Amp Attenuators: What You Need to Know
Electric guitars are meant to be played loud... at least that’s what the tone heads will tell you. And this mantra comes with some real-world proof to back it up. Ever tried playing on a cranked tube amp for a while? Well if you have you’ll know that once you turn it down it just doesn’t sound the same. Not only is there a thrill to playing this instrument at louder volumes, the tone can literally increase as the volume knob is turned higher. Furthermore, with more and more players dealing with neighbors and decibel policed venues, that cranked tone is becoming harder to achieve practically. Because of this, many guitarists are turning to other solutions to get all that loud amp sound into a lower volume setup. At the forefront of these solutions exists what is known as attenuators. But is that the solution for your situation? And how does attenuation work anyways? These are just a couple of the questions I hope to clear up for you. So, let’s begin.
The Master Volume Knob
Many amps since the 1970s up through today have included the feature known as a master volume control. The master volume knob is what many of us use to control the overall volume of our amps. And while some early master volume controls sat a little earlier (Pre-Phase Inverter), they now really do control more of the total amp volume and not much gain at all.
How they work is quite simple in terms of amp design and electronics. Basically, the knob works just like any other potentiometer and is placed later in the circuit than the initial volume control. The initial control I am referring to is what many people will know as the gain or drive knob. This knob has to do with how hard you are hitting the preamp/front of the amplifier circuit while the master volume is later on. In amps without a master volume control, the single volume knob is working as a gain knob would on master volume amps.
The idea of a separate master volume and gain control makes it sounds like it should be all that you could need. But unfortunately, this design is not a perfect one by far. Many players find this out the first time they crank the gain and roll down most of the master volume to compensate. Often this method for volume control will result in a rather weak and tin-like timbre. This is due to the fact that no master volume knob is controlling what is directly happening with the output tubes. They only have a real impact on what is happening in the circuit up to that point. Thus, we are left with master volume knobs that take away some “tube tone” when setting at a too low of a level.
What is an Attenuator Doing?
In essence, an attenuator is simply soaking up some of the output volume without affecting anything else. So, the idea here is, that you are able to maintain all of your lovely output tube saturation while still being able to lower the volume. How is this accomplished? First understand that when you add an attenuator to your rig, you are connecting it so that it sits after your amp and before your speaker(s). From an electrical standpoint, attenuators are actually pretty simple devices, described as reverse amplifiers. Now, if you’re like me, you may be wondering why these are not placed in every amp instead of master volume controls. There are a few reasons, but the main being that there are still a lot more components and heat to deal with than that of a simple potentiometer. However, on occasion you will see amps that have built-in attenuators, just look at many of the Tone King models.
In case you were wondering what, the difference is between an attenuator and a re-amp box, they are very similar. Both of these devices really have a similar end result, the difference is in the way they achieve that result.
Resistive vs Reactive Attenuators
While you won’t see nearly as many modern resistive attenuators, it is still important to recognize the difference. Initially, most attenuators were resistive, meaning that they have a fixed impedance. And while most people are not aware of this, the impedance of your single is actually fluid when going into a traditional amp to speaker setup. The potential effect of going through a resistive attenuator is that of feeling less responsive than just going into the speaker directly. This is why reactive attenuators were developed for guitar amps. This type of attenuation introduces a speaker motor to get back the dynamics lost by having a fixed impedance. As you could have guessed, this process makes your amp interact with the speaker the same way as if there were not an attenuator in the way.
Best Attenuators for Different Budgets
Not all attenuators are created equal. Sometimes if you get a poorly made unit it can actually hurt your tone to the point of being worse than just turning down the master volume on your amp. Additionally, there has recently been an increase in hybrid attenuators hitting the market. Units like this often get into things like impulse response and remove the need for a cabinet entirely. I have assembled a list of three different categories of attenuators that are all great units for what they do.
Affordable and Basic: these attenuators are not going to break the bank and are also easy to get up and running with.
Bugera PS1 – $116.00 :
- Works with 4, 8 and 16 ohms
- Can Take 100 Watts
- Gets the job done
- The price is right
- Audio quality is not as great it could be
- May not hold up over time if gigging
Two Notes Torpedo Captor – $269.99 :
- Has some great included software
- Takes up to 100 Watts
- Does speaker simulation
- Sounds super solid
- You have to buy a specific unit for 4, 8, or 16 ohms
Middle of the Road: if you want basic attenuation but with excellent audio quality and a little more versatility.
Tone King Ironman II Mini – $395.00 :
- The pedal format is useful
- Presence switch to add back in upper mids
- Sounds great at any level
- Very nice construction
- Only 8-ohm operation
- Only can take up to 30 Watts
Rivera RockCrusher – $549.00 :
- Handles 8 or 16 ohms
- Takes up to 120 Watts
- Rock-solid construction
- Great for the gigging guitarist
- Adds almost no coloration to your tone
Best of the Best and Most Feature Packed: for those who are looking to get into IR and cab replacement along with getting some of the best audio quality possible. These things are much more than simple attenuators.
Universal Audio OX – $1299.00 :
- Great as a DI
- Can remote control wirelessly via the app
- Simple for how much there is
- The UA presets/IRs are great
- High-quality effects
- Can’t load custom IRs
Boss WAZA Tube Amp Expander – $1299.99 :
- Fantastic attenuation control (reactiveness)
- A lot of control in the editing software
- Can load in custom IRs
- Internal effects can come out of the speaker out
- Might be a little overkill for some
That covers a lot of the basics for getting into attenuators. Obviously right at the end there I started to dip into IRs and cabs sims, that is another topic for another day. But as far as attenuation goes, you ought to have a pretty good idea of what it is and what it could mean for you and your situation. Many players and home recordists have already been taking advantage of great units like the ones listed above. It just might be time for you to do the same.