Posts Tagged ‘attenuators’

DualRoxI’ll say this first: The Aracom DRX power attenuator is everything a power attenuator should be!

Biased? Perhaps. After all I’ve made no secret about owning and preferring Aracom equipment, and Jeff Aragaki is a good friend of mine. But irrespective of my ownership of Aracom products and my relationship with Jeff, if you’ve followed this blog with any regularity at all, I don’t say things like that lightly. There’s too much competition in the marketplace to crown a “best” or make a claim like I just did without experience. Luckily, experience is on my side, and having kept tabs on the various attenuators that have hit the market over the years – especially the last few years – I can confidently say that no other attenuator on the market does what the DRX can do.

I was going to save this for the end, but yes, it’s bye-bye PRX150, once Jeff finishes construction of a DRX for me. But I will say this: For basic attenuation requirements, the PRX line of attenuators are fantastic. My PRX150 has been a stand-by on stage and in the studio for years, and has served me quite well. The totally transparent passive attenuation technology combined with the Aracom input/output impedance matching that Jeff invented has no match on the market. And if what you’re looking for is straight-up attenuation, you can’t ever go wrong with a PRX attenuator.

Every year, I write an article on game-changers for me. The PRX150-Pro has always made the list because I just can’t do without attenuation and get the high-gain sounds I need at a reasonable volume. But the DRX will unfortunately AND fortunately supplant it on the list.

So, with the preamble out of the way, let’s get down to brass tacks…

In evolutionary science, there’s a term called “disruptive selection” (aka diversifying selection) wherein extreme traits are selected over intermediate traits within a given population. A good example of this is the evolution of the peppered moth in England (yeah, I was a biology major at university and genetics and evolution were part of the curricula). In this study, the light-colored peppered moth population was severely decreased due to predation; in large part because of the environmental changes brought on by soot covering the foliage, thus making the moths stand out. On the other hand, dark-colored moths increased in population because they could conceal themselves much better against the darker foliage. Darwin also observed this on the Galapagos islands with the finch population (this is a cardinal case, as it is known, and it is mentioned in the article to which I provided a link).

So what does disruptive selection have to do with the DRX? Well, first we have to start with the PRX. Jeff’s attenuation circuit technology, while functioning in basically the same manner as other attenuators; that is, attenuating output power was actually a disruptive event in attenuator technology when it first arrived on the scene. Every other manufacturer at the time was basically using a variation on the same attenuation technology which, while effective, were tone sucks. So to get their transparency, they had to add EQ circuits to compensate for the high-end frequency loss inherent to the traditional attenuator design. Jeff, on the other hand, figured out circuitry that retained transparency and dynamics without the need for an EQ circuit. It truly was a game-changer, and sparked some heated debate on the forums. But with time, things settled down, people picked their attenuators, and the discussion moved on. Enter the DRX (I really wanted to say “Dragon”).

I had worked with a prototype of this a couple of years ago. It was on a pine board. 🙂 And even at the time I told Jeff that this was going to change everything in the attenuator market once he came out with the real deal, and now that I’ve had a chance to finally play with it, I wasn’t wrong. This attenuator changes everything for me!

I finally got to try out the DRX at Jeff’s workshop over the weekend. I was taking my PRX150 in for a bit of servicing because after hundreds of hours of use, I started noticing some weirdness in it that I wanted to have him check out. Also, Jeff wanted me to test a VERY special, new 100-watt amp that he was shipping to Australia before he packed it up. This amp will be his flagship 100-watt Marshall-style amp. I say “Marshall-style” because it has circuitry in it that will give it voicing for three different Marshal amps: Plexi 100, Plexi PA, and JCM800 – all in one amp! It’s absolutely killer, and I will be writing a review of it in the coming weeks.

After I played with the amp for quite awhile, Jeff hooked up the DRX to show that to me as well, then spent several minutes explaining its operation to me. As I listened to him, I started chomping at the bit to test it because it had everything that I had wanted in the PRX150! I also knew that based upon my experience and knowledge of other attenuators on the market, the DRX would be an ass-kicker.

I won’t bore you with technical details, as this is an “impressions” article, so you can read about the features here. But I will highlight the three most major features that get me so excited about this attenuator:

Dual-level attenuation. For clarity, Jeff has this labeled “boost” on the attenuator. But it’s not a boost in the traditional sense in that it doesn’t add input gain to your signal, which would result in a bit more compression from the power tubes. This is actually an attenuation reducer. In that sense, it is a boost as output power increases and you get more volume. But unlike input boost, no compression takes place, thus your tone stays the same. This is an absolutely HUGE feature for me, especially when I’m playing in overdrive and need to get into a lead break. If I’m already slamming my amp with input gain and my tubes are pretty well saturated, adding more input gain to do my leads doesn’t change my volume much. But with a “boost” mode on the attenuator, I can reduce the attenuation to increase the output power at the back-end of my amp and will get the volume boost that I need. Then switching back to “normal” mode, I can easily go back to rhythm volume.

