Two Notes Audio Engineering is best known for their digital DynIR cabinet modeling technology. This tech is the backbone of the company’s Torpedo load boxes and cabinet simulators, as well as cab simulations used by Mesa, Victory, and others. But the new ReVolt Guitar amp simulator pedal is a departure. It’s a tube-driven, 3-channel preamp with analog cabinet emulation that comes in a solid, compact 7" x 4.5" x 3" stompbox. The ReVolt is intuitive, too. If you know how to twist the knobs on your amp to get a sound you like, you’ll fare well with the ReVolt Guitar. There’s no menu diving or secondary footswitches or knob functions. It’s a true WYSIWYG device.
The ReVolt Guitar uses a 12AX7/ECC83 preamp tube in triode mode running at 200 volts as an output-stage cathode follower—a tried and true amp design that adds some of the warmth and compression digital amp modelers can miss. With a built-in cabinet emulation and balanced XLR line output, it’s a powerful, economical, and very space-efficient solution for the stage and studio.
California Cleans and Metal Means
Each of ReVolt’s three channels—clean, crunch, and lead—feature independent gain and volume controls. For EQ, the clean channel has bass and treble controls, while the crunch and lead channels share a 3-band EQ with mid control. A single boost output level knob rounds out the upper panel controls. Each channel is activated by a footswitch, and the unit is bypassed by pressing the clean and crunch channel footswitches simultaneously.
The clean channel, modeled on a Bassman 100, is classic Fender stuff—glassy top end, scooped mids, and round lows. It has headroom for days—maybe even too much for some players. It doesn’t break up at high gain, but imparts mild compression that feels like tube rectifier sag. With the tone controls at noon, it’s boomy and bright, and, generally, I needed to run those controls at more modest levels to get the right balance of warmth and sparkle.
The crunch channel offers a broad drive range. Below 11 o’clock, the sounds are old-school plexi, complete with grinding and chunky Super Lead-style tones. Beyond the halfway mark on the gain control, you’ll start to hear hot-rodded Marshall tones with husky midrange and tight distortion. Some preamps miss the mark when approximating the toothy upper mids that are a Marshall signature. But Two Notes approximated this characteristic well. Paired with a low-gain drive pedal, the output takes on an intensity and warm thickness that avoids being shrill. And it’s reassuring to know you can drive the ReVolt’s front end aggressively without sacrificing sweetness.The 3-band EQ, with crossover at 100 Hz, 750 Hz and 1.5 kHz, makes it easy to fine tune as you move between screaming and merely heavy.
The lead channel is inspired by the Soldano SLO-100, and it has much of the heavy low end, scooped midrange, and rich high harmonics that are Soldano hallmarks. Lower gain settings (below 10 o’clock) yield tight, responsive overdrive. Like the crunch channel, the lead channel is reactive to gain pedals, and placing a low gain overdrive or boost before the input adds similar thickness. It also sounds articulate through its gain range and almost never muddled or fizzy.
Staying Self-Contained
Though the ReVolt Guitar responds well to drive pedals, you don’t necessarily need one. It comes with a boost that’s activated by pressing a footswitch and is shaped by the boost knob. The boost is inserted in front of the preamp.On the clean channel, it helps generate classic Tube Screamer-meets-Fender sounds and a very useful range of low- to mid-overdrive tones. But I was less impressed with how the boost paired with the crunch and lead channels. In both cases, using the boost came at the cost of the inherent warmth in both channels, lending an edgy feel. Some players may find good use for this tonality, but I found the warmer side of crunch and lead more useful. The good news is that some of this issue can be remedied with a tweak to the rangy 3-band EQ. And while I didn’t find the ReVolt’s boost a best match for crunch and lead, both channels sounded good with external drive units, including a Barber Burn Unit, Greer Lightspeed, and a good klone. I also had success using the mono effects send-and-return for time-based effects, and pedal integration via that method is a breeze.
The cab-sim mini-switch on the front panel enables an internal cabinet simulation, which can be routed via the balanced XLR output as well as the headphone output. The ReVolt Guitar is bundled with the Wall of Sound cabinet collection, which utilizes Two Notes’ DynIR algorithms. You’ll need to experiment to find out which cabinet emulations work best with each channel. But the algorithms give you a lot of tone-shaping flexibility—particularly when working in a DAW.The ReVolt Guitar is MIDI-enabled, by the way.
You can also use a 4-cable method, which is enabled by a mini-switch on the front panel, to utilize an effects loop amp and create four discrete channels. In this mode, when a ReVolt channel is activated, the signal is sent to your amplifier’s effects return, bypassing your amplifier preamp so you can pair the ReVolt directly with your amplifier’s power amp—subtracting your own preamp colors from the blend.
The Verdict
The ReVolt Guitar’s ease of use and intuitive interface make it quick and easy to integrate into a creative flow. It delivers tube-amp-like response and dynamics as well the natural compression that a tube amp gives you as you advance the gain. You sense warmth, you hear that slight buzz as the front end of the amplifier overdrives, and feel real, interactive, push and pull. And you can access all these elements while using the ReVolt at low volume with your DAW. This combination of attributes results in a lot of exciting and practical amp tones that I don’t always hear and feel in DSP-based amp sims. This well-thought-out and well-executed design makes ReVolt Guitar a great hybrid alternative to those all-DSP compact amp solutions.
