Rivera RockCrusher Power Attenuator

Hands-On Review: Rivera RockCrusher Power Attenuator

Posted on .

It's good to have control issues

By Jon Chappell
Senior Editor, Harmony Central

A rider in Deep Purple's contract dictates that you hire them "as known." As they have been in the Guinness Book of World Records as the loudest band on earth, if you ask them to turn down the volume you would be in breach of contract. Early in his career, Stevie Ray Vaughan was fired from countless clubs for refusing to lower his volume. The distinctive sound of these artists required pushing their amp's power tubes to the limit. For years many guitarists have dealt with this issue by facing the amp to the wall, removing a couple of tubes, or putting a Plexiglas screen in front of the speakers. Others use a power attenuator: a device like a big volume knob that you place between the amplifier and its speakers.

Rivera was one of the first companies to offer an attenuator—the 1979 Super Sink. Their RockCrusher attenuator is the product of years of experience in this field.

Hot stuff

When a device soaks up the full power of an amplifier in an effort to reduce its volume, a fair amount of heat is generated. The RockCrusher is fully ventilated to allow much of this heat to dissipate. In addition the unit is overbuilt so that the components can weather the remaining warmth for a long time.

The output selector switch sports huge silver-plated contacts guaranteed for years of abuse. Each position lowers your volume: -3dB, -8dB, -16dB, and -20dB, producing a satisfying "clunk" redolent of industrial machinery. The unit is rated to handle 120 watts, though it is built to stay cool with more—just give it plenty of breathing room on the top and bottom.

High tolerance = great tone

The component tolerances in the Rivera RockCrusher are extremely high; this means whether you select the 8-ohm or 16-ohm setting you get that impedance—no matter which volume attenuation you choose. This is an important factor in maintaining tone.

Another tone-enhancing factor is that unlike some other power attenuators that offer a purely resistive load, the RockCrusher ensures that the amplifier and speaker see each other in a proper relationship of impedance and inductive/capacitive reactance.

I ran the Rivera RockCrusher between either an Egnater Rebel 30 or an Orange Tiny Terror and a 1x12" bottom sporting an Eminence Texas Heat speaker. The Egnater has a great-sounding clean channel that, sadly for my neighbors, comes up to near full volume almost immediately. Plugging into the Rivera unit allowed me to enjoy its rich sparkle at levels that wouldn't get me evicted. The lead channel of the Egnater, and the Orange with the gain cranked, retained their essential character at all output levels. Once I got below -16dB I found that engaging the Edge and Warm buttons acted like the loudness button on a stereo system, replacing the top and bottom frequencies lost when reducing volume.

The last click of the attenuation knob sent me into Studio mode. This further reduced the volume to levels that wouldn't wake my wife at night. It adjusts from quiet to off. Even at these minimal levels the sound remained musical without a trace of fizz.

Rivera RockCrusher Rear Inputs & Outputs

Get a load of this

Yes, I said you could turn the volume off. As a matter of fact you can unplug the speaker entirely as the RockCrusher operates as a load box as well as an attenuator. It offers 1/4" unbalanced and XLR outputs in the back to plug directly into a mixing board. A Line level knob adjusts the output.

I used the XLR out to run the signal into an M-Audio Firewire 1814 interface and record into Ableton Live. Once you remove the speaker from the equation entirely, a certain amount of fizz seeps in regardless of volume level. I was able to get rid of it with EQ but it wasn't quite a natural sound. Much better was running it through a cabinet emulation plug-in. Live's Cabinet plug-in did the job, but IK Multimedia's AmpliTube cabinet and mic sims made the sound full and natural. Thanks to the RockCrusher and AmpliTube's plethora of modeling options, I was able to get all the great tones produced by my two amp heads through many more cabinets than I own. Also, the amplifiers respond to pedals in a way that audio interfaces and software haven't yet mastered.


Unless you have the clout of Deep Purple or a secluded, soundproofed studio, playing through your amps at full volume is rarely an option. Master volumes can sound good but are no substitute for pushing the power tubes. Whether your amp runs at 8 or 16 ohms, the Rivera RockCrusher will let you drive it as hard as you like while monitoring at any volume you choose, and—most important—will preserve your tone in the process.

Features & Specs

  • Superior natural tone balance at any level
  • Selectable 8- and 16-ohm capability
  • Reactive internal network for true amplifier/load interaction
  • Immense thermal capacity ensures cool running and long life
  • Tight impedance tolerances
  • XLR and unbalanced line outputs with level control
  • Low- and high-frequency equalization selection
  • Load box and attenuator function up to 120W RMS capacity
  • Enormous and robust internal components
  • Full bypass capability with no insertion loss

Tags: Amplifiers Harmony Central

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