weber attenuator
On the hunt for great tone at low volume? Join our columnist’s safari.
I’m on the hunt for an attenuator, so I’ve been prowling music shops and hunting online to find just the right one that will preserve my tone, but reduce it to a volume that will keep the neighbors from calling the cops—or keep a club’s soundman off my back.
“What’s an attenuator?” That’s a question we get a lot at PG, and the answer is: a device that allows you to drive your tube amp hard without the volume that comes with turning up. As we all know, pushing tubes really makes an amp sing, and getting that tone at a reduced volume can be a feel-good experience for everybody.
An attenuator is connected between an amp and a speaker using two regular speaker cables—one from the amp to the attenuator and one from the attenuator to the speaker. Then you dial in your tone and volume, and you’re set.
“Pushing tubes really makes an amp sing, and getting that tone at a reduced volume can be a feel-good experience for everybody.”
There are four types of attenuators: passive, active, resistive, and reactive. Passive attenuators rely on weakening the power of the signal and improving the impedance match between the guitar and the amp. They don’t require any sort of external power supply, and they used to have a reputation for frying tubes and overheating amps, but modern tech has reportedly cured those concerns. Active attenuators do require external power. This is because they are designed not only to attenuate a signal but also to boost it. So, essentially, an active amp attenuator takes a portion of the amp’s signal and reduces it or increases it to give it more drive.
The main difference between resistive and reactive load attenuators is that a reactive attenuator lowers the amp’s output while maintaining its impedance curve. This means that, regardless of the amount of attenuation, your tone will maintain as much transparency as possible. Resistive attenuators don’t maintain that impedance curve, and as attenuation increases, the color of your tone changes, becoming more compressed and darker.
Now, let’s take a look at some of the attenuators I investigated, in different price ranges.
JHS Little Black Amp Box
This is a passive attenuator, meant for use only through an effects loop. It does an effective job of attenuation, but it sounds thin compared to the active (and more costly) attenuators I listened to. It changes the tone more, too, but at a $65 street price it can easily get you in the game.
Two Notes Torpedo Captor X
The Torpedo Captor X from Two Notes is a multi-function tool with lots of bells and whistles. It’s a compact and portable reactive load box, amp attenuator, miked-cab simulator, IR loader, and stereo expander. Although I didn’t get to experiment with all of its capabilities, this is a great sounding attenuator—very effective, and it maintains your tone while lowering the volume. But at $599 street, it’s an investment, as are all top-shelf attenuators.
Radial Headload Prodigy
The Prodigy is an excellent sounding box and does a good job attenuating the signal to your speaker. Like the Two Notes, it has more functions than attenuation, but you can choose 100 percent, 50 percent, or 25 percent attenuation. It includes a DI and nice high and low EQ controls—along with a built-in headphone amp. The Prodigy uses custom ceramic-coated resister coils to convert the excess power from your amp into heat. And like the Torpedo Captor X, it’s priced at $599 street.
Dr. Z Brake-Lite
This attenuator from amp-builder Dr. Z sounds great and does a good job of maintaining sound and tone while lowering the volume of your amp. It’s very simple to use, with a 5-position switch for different amounts of attenuation. This box accepts 4-, 8-, or 16-ohm loads. It has parallel speaker outputs, letting you run multiple cabinets. It’s only compatible with tube amps up to 45 watts, so it won’t work with your Marshall stack. But this device packs a lot of bang for $399 street.
Universal Audio OX Amp Top Box
This is the Cadillac of attenuators—a very high-quality device using premium analog components. In addition to a top-notch attenuation circuit, the OX Box features Universal Audio’s Dynamic Speaker modeling technology, giving you access to dozens of spot-on mic and guitar cabinet emulations. But like a Cadillac, it ain’t cheap, at $1,499 street. PS: If you’re a Buddy Miller fan, the OX is an important component of his tone.
What I discovered in my hunt is that if you’re looking to maintain your tone at lower volumes, you are probably better off spending more on an active attenuator. Passive attenuators tend to change your tone while bringing your volume down. So, if it’s within your budget, it’s worth paying more for the good stuff.
Ultimate Attenuator brings your loud tube amps to reasonable volumes
We are very fortunate these days in the world of getting great tone. It has always been a bit of science mixed with art, and occasionally a bit of mojo thrown in for good measure. Now we have at our disposal some great tools to make this job easier. The Ultimate Attenuator is certainly one of these tools.
A bit of history
For years, we have all known that turning up the amp and driving the tube power section harder will produce some great overdrive and distortion tones, as well as those on-the-edge clean tones we all love for Blues and Country music. The first attenuator devices appeared in the seventies. They weren’t much more than a resistor used to convert some of the amp’s power into heat. They did work, but provided what is called a resistive load to the amp. A solid non-changing load on the amp’s output did not allow the amp to “breathe” as it went through the many different frequencies it was called on to produce. This often caused amp failure. Marshall amps in the late seventies even came with a white paper tag on the handle that stated, “warranty void if used with attenuation devices.”
A few years ago a new breed of attenuators was born: reactive load attenuators. There are a few very fine units of this type on the market right now. The bottom line, however, is always “how does it sound?” There are two common complaints. The first is that it changes the tone, and the second is that it changes the feel and dynamics. The first complaint is not what it seems. I could go on and talk about the Fletcher Munson Curve, which is the way our ear perceives tone at different volume levels, but there isn’t enough space here.
The Ultimate Attenuator is the first unit to use its type of design to lower volume. A reactive load is provided that doesn’t need to have an impedance selector switch on the unit. It works well with all impedance settings. What makes this even more interesting is that if you do have an amp with selectable impedance, changing the settings will produce different responses. These will vary both in tone and feel. I have been using one of these units for quite a while with several types of amps, and have had no problems or amp failures. I am not aware of anyone else having any either. So, I have to say that it is very reliable.
The attenuated signal is sent to a very remarkable, 100-watt even response amplifier in the Ultimate Attenuator’s chassis, with a volume control for the unit, so as you turn it down there is no change of resistance to cause a change in tone and dynamics. Instead of using graduated notch settings as on some other units, it is a smooth taper, bringing the level to exactly where you need it to be.
The unit is very well constructed and does come with some very cool options, such as a “Plexi” switch for changing top end response. There is also an optional 100-volt output power plug in the back, which cuts the input voltage to your amp to only 100 volts, as with a Variac. This starves the amp and produces a bit more compression and harmonics. It works very well with an older non-master volume Marshall amp. Think brown sound. Although my unit did not have this option installed, there is also a “bedroom switch” available for extremely low volume settings that still retain the tone.
Once again on the subject of very low volume: remember that the attenuator is basically used to get the amp down to a useable room or club volume. If you turn the volume of the unit all the way off and then bring it up in very small increments so the sound barely comes out of the speaker, you’re not using the unit for what it was designed to do. It is always helpful to push your speaker a bit. The maker, Mark Gregg, is very easy to communicate with, and he has some very special surprises coming up for us in the future.
The Final Mojo
I find the Ultimate Attenuator to be the most transparent unit I have heard. It most reliably reduced the volume without changing the tone, keeping in mind the above-mentioned curve. It won’t harm your amp, and it is very reliable.
Buy if...
you''re looking for a way to harness that big or medium wattage amp and make it useable at normal loudness levels.
Skip if...
you have a transistor amp, as it is not recommended for solid state amps.
Rating...
Base Price $449 As Reviewed $699 - Ultimate Attenuators - ultimateattenuator.com |
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