Posts Tagged ‘guitar attenuator’

Ladies and Gentlemen! Welcome to the bout of the century! A truly momentous occasion in the vein of David versus Goliath! In the red corner we have a Goliath, the reigning King of Attenuators, the Ultimate Attenuator; self-proclaimed King of Transparency – Guaranteed! In the blue corner is the Aracom Power Rox PRX150-Pro, a virtual David, armed with only a transparency sling ! And here’s the opening bell!

The Ultimate Attenuator strikes first, tongue lolling, with bombastic claims of pure transparency. The agile Power Rox ducks, and moves away, its sling of true transparency whirring rapidly. Wait! It launches! It strikes the Ultimate Attenuator square in the head. It’s going down! Oh the humanity! Oh the humanity! The match was over before it was even begun!

I had the great opportunity this evening of testing the Aracom Power Rox and the Ultimate Attenuator in a head-to-head shootout to determine which was the most transparent attenuator. As you can tell from the somewhat facetious and fictitious pseudo-boxing match, you know who won: The Aracom Power Rox PRX150-Pro. Folks, it wasn’t even a contest. Even at the lowest attenuation levels, the Power Rox swept the floor with the Ultimate Attenuator!

My Test Procedures

Equipment: My test was conducted using a Replica JTM45 equipped with original Mustard Caps and a pair of  KT-66’s, into a 4 X 12 cabinet equipped with (2) Original 55Hz Greenbacks and (2) Custom Weber (75Hz) Greenbacks, with a ‘Gibson 57 Les Paul Historic Goldtop as my test guitar.

Clean Test

First, I started with the amp totally clean. I strummed a simple chord progression to get my base tone. Setting the Ultimate Attenuator at about half “volume,” I activated it. I immediately noticed a distinct loss in both highs and lows, as even at minimal attenuation, the bandwidth of my tone was severely narrowed. The full bottom-end and sparkly top-end of my clean tone were significantly reduced. The tone wasn’t that bad, mind you, but it certainly lacked the richness of my base tone – it sounded flat.

One thing that really bugged me was activating the UA, which required a strumming the guitar, then switching on the UA, as if the UA needed a signal to pass through it to even start working. What a pain! It’s amazing that users would even tolerate this.

I repeated the same test with the Power Rox, setting it at half attenuation on the 6-way switch. The result was a reduced volume, but no loss of bottom- or top-end at all.

Clean Test – Bedroom Mode

Same test as above with both attenuators. With the Ultimate Attenuator, can you say “tone sucker?” The tone was not at all pleasing! Even more narrow bandwidth, and non-existent dynamics. There was nothing even remotely good to like at this level with the UA. How the UA website can claim to be “the most transparent and safest tube amplifier attenuator on the market in the world. Guaranteed” is beyond me. Even my old Dr. Z Airbrake sounded better than the UA. So again, at this level, the Power Rox just kicked ass. Lower volume, but full retention of bandwidth and dynamics.

Dirty Tests

In my dirty tests, I ran the amp in its drive channel cranked up fully. 40 Watts through a 4 X 12 is LOUD!!! Especially when you’re standing right in front of the cab! Actually there’s nothing like feeling the SPL’s with an amp full-out! I ran the same tests as I did with the clean channel with both attenuators, and as expected got the same results: The Ultimate Attenuator really sucked my tone, while the PRX150-Pro retained tone and dynamics at all levels. The Plexi switch just made the tone even worse, acting like a treble booster, which made an already horrid tone even worse by just upping the highs. The tone was akin to an old transistor radio played at the volume of a loud TV. Not pleasing at all, and actually, it was a bit annoying, like cats screeching! YUCK!

The Power Rox, on the other hand, again just reduced the volume. The tone remained rich and full, and all the overtones and harmonics came through. It’s amazing what those subtleties do for your tone. You really miss them when they’re not there, as they provide depth.

It’s evident that the Power Rox’s Speaker Reactance Thru technology is far superior at any application. For me, the Ultimate Attenuator company can make all the claims it wants about transparency, but that’s all they are: claims. And while it doesn’t sound all that bad at low attenuation levels, the marked difference in tone between the UA and Power Rox at any attenuation level relegates the UA – at least to me – to the junk heap. You couldn’t get me to put this in my rig if you paid me.

