’s Meteora-era, a definitive instrument in the early years of the band. Again, the guitar’s aesthetic customizations were executed by Shinoda himself, with ink markers, spray paint, and a paint pen—plus some custom “etchings” on the fretboard. This and his other guitars are outfitted with custom Kill Spencer straps.
Blackout
This black Gibson SG came into the picture around Linkin Park’s third record, 2007’s Minutes to Midnight.
Empty Spaces
With new vocalist Armstrong’s voice filling a different spot in the band’s sound, Shinoda has adjusted some of his tunings and playing. This Fender Blacktop Baritone Telecaster helps give Armstrong’s voice space and keeps everyone in their sweet spots, frequency-wise.
Hybrid Theory Heavy
This 2008 PRS Custom 24 is a replica of Delson’s Hybrid Theory-era PRS, and sports Paul Reed Smith’s autograph on the back. It lives in drop C-sharp tuning, and if Delson is playing it, it’s loaded with D’Addario NYXLs (.010-.052). When Feder’s at the wheel, he goes for heavier top strings mixed with Delson’s packs, for a gauge range of .054-.044-.032-.017-.013-.010.
Another PRS, finished in grey and tuned to drop D sharp, features the Minutes to Midnight logo and gets brought out for “One Step Closer.” A sunburst PRS DC3 is equipped with even heavier strings for a drop A tuning: A-E-A-D-G-B.
’61 Standard
This Fender Custom Shop Rory Gallagher Stratocaster has become a staple of the live show. It’s part of a set of three that were created for Delson, designed and relic’d to mimic a 1961 Standard Stratocaster. It stays in drop D, with Delson’s standard .010-.052 strings. He uses .72mm Dunlop picks, while Feder uses slightly heavier .88mm picks.
Mike Shinoda, Brad Delson, and Alex Feder’s Rack Systems
Delson’s rig (used by touring member Alex Feder) lives on the left side of this rack, while Shinoda’s takes up the right. They both include a Radial KL-8, two Radial JX44s, two Shure AD4Qs, and two Fractal Axe-Fx III units. Shinoda’s setup also includes two Electro-Harmonix HOG2 pedals. The fractals use IRs that were captured by old FOH engineer Pooch, using a Randall cabinet.
MIDI handles all of the changes for the show, though there’s a Fractal FC-12 foot controller on hand in case of emergency for manual switching. Fred Carlton of Nerdmatics, who built the Linkin Park rig for this 2024-2025 run promoting From Zero, shared some more information with us after filming: “The backline gear consists of about 11 computers running Ableton, all receiving locator information from the main playback computers. We maintain redundant computer systems for Joe Hahn’s DJ rig, Mike Shinoda’s keyboard rig, the Audio FX rig, and the Playback system. Single-computer setups are used for both guitar rigs and the bass rig, as these stations only send MIDI patch changes and do not handle audio. Additional single-computer systems are in place at Monitor World, FOH, and within the Visual department.
Each station carries an updated timeline of the show, allowing techs to insert automation data such as MIDI or timecode to control their systems. Once changes are made to the main Ableton session, we distribute updated .ALS files to all departments, enabling them to integrate their specific data into the new timeline. This workflow allows us to implement changes quickly while keeping all departments aligned. Having separate computers also gives each tech the ability to test their own system independently. In the event of losing RTP network connectivity, they can punt the show locally without relying on external automation.”
Sharpened with Precision
This Fender Custom Shop Precision bass is Dave Farrell’s go-to, his tech Tracy explains. It’s tuned to either drop D or standard, and Farrell uses Ernie Ball Bass Hybrid Slinky strings (.045-.105) with Dunlop .88mm picks.
Ernie Ball Basher
This beloved Ernie Ball Music Man StringRay, with active electronics and neck-through construction, is the second-most used bass in the rack, and comes out for hits like “Papercut” and “In the End.” It’s tuned to drop C-sharp.
Mum Knows Best
Though his other StingRay gets more play, this is the original item, which Farrell’s mother bought for him. It gets tapped for tracks “Somewhere I Belong” and “Faint.”
Dave Farrell’s Rack
Along with the same accoutrements (Radial KL 8 and JX 44, Shure AD4Q), Farrell also uses a pair of Fractal Axe-Fx IIIs, and runs three signals—one of an Ampeg SVT model, a Marshall JMP-1 model, and a clean direct signal, run through emulations of two Ampeg 4x10 speaker cabinets—to front of house, which can mix and match between the three as needed.
Discover the magic of tone with the latest pedals! From the versatile Brothers AM to the warm Keeley Manis Overdrive, each offers unique sonic possibilities. Ready to elevate your sound? Dive into the Eventide H90's powerhouse effects or the compact CHO-mini's rich chorus. Which pedal will inspire your next masterpiece?
CHASE BLISS Brothers AM
A faithful tribute to the Analog Man King of Tone, the Brothers AM offers dual multi‑mode gain channels—boost, overdrive, or distortion—with intuitive controls, live tweakability, and four onboard custom presets. It adds a bonus treble‑booster circuit inspired by the Beano Boost, giving you extra bite and clarity. Fully MIDI, expression, and CV‑controllable, this pedal lets you save tones and stack effects while preserving the warm, transparent character of the original.
The Keeley MANIS Overdrive is a bold evolution of the mythical transparent drive, blending NOS germanium transistors and diodes for unmatched warmth, compression, and grit. With switchable voicings and dynamic touch response, it’s a tone-sculpting weapon built for players who demand both clarity and rich harmonic character in one pedal.
