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Peavey ReValver Mk III ($250)

Amp Modeling Software in Plug-in and Standalone Versions

By Jon Chappell



With the release of ReValver, Peavey stepped into the land of software-based guitar-processors already staked out by several established players with evolved product lines. But Peavey knows a thing or two about guitar sounds and high-tech audio, so combining their strengths in ReValver was a natural move, even if they were a little late to the party. Having had the benefit of waiting, Peavey came up with a novel slant that focuses more on tweakability than graphic niceties, and throws in a unique, unprecedented game-changing feature its own. In other words, Peavey has made all the right moves with ReValver Mk III, their latest incarnation. It’s powerful, deep, treats you like an adult, and sounds great. ReValver gets my unqualified recommendation based just on its sound quality and ease of use. And as a bonus, if you’re a gearhead who likes to micro-edit your sound down to the bias voltage on your preamp tubes and the flux leakage on your output transformer, boy, are you in for a treat!


ReValver Mk III runs as either a standalone application or as a plug-in within a host DAW or audio recorder/editor. Peavey recently added RTAS (Pro Tools’ plug-in protocol) to its existing versions of VST and AU, so ReValver will now run on virtually any major Mac or Windows audio application. To get the specs, system requirements, and latest updates, visit We’ll skip all the stuff about installation routines and such (no problems there) and get right to the program as it’s up and running and facing you on your computer monitor.



ReValver’s interface is quite straightforward, employing the metaphor of a rack and modules. Simply click on an open rack space to add a module from any category (stompbox, preamp, poweramp, effects, speakers, etc.), all of which are uniform in width (though varying in height), based on the proportions of real-world 19" rack-mounted gear. This consistent treatment makes ReValver’s operation virtually self-explanatory. Just keep adding modules of any type until you have all the elements you need.


Once the modules are loaded into the rack, you can drag and drop to rearrange them or use Delete, Replace, and Insert Here commands, giving you two ways to quickly arrange the modules in any desired order. Aesthetically, the rack approach is quite readable and satisfying. And one nice touch: at the top of the window is an unobtrusive, always-on CPU meter—handy when using a laptop or other computer where CPU resources need monitoring.


Once you click a rack space and select a category, a page pops up that shows the name, picture, and detailed text description of each module. The photos allow for a quick visual ID of the effect, and the descriptions are well-written and helpful (see Figure 1). What leaves this approach wanting is that it requires you to scroll down the page to see everything. There’s no at-a-glance assessment of, say, all 19 stompbox choices. Only the first six show up upon invoking the category page, and the smallish window is not resizable. Also, my mouse’s scroll wheel, which works on all of my other applications, both music- and non-music-related, wouldn’t scroll these windows (nor are my arrow or page-up and page-down keys operational). So until you really get to know all the available modules in ReValver, you’ll have to manually scroll down the page to see all options.



Fig. 1: ReValver uses a rack metaphor into which you plug in modules of seven types: Stompboxes, Amps, Preamps, Poweramps, Speakers, Effects, and Tools. Once you click on a category, a page of helpful information pops up to help you choose.


Though the graphic renderings of the modules are quite attractive, in working with ReValver, I found some aspects of the interface to be a little primitive (there are typos in some of the text boxes and labeling is inconsistent). But from an operation and sound-quality perspective (which is what I deal with in the rest of the review), ReValver is all top-flight stuff.


Front Panel Editing

Once you have a signal chain going—either from your own creation or pulled from the provided bank/program presets—you can tweak the front-panel controls to fine-tune the sound. All the knobs and switches work well producing desired results, and are easy to adjust.


In addition to these grabbable controls, ReValver offers additional editing levels. In the Speaker Construction Set from the Speakers module, for example, clicking on the front panel icons yields further menu choices, whereby you can adjust the width, height, and depth of the cabinet, select the type of speaker (Celestion, Jensen, etc.), choose your microphone, set the distance of the mic from the speaker and cone, and angle two mics in relation to each other if you’re in a stereo configuration. Talk about fine-tuning! And it really gets intense once you go to Tweak mode, but that’s ReValver on a whole other level, so before we get to that, let’s check out the sounds.


