It’s no secret that tube amps just sound better when cranked. Finding the right balance of drive to the preamp and power sections results in an undisputedly heavenly tone. But many tube amps become unmanageably loud when played at the volumes needed to achieve this. This is where a guitar amp attenuator comes into play.
In short, they allow you to push the settings of the amp to really cook and get the tone you want at any output volume. They do this while absorbing some of the excess signal that is being sent to the speakers.
But nowadays attenuators can do much more than just that. In recent years new models have added some awesome additional features like cabinet, microphone, and room simulations, complex routing, and even on-board effects! In this guitar amp attenuator guide we’ll explore how they work, why they might be the perfect addition to your rig, and some of the best according to different categories.
What Does a Guitar Amp Attenuator Do?
Fundamentally, attenuators allow you to get the golden tone that high wattage tube amps produce when cranked – but at reasonable volume levels. Placed between the output of the amp and the speaker it diverts some of the excess power so you can hear the tonal characteristics at manageable volumes. Many of them use a coil that tames the wattage by converting it to heat, and whatever is left is sent on to the speaker.
Don’t Blow It!
There are certain criteria that must be met when working with an attenuator, and it’s critical to understand this. Items like your amp’s power rating and the impedance (some amps have selectable impedance) are vital to keep in mind to prevent damage. The importance of proper power handling cannot be stressed enough. If you have any questions or concerns, contact the manufacturer of the attenuator you’re interested in to make sure it will play well with your other gear.
Reactive vs. Non-reactive Loads
Again, it’s important to note that the impedance matching techniques that are necessary when connecting amps to speakers. This is because speakers operate the same way when using an attenuator or load box. So, if your amp has an output impedance of 16-ohm then it will need to see a 16-ohm load from the attenuator or speaker cabinet.
Power ratings are also vital as the attenuator must be able to handle the rating of the amp. The peak power of an amp often exceeds its stated power. A 100-watt tube amp can easily reach up to 150 when pushed that hard, so if you have a 100 watt amp, you’ll need an attenuator that can handle more than that. And always use designated speaker cables to connect amp -> attenuator -> speakers.
Creative Tone Choices
Have you ever wanted to run your Marshall head into a Vox cabinet, or maybe try matching a Fender with an Orange? Attenuators allow for all types of creative experimentation – providing the impedance and power settings are dialed in correctly. This can also come in handy when using house backline cabinets so you can keep your tone consistent.
Passive vs. Active Attenuators
There is some confusion around passive and active attenuators. The biggest difference between the two is that active designs are able to boost or cut the signal going to the speakers. This means they are just as good at taming powerful amps as they are at bringing up lower wattage amps.
Best Amp Attenuator: Universal Audio OX
The OX is truly a beast of burden and one of the most comprehensive options. This all analog piece provides reactive loading as well as impulse responses. Via Universal Audio’s Dynamic Speaker modeling technology, you also get access to world-class cabinet and mic simulations. It’s notorious for complementing tube amps but works just as well with solid-state. The reactive loading responds just like a real speaker would. Three different outputs let you connect in unique ways. Studio musicians love it because of the range of speaker sounds it provides, and gigging musicians love it for how well it maintains the amplifier’s signal purity.
Best Next-Gen Attenuator: BOSS Waza Tube Amp Expander
It doesn’t just attenuate, it evolves your amp’s capabilities. By way of powerful 24-bit/96kHz digital processing you get attenuation, cab simulation, effects loop, and reactive loading. You’re not stuck with the on-board sounds as you can fill the four impulse slots with your own impulses and cab sounds. It also comes with 10 BOSS effects. It can handle tube amps up to 150 watts.
Best Under $1000: Radial Engineering Headload
Used by some of the biggest artists this professional unit has two Dis (pre and post EQ) and a six-position voicing switch that selects between cabinet sounds. A two-band EQ gives you another level of adjustment. The proprietary Phazer section aligns the direct and microphone sounds so you can find the perfect blend. A sophisticated output section has balanced, unbalanced, and speaker load connections.
Best Under $500: Rivera Mini Rockcrusher
Rivera has been making attenuators for years and this is a great budget option. A rotary switch offers six different cabinet voicings, or you can bypass that altogether. It easily handles even the most powerful amps. The output can be split into EQ and non-EQ signals and all outputs can be run simultaneously.
Buy now ($399):
Best Budget Attenuator: Two Notes Engineering Torpedo Captor
This budget model definitely doesn’t skip on features or capability. It is a reactive load box, attenuator, speaker simulator, and DI all-in-one that works with amps up to 100 watts. It comes in 4,8, and 16ohm models with a number of output options. The speaker sims offer guitar and bass models.