Eventide’s flagship H90 Harmonizer is a powerhouse multi-effects pedal. It features 70 effect algorithms, including reverb, delay, pitch shifting, modulation, and distortion, plus hundreds of curated programs. With comprehensive I/O and flexible routing, the H90 is built to be the heart of your rig, on stage or in the studio.
The Amp Academy Stomp is the latest in amp modeling from NUX. Included are several legacy amps, effects, Bluetooth with an app, workflow features, and more. Most importantly, the Amp Academy Stomp includes Image, which loads NAM profiles into the Amp Academy Stomp and, with black-box algorithms, accurately reproduces the dynamics and responsiveness of any amp profile loaded into the pedal.
The pocket-sized and feature-packed CHO-mini pedal delivers an outstanding selection of chorus tones at a budget-friendly price. With a selection of three curated and timeless chorus effects, the CHO-mini delivers a wealth of sonic possibilities in mono or spacious stereo imaging. Includes tap-tempo, true or buffered bypass, metal housing. Available from Osiamo.
The Fuhrmann Echoes pedal is a versatile delay unit, offering digital, modulated, and analog modes. It provides clear, modulated, or degrading (analog-like) delay repetitions, adjustable with a low-pass-filter control. Featuring tap tempo and two rhythmic subdivisions, this compact pedal delivers up when one delay is not enough.
Batverb is the stereo reverb that dreams are made of. Less of a room simulator and more of a tail-generating pedal, Batverb is an instrument in its own right. Batverb sings in any signal chain, with dedicated controls for suboctaves and overtones, saturation, ducking behavior, and more.
The Ampero II is the latest addition to the Ampero series, a second-generation multi-effects processor that brilliantly combines the iconic stage control of the original Ampero with the power of a new triple-core digital audio processing platform. Plus, a larger, sharper 5-inch dynamic touchscreen and newly designed system UI for smoother, and more intuitive interaction. All while maintaining the compact and lightweight design of the Ampero Series.
The Fuhrmann Stellar Stereo Reverb pedal delivers a broad range of reverbs, from short early reflections to long, floating tails. Users can seamlessly transition between nine stored reverb scenes with no noticeable delay. Intuitive controls allow for precise adjustments, making it a powerful and user-friendly addition for diverse sonic needs.
The DoubleTracker Stereo delivers lush, organic stereo doubling with adjustable delay, pitch, and spread. Featuring dual isolated paths, intuitive controls, and unique SYNC/COMP modes, it adds depth and dimension to any instrument—perfect for guitar, bass, keys, vocals, and studio work. It’s not chorus. It’s Double Tracking.
The Rock N Roll Relics Stinger overdrive has all the mojo of classic, yellow drive pedals, but with tonal refinements to bring it to the modern age. We use NOS construction, as you’ll come to expect with the Stinger Series, which gives it that authentic, ear-pleasing tone we all want.
The prolific Australian guitarist brought his mastery to east Nashville, where we got a look at the gear he’s trusting overseas.
Adam Miller has been compared to plenty of his most sacred influences—Tommy Emmanuel, Chet Atkins, Charlie Hunter, Bill Frissell—but he’s certainly carved a path of his own. This year alone, he’s released three records and undertook a U.S. tour to bring his delightful mix of jazz, groove, and beyond to eager listeners.
Before his show at the Underdog in east Nashville, Miller took some time to show PG’s Chris Kies around his trusted tools for international touring, including a gorgeous custom Huber electric, a Collings acoustic, and some key items on loan.
Calling a Huber
This custom-built Huber electric, by German luthier Nik Huber, was crafted over the last five years, working in elements of Miller’s previous Huber and several other designs. It has a heavily chambered mahogany back and redwood top, bolt-on maple neck, rosewood fretboard, trapeze tailpiece, and nylon saddles, plus Kloppmann Electrics mini humbuckers and a single 250k volume pot, which rolls off for a jazzy archtop sound. Miller strings it with D’Addario NYXLs (.011–.049s).
Borrowed Bari
Since Miller can’t bring all his favorite instruments on tour, he often borrows guitars from local friends and fans on tour, like this baritone Novo Serus J.
Collings Calling
Miller bought this Collings acoustic at Gladesville Guitar Factory, just outside Sydney, about 10 years ago. He runs it with a Seymour Duncan Wavelength duo pickup system, but swapped out the kit’s undersaddle piece for soundboard transducers and modified “the circuit so they’re at a crossover, so you’re only hearing the bottom end of them and all the top end’s coming from the condenser mic.” He uses D’Addario Nickel Bronze (.012–0.53s) on his acoustic.
Can I Bum a Studio Sig?
Miller has been a Two-Rock devotee since 2007, and on one of his first trips to the U.S., he visited the factory and picked one up. He doesn’t travel with his unit, so he borrowed this one from Nashville legend Cory Congilio. For Miller, an amp is the soundboard for an electric guitar; if he doesn’t have a Two-Rock, he struggles.
Adam Miller’s Pedalboard
Miller’s Collings runs into a Grace Design ALiX preamp, which helps him fine-tune his EQ and level out pickups with varying output when he switches instruments. For reverb, sometimes he’ll tap the Strymon Flint, but often he’ll let the front of house weave it in.
Aside from the ALiX and Flint, Miller relies on a Vemuram Jan Ray, Free the Tone SOV-2 Overdrive, Chase Bliss Mood, and Line 6 DL4 Mk II.
Miller’s Collings runs into a Grace Design ALiX preamp, which helps him fine-tune his EQ and level out pickups with varying output when he switches instruments. For reverb, sometimes he’ll tap the 