I realize that the UA was the best game in town for quite awhile, and I am sure that at the time it came out, it outperformed the THD HotPlate, which I have also tested, and didn’t like. I also realize that I’m being fairly harsh – much more harsh than I’ve ever been with a product – but all the claims of the UA being truly transparent are mere exaggerations, and not backed up by any discussion of its technology. In fact, all the hyperbole surrounding the UA is quite irritating!

If you knew what went into a UA, you’d have serious concerns, not the least of which is the 32 ohm fixed resistor, which essentially flattens out your impedance, and creates a mismatch so high that you could fry your amp! Adding insult to injury, the solid-state amplifier is what is really running your speaker. Transparent? Hell no! Not electronically, and definitely not audibly.

And mind you, I’m not the only person who feels this way. One new PRX150-Pro user, who is also a former UA user was so impressed with the Power Rox and disgusted by the UA’s tone compared to the Power Rox, that he bought two Power Rox’s! That says quite a bit.

For more information about the Aracom Power Rox PRX150-Pro, visit the Aracom Amps PRX150-Pro product page!

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5 Tone Bones - Gear has stellar performance, value, and quality. This is definitely top of the class, best of breed, and it's a no-brainer to add this to your gear lineup!
Aracom Amps PRX150-Pro Attenuator
Aracom Power Rox PRX150-Pro Attenuator

Summary: This is hands-down the best attenuator on the market! I’ve played a lot of attenuators, and no other has been able to retain tone and dynamics at high attenuation levels as the Power Rox!

Pros: The Power Rox isn’t just an attenuator. It packs extra features that’ll just blow you away, making a it versatile part of your stage or studio rig!

Cons: None.


  • Rotary Switch provides (6) Step Attenuation Levels, plus
    the Variable Mode allows continuous variable control of “bedroom” level adjustment
  • 33dB attenuation range
    * Attenuates 100 watts down to well under 1 watt (0.05 watt).
  • 150 watt (continuous average) power rating
  • Independent Input Impedance Switch: 2, 4, 8, 16 ohm
  • Independent Output Impedance Switch: 2, 4, 8, 16 ohm
    * Uniquely allows mismatched amplifier and speaker impedances to be used.
  • Attenuator Bypass Switch
  • Load Mode
  • Line Out with Level Control
  • 2 Speaker Jacks (wired in parallel)
  • Passive design, does not require AC power
  • Rugged, black anodized aluminum housing
  • Heavy duty, steel reinforced handle
  • Handwired and Handcrafted in the USA.

Price: $649 direct

Tone Bone Score: 5.0. Jeff Aragaki of Aracom Amps never ceases to amaze me with the stuff he comes up with! This time, it’s an attenuator invention that blows away the competition in safety and tone and dynamics with its patent-pending Speaker Reactance Thru (SRT) technology, plus extra features that make it unmatched in versatility and usability.

I’ll admit it: As much of gear nut that I am, I’m also a huge techno-geek. I dig new technologies and the engineering behind them; and when someone comes up with some new approach to something, with completely awesome engineering, it’s hard to control my GAS. I just have to have it.

I recently took delivery of a brand new attenuator invented by Jeff Aragaki of Aracom Amps, called the Power Rox PRX150-Pro. This, by far, is the best attenuator I have ever used, and will be a fixture in my rig for years to come. That’s right. This will always be in my chain. But not just because of its ability to transparently attenuate an amp signal. This attenuator has features that no other attenuator has such as two speaker outs, and a Line Out that you can use to go direct into a DAW, or even another amp! Talk about versatility. Not only that, because you can match impedance in both the input AND the output, combined with Jeff’s patent-pending Speaker Reactance Thru (SRT) technology, you can squelch down the power of your amp and not worry about ever blowing our your tubes and ruining your amp. The SRT technology just kicks ass!

Talking the Talk AND Walking the Walk: Speaker Reactance Thru Technology

Jeff is a very humble man, so he’d never say anything like this, but I’m not nearly as humble, so I will say it: There’s not a better attenuator than the PRX150-Pro. Even if Jeff didn’t include all the extra features you get with the Power Rox, this attenuator simply kicks the shit out of all the attenuators I’ve ever tried – and I’ve tested several, including the Ultimate Attenuator that seems to be the most popular attenuator; and with respect to safety, tone and dynamics, all others simply pale by comparison.