Guitar Tone

To test ReValver Mk III for this review, I broke out my two test mules for amp sim. work—a Carvin Strat with Seymour Duncan Alnico II Pro pickups and an early-’80s Les Paul Standard with Burstbucker Pros. I ran the guitars through an M-Audio Fast Track Ultra interface using ReValver in both standalone mode and as an RTAS plug-in in Pro Tools 8. As mentioned, ReValver provides some well-crafted presets, and I found these to be great templates for auditioning classic and modern setups. I was pleased to see that when selecting modules in the “amp” category, ReValver loads two modules for you: the amp head module and a speaker module. You can selectively delete either, but having this two-for-one load-up is a real time saver. If you prefer to build your signal chain à la carte, you can load up preamp, poweramp, and speaker modules individually. Selections in the amp category not only give you a package deal, but the controls are pre set to useful sounds, as opposed to an all-12:00 default. For example, the JSX amp setup sounds just like Joe Satriani’s tone on “Satch Boogie.” Thoughtful stuff here.


Continuing on my tour of the modules, I loaded stompboxes, preamp, poweramp, and speaker configurations with abandon, yielding sounds from sparkly clean Fenders to bright-and-brassy Voxes to scathing metal Marshalls—rendered quickly and on-the-fly. The quality was stunning for its own sake, and in the way the effects names matched their expected sound (e.g., “Greener” for a Tube Screamer-type effect, “Sheriff” for a raspy Texas twang, etc.). All sounds derived from the amps were dead-nuts on for providing emulations of classic rigs, Peavey-made (JSX, Classic 30, 6505, ValveKing, Triple XXX) and otherwise. The tone, response, and “feel” of the sounds are uniformly excellent—guitar-authentic, musically versatile, and latency-free. To round out your signal chain in the virtual domain, ReValver offers a complete menu of EQ, time-based, and modulation effects as well (see Figure 2). To ensure the best fidelity possible, ReValver offers a 64-bit mix down mode. You don’t need it to create sounds, and it requires more CPU power, but invoking it before you render or mix your music to disc ensures the smoothest sound possible.



Fig. 2. A rack full of modules—stompboxes, preamps, amps, speakers, effects, etc.—ReValver-style.


In addition to the full complement of tone-shaping components, ReValver also throws in several utility modules under the Tools category, including a tuner, signal leveler, and frequency analyzer. A very powerful tool here is the signal splitter, which divides the signal into two chains. Each runs in parallel using its own set of modules; when summed at the “signal merge” module, the two chains become one signal again, but with control over the pan and blend of each chain and the ability to phase-invert one of them. Also handy is a VST host module (it’s actually listed in the Effects category), which allows you insert any VST plug-in resident on your hard disk right in the rack, as if it were another ReValver module! Some of these tools are reminiscent of analysis features found in advanced waveform editors, like WaveLab, Peak, and Sound Forge. If you’re dealing with a complex mix and you want to be sure your guitar sound will play well with others, consulting these tools will help you in placing your sound in the mix. But we find even deeper stuff if we care to really roll up our sleeves.



The Tools menu provides just a glimpse into an altogether different dimension of ReValver, and its secret weapon: Tweak mode. Like a special key into the software itself, Tweak mode allows you to go under the hood and venture far beyond what the front panel offers to a level of control that is unprecedented in other amp modeling programs.


The manual states that Tweak mode “was written on an engineering level using real schematics by a real tube amplifier company,” and of course this is true: Peavey makes real tube amps, and the objects within this interface are derived from the actual schematics of those amps, and allow you to not only swap out 6L6 tubes for EL34’s (something that’s impossible on a real amp without physical modification of the circuitry and chassis), but alter the internal electrical properties of the tube itself—and then hear the results of your efforts. Tweak mode is what all the buzz is about regarding ReValver.


You can invoke Tweak mode from any module. Five analysis tools appear—Frequency Analyisis, Harmonic Distortion Analysis, Oscilloscope Analysis, Transient Analysis, and Save as Impulse Response—and are common to all modules in Tweak mode. The Impulse Response tool is a neat feature: it allows you to save or load impulse responses of things like cabinets and reverbs created in other programs. Additional objects called Power Supply, Output Transformer, Negative Feedback Loop, and Signal Input/Output Shaping appear where appropriate (in amp, preamp, and poweramp modules). Below this row of tools is shown the amp’s topology, including tone stacks, tubes (preamp and poweramp), and gain controls—all editable (see Figure 3).



Fig. 3. Tweak mode for an amp module, showing seven tools across the top (left to right) Frequency Analysis, Harmonic Distortion Analysis, Oscilloscope Analysis, Transient Analysis, Save as Impulse Response, Power Supply, Output Transformer, Negative Feedback, Loop, and Signal Input/Output Shaper. Below the top row are icons (tube and gain knobs) showing a given module’s topology. Clicking on any icon brings up a window with editable parameters.