For DAW recording, bedroom players, and gigging, the ReVolt is a solid choice—especially if you like a little hair and aggression in your tone. The bundled Wall of Sound software has a dizzying array of options and ups the tonal versatility. Used together, the ReVolt and Wall of Sound offer the best of analog and digital modeling.
Vox’s Valvenergy Tone Sculptor
I spent a day workshopping ideas in my studio using just the Vox Valvenergy Smooth Impact compressor and Tone Sculptor EQ, and a dash of amp tremolo and reverb to taste. In the process, I produced more arresting sounds than I had heard from my guitars in many days. There were radical direct-to-desk-style Jimmy Page/Beatles distortion tones, sun-sized, cosmic electric 12-string, Bakersfield twang that could burn through crude, and many other sweet and nasty colors. Most decent EQ and compressor combinations can achieve variations on all those themes. But the Smooth Impact and Tone Sculptor also reveal interesting personalities in unexpected places.
The individuality and energy in the Vox Valvenergy pedals is attributable, in part, to the Nutube vacuum tube used in the circuit. Though it looks little like a vacuum tube as most guitarists know them, the thin, wafer-like Nutube is, in fact, a real vacuum tube like those used in fluorescent displays. Fluorescent display tubes have limitations. A maximum operating voltage of around 40 volts means they aren’t useful for bigger power tube applications like a 6L6, which has an operating voltage of about 400 volts. But it can work quite well as a preamp tube in concert with an op amp power section, which is how the Nutube is used in the new Valvenergy pedals, as well as older Vox products like the Vox MV50 and Superbeetle amps.
Valvenergy Tone Sculptor
When you think about “cinematic” effects, you likely imagine big reverb or modulation sounds that create a vivid picture and feeling of space or motion. But narrow, hyper-focused EQ profiles can evoke very different and equally powerful images. Radical EQ settings can add aggression, claustrophobic intimacy, and stark, explosive dark-and-light contrasts more evocative of Hitchcock’s Psycho than Ridley Scott’s Blade Runner.
Any of these moods can be summoned from the Valvenergy Tone Sculptor. Six sliders cut or boost 10 dB frequency bands spanning 100 Hz to 5.6 kHz. A seventh slider cuts or boosts the master output by 12 dB. This platter of options might not sound like much. But you can use these seven controls together to very specific ends.
“Radical EQ settings can add aggression, near-claustrophobic intimacy, and stark, explosive dark-and-light contrasts.”
For example, bumping the high-midrange and the master output produces narrow cocked-wah-like filter sounds with enough push to produce extra amp overdrive—effectively turning the Tone Sculptor into a buzzy, almost fuzz-like filter effect. But unlike a wah, you can carefully scoop high end or add a spoonful of bass to blunt harsh frequencies or give the tone a bit more weight. You can also broaden the palette of an amp/guitar pairing. I matched a particularly trebly Jazzmaster bridge pickup with a very hot and toppy Vox AC15-flavored amp for this test—a recipe that can be spiky on the best days. But with the Tone Sculptor in the line, I could utilize the same sharp, fuzzy, and filtered Mick Ronson wah tones while shaving some of the most piercing frequencies.
EQ pedals exist on many points along the cost spectrum. And at $219, the Tone Sculptor lives on the high side of the affordable range. Does it offer something less expensive models can’t deliver? Well, for one thing, I found it relatively quiet, which is nice whether you’re shaping toppy high-contrast effects or performing more surgical adjustments. And the sliders feel nuanced and nicely tapered rather than like a dull axe with a few basic frequency notches. But in many situations I also liked the color imparted by the circuit—generated, presumably, by the Nutube. “Color,” in audio terms, is a broad and subjective thing, and one should not necessarily expect the warm, tube-y glow of a vintage tube Pultec. Still, the Tone Sculptor has many forgiving, flattering qualities—typical of studio EQs—that enable fine tuning and experimentation with more radical and creative applications of the effect.
Valvenergy Smooth Impact
As with the Tone Sculptor, the Smooth Impact’s use of Nutube engenders certain expectations. It’s easy to surmise that because Smooth Impact has a vacuum tube in the circuit that it will behave like a little Teletronix LA-2A leveling amplifier. That’s a big ask for a $219 stompbox. On the other hand, the Smooth Impact exhibits some appealing characteristics of studio tube compression. At lower compression levels, it works well as a thickening agent—adding mass without much additional noise. And at higher compression levels it can sound snappy, crisp, and tight without feeling like you’ve bled every trace of overtone from your signal.
