Review: Peavey ReValver 4 Guitar Amp Simulator

Rockin' Amp Sim Adds Awesome Guitar Modeling and More

ReValver's GUI has been rebuilt from the ground up. The Peavey ReValver guitar-amp simulator has won adoring praise for its tube-like tone and deep editing capabilities: Even the modules’ tiniest virtual electronic components—tubes, transistors, capacitors, and the like—are subject to your hot-rodding whims.

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ReValver 4 ups the ante, big-time. The new release adds guitar modeling that alters the tone of your axe to match another’s, placing the sound of numerous virtual acoustic and electric guitars at your fingertips. The new RIR 2 cabinet modeler attains a higher level of realism than the legacy RIR module by emulating the impedance interaction between the selected cab and amp (see Figure 1). But we’re really talking a complete makeover here, as ReValver’s audio engine and GUI have been rebuilt from the ground up, adding real-time 64-bit operation to its legacy real-time 32-bit and offline 64-bit modes. The cross-platform amp simulator comes in both lite and full-featured versions, the former offered as a free download.

Both a standalone application and plug-in (in VST, AU, and AAX formats) are included. I reviewed the AU plug-in in MOTU Digital Performer 8.06 (DP), using an 8-core Mac Pro running Mac OS X 10.9.5. My sonic assessments were made playing a ’62 Fender Stratocaster routed in series through a Millennia TD-1 recording channel (set to contribute the least amount of coloration: DI input/FET gain/ transformerless output), to an Apogee Rosetta 24/96 A/D converter, and into the digital input of a MOTU 2408mk3.

Fig. 1. ReValver’s Amps & Cabs view. In the RIR 2 module (at the bottom of the GUI), note the disclosure arrows for the separate pop-up menus for cabs and mics. Clicking on any of the dots on the RIR 2 speaker icon moves the virtual mic to the corresponding position. Clicking on the shopping basket (top right of GUI) takes you to the online Amp Store.Fig. 2. The ACT preset menu, showing stock content and additional Amp Store instrument models. ACTING UP

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ReValver 4’s outstanding new guitar modeling (dubbed Audio Cloning Technology, or ACT) analyzes the tone of your strummed guitar at the amp sim’s input to create a sonic profile of your instrument (see Figure 2). Then, using presets stored in a pop-up menu, it changes your guitar’s tone to that of a different acoustic or electric guitar. You can click a preset’s audition button to hear a short recording of the actual guitar that was modeled. ACT also lets you shape the tone of your complete rig—or two rigs set up in parallel signal paths—at ReValver’s output. ReValver 4 also includes a new normalization function that sets the optimal input level for the guitar you’re using.

The new RIR 2 Cabinet Simulation Module is far more versatile and user-friendly than the original RIR, parsing the cab and mic selections into separate pop-up menus (instead of an integrated impulse response) and allowing you to graphically edit the mic’s placement on the speaker cone (angled on- or off-axis) and add room ambience. You can still use the original RIR interface, which is especially useful for loading third-party impulse responses.

The standalone version of ReValver 4 offers Gig Mode for live use. Using MIDI Program Changes 1 through 8 in turn, Gig Mode switches seamlessly among eight presets you’ve previously loaded into slots at the top of the GUI. Three filters let you tweak the tone of the eight presets as a whole, optimizing their sound for a particular P.A. system, hardware-based guitar rig, or venue. The whole enchilada can be saved as a bank and different banks recalled for, say, different sets you plan to play live.


The free version of ReValver 4 includes two amp modules, a lite version of the aforementioned RIR 2 Cabinet Modeling module (featuring three cabs and three mics with multiple mic positions), two stomp boxes, one effects module, a signal splitter (for playing through two rigs in parallel), several ACT input (acoustic- and electric-guitar models) and output (global tone) presets, and access to Peavey’s online Amp Store. (Enter your account there by clicking on an icon in the GUI.) At the Amp Store, you can purchase more than 100 additional amps, cabs, stomp boxes, effects, and ACT bundles à la carte using PayPal; prices range from $1.99 for a RIR 2 cabinet to $7 for an amp module.

To get all the features for ReValver 4 described in this review—plus dozens more cabs, mics, stomps, and effects and ACT Strat and Les Paul preset bundles—you’ll need to buy the ReValver 4 Producer Pack or upgrade to it from ReValver MK III.V. Besides a much greater selection of mics and RIR 2 cabs, the Producer Pack includes re-modeled versions of most of the amp and effect modules that came with MK III.V. The Amp Store offers a boatload of additional content. Because ReValver 4’s models and code are all new, MK III.V presets are not forward-compatible with it.


Peavey asserts that ReValver 4’s ACT modeling involves more than just EQ matching, and my listening tests confirmed this: I could clearly hear saturation changes for different electric guitar models, and dual-pickup selections produced euphonious phase changes. While there are many terrific-sounding electric-guitar models offered, I wasn’t impressed with the acoustic-guitar presets (at least not with electric guitar input); they tended to sound glassy and brittle. A blend control let me adjust the balance between the sound of my Strat and the selected model, creating a hybrid instrument. Cool!

At the time of this writing, ReValver 4 loses your ACT guitar profile when you switch global presets, making you prompt ReValver 4’s analysis of your instrument again. Peavey promises an update that will allow you to store your guitar’s profile within a preset. One application this will allow (using the standalone application’s Gig mode) is instantaneously switching virtual guitars playing through different amps and cabs, all with one simple MIDI Program Change command.

The new RIR 2 cabs and World Wide Verb effects module (combined reverb and delays, with filters) sounded excellent. I also really liked the Again Stereo Delay module (which has a tap function) when set to produce discrete echoes; with its chorus and ambience effects defeated, it sounded wonderfully warm and lush. I wished the new Käften Noise Gate module offered an adjustable range control; it didn’t always eliminate enough noise when using high-gain setups. The new Square-Phase stomp and Digital Flanger sounded a little thin to my ears.

ReValver 4, like earlier releases, can’t sync parameter values for time-based effects (delay, chorus, flange, and reverb) to the host’s tempo, but Peavey promises to implement this soon. There are still no undo and redo functions, making edits a unidirectional process.

But Peavey got the most important stuff right: excellent and wide-ranging electric-guitar tones, deep editing capabilities, and an extremely intuitive and well-organized user interface. The inexpensive price makes the ReValver Producer Pack a compelling choice for new buyers, and the ACT instrument modeling alone makes an upgrade from MK III.V an absolute must. ReValver 4 is a winner!

STRENGTHS Sounds terrific overall. Versatile. Easy-touse. Deep editing. Expandable through the Amp Store. Gig Mode for live use. Inexpensive.

LIMITATIONS ACT (guitar input) profile is volatile. Timebased effects do not sync to host’s tempo. Acoustic guitar models and some effects fall short. Not compatible with MK III.V presets.

Peavey ReValver 4: Basic: Free; Producer Pack: $99.99; upgrade from MK III.V: $49.99


To help ReValver record an accurate sonic profile of your guitar, first select an instrument preset (a modeled guitar) in the ACT input module. Click on the preset’s record button and strum bar chords—alternating up and down strokes—up and down your guitar’s neck until the profiling process completes in about ten seconds.

Michael Cooper is a recording, mix, mastering, and post-production engineer and the owner of Michael Cooper Recording in Sisters, Ore.