Magus Innovations’ “The Ultimate Attenuator”

When any new product comes out that takes an interesting new twist on a design, it of course always piques my curiosity to check them out. I was recently contacted by a new maker of a device called "The Ultimate Attenuator" that falls into just that category. If you’re unfamiliar with power attenuators, they simply enable you to take the signal of a fully-cranked tube amplifier and then bring the volume levels down to those necessary to play in various club/rehearsal environments – and some designs can power down to bedroom levels as well.

We’ve checked out two different attenuators already including the well-known THD Hot Plate as well as the Weber MASS and both performed very well. The makers of these products strive for the best transparency and non-coloration possible and that’s no different with the "The Ultimate Attenuator." Both the Hot Plate and the MASS seemed to each have features that made one not superior to the other, but depending on the final application desired, could make the final user lean one way over another when selecting the right unit for them.

The maker of "The Ultimate Attenuator," Mark Gregg, came to me with a strong claim that his unit would be the most transparent attenuator that I’ve ever tried. Quite a bold statement to make, especially since he knew that I was very familiar with the various attenuator options out there!

The Ultimate AttenuatorNot yet in full-finished production, the unit I received was an early prototype built in a typical vented box enclosure. What’s inside however, and how it works, are both quite unique. First off, the concept behind "The Ultimate Attenuator" is to provide a signal load for the amp that is easier on the amp’s output transformer circuit. In this regard, "The Ultimate Attenuator" can accept signal loads of 4, 8, or 16 ohms from an amplifier as its internal load is set to approximately 30 ohms. The tradeoff is some power loss, but since the objective is to reduce volume output and attenuate, in theory, it essentially becomes a non-issue. More on this in a moment.

Also included with my test unit is a three-way switch on the front panel for high-boost, neutral, or low-boost settings. A knob to control the amount of high-boost sits to the right of the switch. Two switches on the back control a presence circuit as well as the ability to bypass the unit completely. Input and output jacks are on the back to hook up the unit in between an amplifier and its cabinet. My test unit did not include a direct out jack but I was told that the design engineer is working to implement that into the final design.

"The Ultimate Attenuator" will work with amplifiers up to 100 watt in design and employs another interesting user options as well. It has a 90 volt tap and output plug from its internal power transformer so that one can power up and plug in their amp as if it was on a Variac set to 90 volts!

An attenuator with a power supply? What’s that all about? That’s where the really interesting part of the design comes into play – the unit’s loaded signal from the amp then serves as an input to an active-powered amplification circuit inside "The Ultimate Attenuator" which then transfers the final powered signal to the speaker. One continuously variable volume pot on the outside front panel controls the final output volume and can go from completely off to full power and everything in between.

The Ultimate AttenuatorThe concept itself is similar to the early Edward Van Halen type of a setup that we featured earlier at LegendaryTones where his Marshall amplifier was first put through a dummy load, then re-amplified through a power amplifier to his final speakers. In this case however, it’s all in one box!

But enough about the features, how did the prototype of "The Ultimate Attenuator sound"? Quite well, I’m happy to report – In fact, I was very impressed. The hardest test sonically for an attenuator is to listen to it at lower "bedroom" levels. My previous favorite in this environment was the THD Hot Plate – at the Hot Plate’s –16 dB setting, the bass notes can get a little bit fizzy or lose a bit of clarity – remember the Hot Plate (or any device for that matter!) is absorbing a tremendous amount of energy from the amplifier and so –16 dB is not a setting I would typically use – I’ve always felt that it’s better to use a bedroom amp for a bedroom application after all. But in the case of "The Ultimate Attenuator", the tone and clarity of the guitar was very apparent at even the lowest of settings. Low notes rang without any "fizz" and as I turned up the volume control louder on the test unit, it continued to work consistently with excellent transparency. Was this indeed the most transparent tone I’ve yet heard? Yes, I would agree with that.

The presence circuit located on the back of the unit worked well to bring out a very mild hint of brightness, while the treble boost circuit gave me more than I could use really. My personal preference while testing the unit through an assortment of Marshalls and Hiwatt amplifiers was to keep the tone switch in the neutral position. At low volumes, neither the bass or treble boosting was needed to my ears but then again, everyone’s setup is going to be different.

How about low points or suggestions? As I mentioned earlier, "The Ultimate Attenuator" uses a 30 ohm load so that power is reduced somewhat regardless of the amp you’re using*. Sonically, this resulted in just a hair less distortion than what I would otherwise hear from my ’72 Super Lead when directly comparing it to my Hot Plate or playing full-out with no attenuator. It’s not a large difference, and I imagine that with "The Ultimate Attenuator", many people would gladly trade off a little bit of the final gain in exchange for having the note clarity especially in the bottom bass frequencies that the unit exhibits.

My only other suggestion is that it would be nice to incorporate an additional switch to separately boost either the bass or treble frequencies as needed. Again, I found that I did not need to use any of the e.q. circuit but others may enjoy the option.

All in all, I think "The Ultimate Attenuator" is going to be a winner of a product when it goes out in full production later this year. Currently in the final phases before production, Mark Gregg has some final-circuit prototype units available for sale with various options and he can still have units built by hand for those interested. Prices are $349 for the basic unit. Mr. Gregg can be reached by phone at 760-799-2453 or via e-mail at [email protected]. The official site is at

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