Rivera RockCrusher Attenuator Review
June 7, 2011
|Download Example 1
Amp volume (non-master) set at 7. Clip takes amp from no attenuation through each step of RockCrusher from Bypass to –3, -8, -12, -16, -20, Studio from max to min.
|Download Example 2
Same clip with volume adjustments in Pro Tools to compensate for DB loss up to –12 (maximum gain allowed on fader).
|Download Example 3
Attenuation at –3DB with no EQ switches, then engaging EDGE, then engaging WARM with same riff.
|Clips recorded with a 1970 Marshall Superbass through '68 Basketweave 4x12. Speakers are two G12H-30s and two Vintage 30s. Mic'd with Shure SM57 off axis through Chandler LTD-1 mic pre into Pro Tools.|
Many vintage amp enthusiasts would never dream of cutting into an amp or changing the circuit to accommodate a master volume, and that’s why the amp world is full of attenuators. And in the form of the RockCrusher, Rivera has built an attenuator that works with the most powerful amps while preserving that tone that led you to you most beloved amp in the first place.
Cut it Out!
Many attenuators go the route of a purely resistive load in an attenuator design, which can contribute to tone loss and performance issues. By using a reactive load network, the RockCrusher achieves a more balanced relationship between impedance and capacitance reactance. The intended result is better tone and feel and more equalization range when attenuation removes elements of speaker dynamics.
Built of 16-gauge welded steel in purple and black, the RockCrusher commands attention. It looks tough and retro all at once with giant knobs and switches that makes the ‘Crusher easy to work with and settings easy to remember. Like all things Rivera, this was clearly built with the highest-grade components and made to last a lifetime. Optional removable rack ears are available for road case installation, but if you prefer table- or amp-top use, the provided set of super heavy-duty rubber feet will hold it in place.
The front panel features an Attenuate/Bypass switch, Input Z (16/8-ohm) switch and two EQ switches (Edge and Warm). All switches are black, solid 2-way plastic rocker switches that engage with a satisfying click. A massive Attenuation switch has six settings in 4 dB increments from -3 dB down to Studio. When in Studio mode a second Level knob controls from Max to Min volume to take the level down to near zero. A Line Out that can be utilized for a slave out or to an outboard mixer.
On the back there is a balanced line output (XLR) followed by an unbalanced 1/4" line out, two speaker output jacks, and a single Z Input (8 or 16 ohms) that takes the output of the amp being utilized. Connection is as simple as taking the output from the head into the input, then connecting one or more of the outputs to the speaker cab of choice.
After working out of a local studio with a great live room for the past four years, I was spoiled being able to sit in the control room with a 100-watt Marshall and a cranked cab mic’d in the live room. But these days I spend most of my time in my home studio. The only problem is I still have all the non-master volume amps and the cabs but it’s a single room and even 20 watts can blow the windows out. So to test out the RockCrusher I lined up a bevy of vintage Marshalls, a ’64 Vox AC30, and various other amps that were around during review time to see how it held up on the whole lot. My test cabs included a 1968 Marshall Basketweave with two Celestion V30s and two original G12H-30s, a Mojave 2x12 with Greenbacks, and a Krank 1x12 cab with an Eminence Governor.
First amp up was a ’68 Marshall Plexi PA head that was voiced as a Superbass—probably the loudest and richest sounding of the amps in my collection. Selecting 16-ohm operation and bypassing the Rock Crusher I pushed the PA up to about 7 on the volume and let it rip. By the time I was picking up some of the art that had fallen off the walls, I had dialed in a tone I liked and switched on the RockCrusher in the -3db mode.
With the RockCrusher on, the tone was definitely darker than in its un-attenuated state. But a quick flip of the Edge switch reinvigorated and filled things out. Moving through the attenuation settings the signal it became quieter and quieter but the tone stayed very consistent. Amp settings didn’t need to be changed to retain the classic Marshall sound as it dropped in volume.
Sensitivity to pick attack changed and became a little less clear as the extreme settings came into effect. And I found that once past -12db the feel of the amp became more compressed and less affected by digging in or pulling back on the attack of the instrument. This is to be expected, and I’ve yet to use any attenuator that really can retain the dynamic touch of a big amp up at full volume. There are simply too many other factors to expect that a 1-watt tone will feel the same. That said, it surprised me in recording how similar the tones alone remained.
Moving onto another powerful amp, I plugged in the AC30 in and used the original speakers from the combo (original Blues from ’64). Since the AC30 is an 8-ohm amp I made the switch on the front panel to accommodate the impedance change. The AC30 worked extremely well with the RockCrusher—even more so than the Marshall. Tone stayed intact and sounded beautiful and shimmering, just like the amp always did but without the unbelievable volume. Just shaving off 8 dB put it in the perfect spot to record without the unnecessary noise, and I engaged the Warm switch to add a little bottom end.
With a Blackheart Little Giant and Krank 1x12 cab I set up the RockCrusher to see what it would do to a little amp. I quickly found that -3db was really all that was necessary to tame the five-watt amp, though it did subtract some of the Blackheart’s richness. Engaging the Edge switch was necessary to gain back the brightness that was lost in attenuation but the Warm switch made the bass a bit tubby. In recording mode I was able to bring the amp down to a near whisper and still got great results that didn’t sound very far off of the full volume version of the head. Not many people are going to attenuate a five-watt amp these days but it’s nice to know in a pinch that this is a possibility.
The balanced line output is a great way to get the direct signal of the amp into Pro Tools. Since I sometimes run speaker emulation software for tones this ended up being a great way to get live, cranked amp tones simply by applying speaker emulation to the DI tone of the amp. You get all of the amp sound on the output without the speaker tone. This is definitely something to consider if you’re setting the RockCrusher at ultra low volumes and still want to have options later.
Attenuation is tough business. The single largest factor outside of tone, is retaining the feel, touch, and response we love at higher volumes. Rivera has done a commendable job in helping to retain that with the reactive load. It’s built to last, looks great and saves amps from being chopped with unnecessary modifications. It is also safe in handling 100-watt tube amps with headroom to spare. At about 500 bucks it isn’t dirt-cheap. But it’s way less than buying an amp for every occasion and enables you to work with the amp you know in any situation.
you have high-powered vintage or modern amps that need taming without sacrificing too much tone or feel.
you run lowered powered master-volume amps or regularly play Cobo Hall with six stacks.
Street $499 - Rivera Amplification - rivera.com