Where other manufacturers make bold claims (read: brag) about their attenuators’ transparency, not only can Jeff Aragaki make the claim (in his quiet and humble way), he backs it up with detailed discussions of his SRT technology and the engineering behind it and what makes it so transparent. Jeff’s SRT technology is absolutely incredible. At any level of attenuation, the Power Rox retains your tone and dynamics. This is because instead of just dealing with amp power reduction through a series of resistors or a dummy load, which also have the added effect of flattening out the impedance curve and changing tone, the SRT technology ensures that reactance between the amp is maintained throughout the entire spectrum of attenuation; hence, the name “Speaker Reactance Thru.” This means that the impedance curve is kept intact so that the continuity of reactance between the speaker and the amp are maintained. Jeff discusses this in a detailed article about the advantages of the PRX150-Pro.

Let’s talk a bit about safety…

As I mentioned, the PRX150-Pro will not burn out your amp. You can crank your amp up all the way, getting that wonderful power tube drive, and not worry about your amp blowing a tube, or worse yet, frying some circuits from flyback voltage. We’ve all heard the horror stories about people using attenuators, cranking their amps, and blowing power tubes. A lot of this has to do with impedance mismatching. Some manufacturers have added options to match impedance from one direction, but the Power Rox has impedance matching in both the input and output jacks! But the point of this is that with impedance matching on both sides, you don’t have to deal with any type of mismatch. That is very comforting to know.

I’ve actually been playing with the Power Rox for the last couple of months regularly before it hit the shelves, and to date, I haven’t had any power tube problems. And we’re talking running my amps down to less than a watt for a few hours straight. I could never do that even with my Dr. Z, which is one of the more safe products out there. I’ve burned out power tubes using my Dr. Z by cranking power too much. It’s not pretty, and I’ve been lucky so far that only my tubes got burned out. It could’ve been a lot worse.

This ain’t yer Daddy’s Buick…

When Jeff first spoke to me about the Power Rox, I thought, “Okay, it’s another attenuator. I’m sure it’ll be great considering what a whiz Jeff is…” But when he delivered the unit, I couldn’t believe what he had added! I was already impressed that it had both input and output impedance matching. That was simply awesome. But he added some awesome features that I was not at all prepared for:

  • Bypass Switch – This is a mechanical bypass that completely bypasses the attenuation circuit.
  • Line Out – This one thing is just so cool! I used it to go both direct into my DAW, and also used it to re-amp into my Hot Rod Deluxe! Talk about versatility! For a test, I ran a cable to my 1 X 12 cab, then ran another cable to my Hot Rod. I could’ve easily just run direct into my Hot Rod without going out to another speaker as well, but you can see how useful this is. I could get my amp’s tone and combine it with the Hot Rod’s tone. So cool!
  • Two Speaker Outs – This is yet another cool thing. You have multiple cabs that you want to drive with a single amp? This makes it easy.
  • Input AND Output Impedance Matching – No other attenuator matches impedance in both input and output, but the Power Rox has it. It’s all part of the package to ensure continuous reactance between the amp and the speaker.

So as you can see, the added features make this oh so much more than just an attenuator, and it’s a testament to Jeff’s creativity!

The proof is in the pudding…

Unfortunately, doing sound clips of an attenuator’s effect is fruitless, because it is difficult to hear the changes, and moreover, it is difficult to describe the change in dynamics on a recording. However, the Power Rox was tested side-by-side to a number of popular attenuators, and even at low levels of attenuation, compared to Power Rox, all the other attenuators had an effect on tone and dynamics. To date, several people have performed head-to-head comparisons between different attenuators and the Power Rox, and they all come to the same conclusion: The Power Rox is truly transparent; not just the most transparent of the lot, but truly transparent. To me, this box sets the standard by which all others must be measured now.

I used my own transparency test procedure to compare attenuators, but Jeff has also provided a very detailed, and in-depth transparency test that you can view on his site.

