Updated: October 7, 2020 by Richard Cole
Amp attenuators are devices that solve a very old problem that is specific to tube amps. If you want good distortion, you have to crank the volume to the max. This has to do with the fact that power tubes provide the best sound once they are under maximum load.
So in general, the rule of thumb is that the quality of sound increases with the volume. However, it’s impossible to play on max volume all the time, especially with large tube amp stacks. You just overpower everything and your amp gets too loud.
This is where power attenuators step in. These devices are placed between the amp and the speakers in the signal chain, and they convert some of the amp output into heat. By doing so, they allow you to experience the sound of fully loaded tubes at low volumes.
In other words, if you have a tube amp, you definitely want to have an attenuator at hand. We’ve selected three best guitar amp attenuators.
Let’s see what each one offers:
RockCrusher is a very rugged and versatile piece of equipment which is the attenuator of choice for many professionals. Thanks to its variable impedance, Rivera RockCrusher can be used on most vintage tube amps which lack the master volume.
Aside from showing you what your amp can really do without bursting your eardrums, RockCrusher has other features that make it an interesting platform.
One of the best attributes of Rivera RockCrusher is its ability to accomodate both 8-ohm and 16-ohm amps. You can select the impedance by simply flipping a switch.
There’s a balanced XLR line, and an unbalanced 1/4-inch line out which you can use to send the signal straight to a mixer for recording, or pair it with another amp if that’s what you want to do.
There’s a complete bypass button on the front panel which allows you to quickly access your amp in its unaltered state. Next to it, you have two EQ options – Edge and Warm, which increase the quality of highs and lows.
The case itself is pretty well made, and can take a lot of abuse before it gives. Overall the Rivera RockCrusher is a quality product, both inside and out, with reliable and durable components all around.
Rivera RockCrusher efficiently reduces the volume of your amp without killing the tone or responsiveness of the original signal. It gives you the best your tubes can produce at variable volume.
For the price, it’s a far better option than to chop up your amp or buy another purpose specific amp. This way you can do everything with the tubes you have.
HP8 Hot Plate is definitely one of the most popular power attenuators on the market. It’s simple, effective, and comes with certain features that are unique to this brand and model.
Unlike the RockCrusher we mentioned before, HP8 Hot Plate is locked to one impedance setting. In this case it’s the 8-ohm version while there are 16-ohm variants along with more obscure 4 and 2.7-ohm models.
THD Electronics HP8 Hot Plate sports a very simple design. The case is made of quality thick steel which protects the innards of the device just fine. On the front panel you will find all of your controls.
From left to right, there’s the main attenuation knob with five positions, the maximum one being -16dBs. This knob also has a Load setting which allows you to use the line out from the attenuator itself instead of a speaker box.
Next come the Bright, Bulb on/off and Deep switches. Bright and Deep options compensate for the lack of treble and bass in your tone by acting like a mini EQ. The Bulb switch is actually a noise reduction feature.
Once you turn it on, the signal passes through the bulb which eats up a good chunk of noise, giving you a cleaner sound. So that bulb is not there for show, it’s a practical way to reduce noise. Lastly there’s another volume knob which allows you reduce the volume even more.
The quality of sound you get with this attenuator, especially when connected to an old Marshall or Vox amp, is impressive. Not only is the sound retained in its full quality, but the dynamics are there as well. This attenuator does a great job at providing you with the same response you would have if you just cranked the amp to the max.
Compared to the previous two attenuators we described, the KLD/PAN PB-1 is a simple alternative that offers good performance at fraction of the price.
You don’t get many features, but it attenuates the signal just fine, and is practical for stage use as well as home use.
The case is made of aluminum alloy which makes this unit light and helps it cool faster due to the heat-sync design. There are only two controls available on KLD/PAN PB-1, the Attenuation knob and Level knob.
The first one allows you to determine attenuation with five settings including the full bypass, while the Level knob enables you to choose the right volume for your room.
When it comes to impedance compatibility, KLD/PAN PB-1 can work with amps of any impedance as long as they don’t go over the 100 Watt power limit.
Sound coming from this attenuator is decent to say the least. The signal retains much of its original quality. There’s no highs and lows compensation, however at this price, KLD/PAN PB-1 offers more than you would expect. If you need a decent attenuator for a reasonable amount of money, this unit is a good choice.
Attenuators are a must have for anyone who wants to experience their tube amp’s fullest potential.
These three offer varying levels of features and flexibility, but all three deliver a great sound. These are definitely some of the best guitar amp attenuators on the market.