The Smooth Impact’s controls aren’t totally atypical. But because it lacks some familiar features like variable attack and release, yet is more complicated than a 1-knob DynaComp, you have to trust your ear to navigate interactions among the controls. The most unfamiliar of these is the 3-way vintage/natural/sag toggle. The first two are defined by preset attack and release settings: Vintage is slow attack and long release, and natural is the opposite. The sag mode’s compression is more like what you get from tube saturation, and it’s useful for adding thickness and complexity to a thin amp tone at modest compression levels.
Though the vintage and natural modes certainly have a different feel, they don’t always sound worlds apart. And like the sag mode, the thing they have in common is the way they enrich lifeless amp output at low to medium compression, with a bit of grind from the tube gain and a little extra makeup gain from the output. At the most aggressive settings, the tube gain can get a little crispy. And really crushing the compression can flatline your tone without adding much in the way of extra sustain. These are limitations common to many compressors with similar features. But unless I was chasing very ultra-snappy Prince and Nile Rodgers fast-funk caricatures, I enjoyed the Smooth Impact most in its in-between ranges, where mass, mild, harmonious drive, and low noise showcase the pedal’s sometimes studio-like personality.
Boss’ firstWaza Tube Amp Expander, built with an integrated power amp that enables boosted signal as well as attenuated sounds, was and remains the OX’s main competition. Both products have copious merits but, at $1,299 (Boss) and $1,499 (Universal Audio), each is expensive. And while both units are relatively compact, they aren’t gear most folks casually toss in a backpack on the way out the door. The new Waza Tube Expander Core, however, just might be. And though it sacrifices some refinements for smaller size, its much-more accessible price and strong, streamlined fundamental capabilities make it a load-box alternative that could sway skeptics.
Micro Manager
The TAE Core is around 7 1/2" wide, just over 7 " long, and fewer than 4 " tall, including the rubber feet. That’s about half the width of an original TAE or OX. The practical upside of this size reduction is obvious and will probably compel a lot of players to use the unit in situations in which they’d leave a full-size TAE at home. The streamlined design is another source of comfort. With just five knobs on its face, the TAE Core has fewer controls and is easier to use than many stompboxes. In fact, the most complicated part of integrating the TAE Core to your rig might be downloading the necessary drivers and related apps.
Connectivity is straightforward, though there are some limitations. You can use TAE Core wirelessly with an iOS or Windows tablet or smartphone, as long as you have the BT-DUAL adaptor (which is not included and sets you back around 40 bucks). However, while desktop computers recognize the TAE Core as a Bluetooth-enabled device, you cannot use the unit wirelessly with those machines. Instead, you have to connect the TAE Core via USB. In a perfectly ordered world, that’s not a big problem. But if you use the TAE Core in a small studio—where one less cable is one less headache—or you prefer to interface with the TAE Core app on a desktop where you can toggle fast and easily between large, multi-track sessions and the app, the inability to work wirelessly on a desktop can be a distraction. The upside is that the TAE Core app itself is, functionally and visually, almost identical in mobile and desktop versions, enabling you to select and drag and drop virtual microphones into position, add delay, reverb, compression, and EQ effects, choose various cabinets with different speaker configurations and sizes, and introduce new rigs and impulse responses to a tone recipe in a flash. And though the TAE Core app lacks some of the photorealistic panache and configuration options in the OX app, the TAE Core’s app is just as intuitive.Less Is More
One nice thing about the TAE Core’s more approachable $699 price is that you don’t have to feel too bad on nights that you “underutilize” the unit and employ it as an attenuator alone. In this role, the TAE Core excels. Even significantly attenuated sounds retain the color and essence of the source tone. Like any attenuator-type device, you will sacrifice touch sensitivity and dynamics at a certain volume level, yielding a sense of disconnection between fingers, gut, guitar, and amp. But if you’re tracking “big” sounds in a small space, you can generate massive-sounding ones without interfacing with an amp modeler and flat-response monitors, which is a joy in my book. And again, there’s the TAE Core’s ability to “expand” as well as attenuate, which means you can use the TAE Core’s 30-watt onboard power amp to amplify the signal from, say, a 5-watt Fender Champion 600 with a 6" speaker, route it to a 2x12, 4x12, or virtual equivalent in the app, and leave your bandmate with the Twin Reverb and bad attitude utterly perplexed.
The Verdict
Opting for the simpler, thriftier TAE Core requires a few sacrifices. Power users that grew accustomed to the original TAE’s super-tunable “resonance-Z” and “presence-Z” controls, which aped signal-chain impedance relationships with sharp precision, will have to make do with the simpler but still very effective stack and combo options and the “air feel level” spatial ambience control.The DC power jack is less robust. It features only MIDI-in rather than MIDI-in/-through/-out jacks, and, significantly, 70 watts less power in the onboard power amp. But from my perspective, the Core is no less “professional” in terms of what it can achieve on a stage or in a studio of any size. Its more modest feature set and dimensions are, in my estimation, utility enhancements as much as limitations. If greater power and MIDI connectivity are essentials, then the extra 600 bones for the original TAE will be worth the price. For many of us, though, the mix of value, operational efficiencies, and the less-encumbered path to sound creation built into the TAE Core will represent a welcome sweet spot that makes dabbling in this very useful technology an appealing, practical proposition.