I know, I must sound like a twitterpated schoolgirl with how I’m raving about this product, but for the very first time, I’ve been able to record my amps fully cranked without pissing off my family and neighbors, and more importantly, without having to worry that I’m going to blow a tube. Even with my Dr. Z, I’ve had to settle with less drive on my recordings for fear of burning out my amps. But with the Power Rox, I can crank my amps and get that wonderful power tube drive! And even better yet: I can trust that my tone and dynamics will not change, no matter the volume!

For more information on the Power Rox PRX150-Pro attenuator, go the Power Rox Product Page!

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PRX-front-543You ever have an itch you can’t scratch? Well, it has been like that keeping my mouth shut about the Power Rox PRX150-Pro. Ever since I played with the early prototypes, I’ve been completely blown away by this attenuator! This is a totally new take on attenuator technology, folks, and I’m hoping it takes the industry by storm. Why? Simply because what we’re talking about with the Power Rox is true transparency in tone when this is in your signal chain; not “almost” transparent, but truly transparent.

Check out the Power Rox PRX150-Pro page at Aracom Amps!

Most comparisons between attenuators revolve around what’s the “most transparent” attenuator, indicating that really none of them are transparent, so people pick the best of the lot. And frankly, I’ve tested out several attenuators and ended up with the Dr. Z Airbrake, as I felt it was the most transparent out of the ones I tested. But nothing could have prepared me for the transparency of the Power Rox.

I could go on and on, but I won’t. In fact, I had already written a significant amount of text, but decided to just point you in the right direction. Go to the product page. Read through the product description, but more importantly, read the supplementary documentation behind the links at the bottom of the page. Jeff Aragaki has graciously provided some very in-depth articles on how attenuators work, and also provides a high-level explanation of the technology behind the PRX150-Pro.

Other manufacturers may brag about the safety and transparency of their attenuators, but none is willing to back up their claims with the engineering behind their attenuators (and if you knew what some were doing, believe me, if you care about your tone and the safety of your amp, you’d get worried). If you’re interested in or even use an attenuator, you owe it to yourself – and your tone – to check this unit out!

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This piece of gear is so new, it’s not even in production yet, but I just had to share the news!

A few months ago, I was watching a video on YouTube about the Faustine Amps VT-58 amp, which is based on the 5E8A “Low Power Twin” circuit. Very nice, compact amp. But that’s not the story. Faustine is just about to debut a standalone version of their built-in attenuator.

One thing to note about Faustine amps is that all models have a built-in attenuator that gives you from -3dB down to -18dB attenuation. I played at VT-57 at Tone Merchants, which is a 35Watt, 3 X 10 amp – classic, sweet Tweed tone. But it was the built-in attenuator that really sold me on the amp, and actually one of the things that started me thinking about using an attenuator in the first place. As you know, I ended up going with a Dr. Z AirBrake, which has totally served me well, and will continue to do so in the future, but I remember the attenuator working so well on the Faustine, that I was wishing that Faustine had a standalone attenuator.

My wish has been granted.

If you watched the video (and I will present it in its full glory at the end of this entry), the reviewer mentions it being released in early 2009. That prompted me to contact Tim Gregoire, Faustine Amps designer and owner to see if and when it will be released. According to Tim, full production models will be available by the end of this quarter or early next quarter. He’s currently building a set of pre-production models for select clients in the SoCal area, and once he’s done with those, he’ll begin production of generally available models.

So what’s so special with this attenuator? From my personal experience with the built-in one, the attenuator circuit Tim has created is totally transparent – at any level. While I love my Dr. Z, at high attenuation levels, it starts sucking tone, and that’s not good. But with the Faustine, I didn’t detect any tone loss, even when I cranked up the attenuation to its highest setting!

According to Tim, the standalone model will have a wider attenuation range than the built-in attenuator. He shared that it will attenuate within the range of -2dB all the way down to -26dB – that’s conversation-level! Freakin’ awesome! No price yet, it probably won’t be cheap. But sometimes you have to pay for transparency. Once out, the unit will be sold exclusively for a time through Tone Merchants. Stay tuned, as I will hopefully be able to get a unit to review!

Here’s the video of the VT-58. This is a great little low-power amp, with wonderful, vintage Tweed goodness!

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