Let it be said that Tweak mode is no gimmick. Its comprehensiveness is unparalleled in any other tone-modeling application I’ve seen—and daunting to anyone without extensive experience or formal training in electronics and amplifier design. There are scores of editable parameters contained here, with highly technical functions and corresponding terminology. To take just one example, the Power Supply module has variable parameters called Diode sagging, Drain/Time Constant, Charge Speed/Time Constant, Filter Tap/Capacitor Size, and Influence/Amount. The Audio Transformer features Primary and Secondary High and Low Pass controls, Direct Magnetic Flux, and Flux Leakage (see Figure 4).



Fig. 4. The editing windows for the Power Supply and Output Transformer (also called Audio Transformer here) in Tweak mode.


In the section showing the amp’s topology, components include preamp and poweramp tubes, which you can swap out at will. But you not only have the ability to swap a tube with any of 16 other choices, you can drill down and edit a tube’s electrical characteristics, too. Clicking on any tube icon opens the window appearing in Figure 5, enabling you to change any aspect of the tube—even to the point of dialing in values that are contradictory or physically impossible in the real world of glass and metal. In this window, you can change anything from the transformer impedance to the cathode resistor value to the bias voltage, and more. You can opt to include a cathode capacitor (for better high-end response) and if so, give it a value from 0.0010 microfarads to 50 microfarads—a range of almost 500,000 microfarads!



Fig. 5. Clicking on any tube in Tweak mode opens this window, allowing you to choose among 17 different tube types, and to adjust the electrical properties of the tube itself.


For those who are unfamiliar with the concepts here, helpful mouse-over text bubbles tell you roughly what each parameter’s effect has on the circuitry or sound. Changing any of these parameters influences everything else in the circuit. But because it’s all in the virtual domain, you can’t short anything out, melt components, start a fire, or otherwise do any damage. Casual tinkerers can experiment with impunity, and are encouraged to do so. One of the first things I did was to take a basic Marshall sound that uses an EL34 and swap it out with a more Fender-like 6L6.


Even if you don’t engage in micro-editing on the circuit level, Tweak mode has other benefits. Ignoring the tools in the top row, you can view just the amp’s topology to quickly reverse-engineer its elements. It’s much easier to compare the gain stage structures of two amps using Tweak mode than by eyeballing the graphically varied front-panel designs. For example, if you’re not sure from the front panel whether an amp is a true discrete, two-channel design or just a single channel with an additional boost circuit, Tweak mode will reveal this instantly (see Figure 6).



Fig. 6. Viewing an amp’s topology (the icons of tubes and knobs arranged left to right) is a way to compare the front-panel structures of different amps quickly, easily, and in a consistent way. In this example, the Peavey ValveKing, the channel is set to the clean stage, so the front-panel’s volume control is grayed out because it’s unavailable (as shown as the top level in the topology).


Tweak mode is not only instructive (even if your circuit-altering efforts are mostly trial and error), fun and addicting, it opens up an entirely new channel for sculpting your sound down to the most elemental level.



Anything I found wanting in ReValver was based on little interface infelicities. The module-selection window should be sizeable and scrollable, and optimized for more efficient use of space (with fixes to typos and inconsistent labeling). As far as operation as a guitar-sound simulator, ReValver does a fantastic job of creating complete signal chains of any complexity quickly and easily. I put it up against three other well-known software-based guitar processors, and ReValver at the very least held its own with its peers as far as configurability, and in some cases, surpassed them (64-bit mix down option, the Signal Splitter, and Impulse Responses tool being standouts). You can virtually sail through the editing process here, saving your work, loading banks and programs, and making adjustment both radical and subtle.


But in two areas, ReValver just shines: Tweak mode and sound quality. ReValver’s Tweak mode has no peer in other guitar amp sims. You may not ever have occasion to adjust the bias in your 12AX7, but the option is there if you ever have the urge, and you can then invoke the analysis tools to reveal the effect your tweaks have on the rest of the circuitry and the sound. In my tests, the additional tweakability of some parameters (especially in the power supply, output transformer, and selection of output tubes) were just three common go-to adjustments I often made that gave ReValver an edge in flexibility over other programs. And it changed the tone and feel in subtle yet perceptible ways.


The sound that ReValver produces is just fantastic—uncanny in its emulation (especially in stompbox and amp modes), realistic for guitar sounds in its own right, and expressive and musically useful through all ranges of the editable parameters. I never found a single amp, preamp, stompbox, or effect that didn’t significantly contribute some vital sonic component to my signal chain. ReValver was clearly designed by musicians who have ears along with programming chops.

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