Quick Hit: ValveTrain PowerTrain Studio 20 Review

An incredibly simple cabinet that adds glowing tube warmth to your digital setup.



Impressive feel and volume for 20 watts. Dead simple to use.



ValveTrain PowerTrain Studio 20


Ease of Use:



With all the advances in guitar technology over the last few years, deciding between analog and digital isn’t an either/or choice. You can have both. ValveTrain’s PowerTrain Studio 20 is an impressively powered cab aimed at adding real tubes to your digital signal chain. Inside the Studio 20 sits a 12AX7 preamp tube and a pair of 6V6 power tubes, which is wrapped in a handwired Class AB setup. Around the front sits a single volume knob that just makes things loud. Real loud.

I used a Fractal Audio Axe-Fx III and a Headrush Pedalboard to give the Studio 20 a workout. Set up couldn’t be any simpler: Just plug in and crank it up. The clarity of the Eminence Copperhead speaker was inspiring and punchy. I dialed up a Vox-style AC30 patch and the high-end breakup and chime came through amazingly well. In most cases, I would turn off the cab sim in the modeler. However, there were a few settings where I preferred “doubling” up on the cabs to create a different EQ curve.

Obviously, the quality of your tones will depend on how dialed in your modeler is. However, even with less-than-perfect presets, the PowerTrain Studio 20 brought out all the harmonic richness and warmth that I look for in any tube amp. Also, don’t be fooled by the 20 watts under the hood. (ValveTrain also makes a 50-watt model.) This cab is loud. I can’t imagine having the volume much past noon even when you’re playing larger clubs. Having some glowing glass right before the sound hits the speaker is a great idea, and if you’re the kind of player who lives in the digital world, the PowerTrain Studio 20 could fool your ears and hands.

Test gear: Schroeder Chopper TL, Fractal Audio Axe-Fx III, Headrush Pedalboard

Flexible filtering options and a vicious fuzz distinguish the Tool bass master’s signature fuzz-wah.

Great quality filters that sound good independently or combined. Retains low end through the filter spectrum. Ability to control wah and switch on fuzz simultaneously. Very solid construction.

Fairly heavy. A bit expensive.


Dunlop JCT95 Justin Chancellor Cry Baby Wah


Options for self-expression through pedals are almost endless these days. It’s almost hard to imagine a sonic void that can’t be filled by a single pedal or some combination of them. But when I told bass-playing colleagues about the new Dunlop Justin Chancellor Cry Baby—which combines wah and fuzz tuned specifically for bass—the reaction was universal curiosity and marvel. It seems Dunlop is scratching an itch bass players have been feeling for quite some time.

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  • Develop a better sense of subdivisions.
  • Understand how to play "over the bar line."
  • Learn to target chord tones in a 12-bar blues.
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Playing in the pocket is the most important thing in music. Just think about how we talk about great music: It's "grooving" or "swinging" or "rocking." Nobody ever says, "I really enjoyed their use of inverted suspended triads," or "their application of large-interval pentatonic sequences was fascinating." So, whether you're playing live or recording, time is everyone's responsibility, and you must develop your ability to play in the pocket.

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