This is the very first feature I tested on the DRX, and that feature alone sold me on it, and I asked Jeff if he’d build me one. This is something that I’ve wanted on my PRX150. The secret behind this feature is the foot switch; actually foot switches available for the DRX. I won’t go into detail about them here – because I only know about what mine does – so you can read about what each different type does here. I have a “Type B” foot switch which allows me to not only switch back and forth between normal and boost modes on the attenuator, but also allows me to switch channels on my two-channel amps. I could actually use this on my DV Mark Little 40. While it’s not a two-channel amp, the foot switch provides 6dB of gain boost. So I could have the amp set up in normal mode at just the edge of breakup, then when I engage the “boost” on the attenuator, I’ll simultaneously add the 6dB boost on the amp to take it over the edge.  OMG! Looks like I’ll have to test this. 🙂

You might be thinking “so what” about the foot switches. Well these are what set the DRX apart from the competition. Actually, you could do without a foot switch and in that case you’d have to switch between normal and boost by hand; still much more than what the competition offers. But combined with one of the Aracom foot switches, it suddenly opens up a bunch of possibilities, and further distances the DRX from the pack.

Variable Dynamic Control. As if Jeff’s attenuator technology and dual-level modes weren’t enough, Jeff added another feature to the attenuator that to me, simply decimates the competition. VDC is a subtle feature (actually less subtle if you switch back and forth between extremes) that adjusts the reactance between the DRX and the speaker. The result is a smoothing out of the high-frequencies as you change the reactance. This is NOT an EQ, but it does act like a very subtle high-cut filter. For instance, when my Plexi-style amps are cranked, they produce a ton of bright tone (and no, I’m not talking about those undesirable high-end transients that some in the past have imagined hearing – I think it’s their tinnitus. 🙂 ). With the VDC, I can roll off a bit of that so my tone isn’t quite as piercing. In my test of the DRX, we had the 100-watter cranked in the Plexi channel with minimal attenuation (oh yes… it was LOUD). With Jeff moving from extreme to extreme, the sound went from piercing (no roll-off), to much smoother. The sweet spot for me was a couple of clicks down on that amp.

Why is this an important feature? One of the complaints that people had about the PRX line when it first came out was that when they cranked their amps, they’d hear these high-end transients or their sound was piercing. I don’t think they ever totally cranked their amps up before. A cranked tube amp takes a little getting used to because it transforms at higher-gain, with many amps seemingly producing more highs when cranked (or they’re just not as apparent when slightly overdriven). For some like me, I love those high-frequencies. But for others, they’re undesirable. So now, those complainers have nothing to complain about. If they don’t like all the highs their amp is producing, they now have a way to dial them down; without adjusting the EQ on their amp! How f-in’ cool is THAT?!!!

It only weighs 7 lbs!!! As much as I love my PRX, it weighs 18 lbs, and is about the height of an amp head. The DRX, on the other hand weighs less than half that, and has a lower vertical form factor than the PRX, making it much more easily transportable. For as much I gig, the less weight I have to lug, the better.

I could go on and on and on, and it looks like I’ve done a good job of that already. 🙂 But the DRX represents yet another turning point for me. I will be releasing gig reports and a studio test (with clips) in the near future. Jeff graciously lent me his first production model while my DRX is being built. Stay tuned!

For more information, check out the DRX product page!

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PRX-front-543Ever since I started this blog, I’ve talked about attenuators, and how they’ve enabled me to get tones out of my amp at reasonable volume levels that I could only previously get at super-high volumes. But before I get into the discussion part of this article, take a listen to this clip (it’s the same clip I recorded with my previous article on the Mullard ECC83):

Here are some details about the recording:

  • I plugged directly into my Aracom VRX22, which then fed into my Aracom PRX150-Pro, then out to a custom 1 X 12 with a Jensen P12N
  • The amp was in the drive channel with master at 6, volume (gain) at 6, and tone at 6 (the tone on this amp adds a little gain as well as an edge)
  • The PRX150-Pro was set at maximum attenuation
  • Volume-wise, this was talking conversation level!!!
  • No EQ was applied to the guitar – what you’re hearing is the raw tone.

With respect to “maximum attenuation,” I was in variable mode with the variable sweep pot all the way to its left extent. I shared my amp and PRX settings with Jeff Aragaki this morning, and he estimated that the output power was approximately 0.04 Watt!

Many people are apt to talk about how the speaker needs to move air, and that an attenuator doesn’t allow that to happen. But that clip simply demonstrates that with the right combination of equipment – and in my case, also a great set of tubes – you don’t necessarily need that speaker cone breakup to get great tone for recording purposes. Yes, SPL’s do play a big role in your overall tone, but to be able to achieve the kind of tone I was able to get at that very low volume level is nothing short of amazing!

So what about an attenuator being life-changing?

Maybe that’s a bit strong of a phrase, but ever since I’ve been using attenuators, and especially since I’ve gotten my Aracom PRX150-Pro, I’ve been able to explore tonal territory that I could previously only achieve using pedals – and only simulating at that! Take overdrive pedals for instance. If you’re a regular reader of this blog, you know I’m crazy about them. I probably will still be nuts about overdrive pedals, but there’s one thing an overdrive pedal can’t do that an attenuator allows me to do, and that’s to get the thick, natural overdrive tone of my amp. Don’t get me wrong, I still use them, but I use them now more for tonal accents to my drive tone rather than giving me my drive tone. That’s very profound; especially for an overdrive pedal freak like me!

Here’s a good example that I just recorded. This clip is part of a new song idea I’ve been playing around with. Setup is pretty much the same as above, but for the rhythm, I’m running Strat into my Kasha overdrive pedal to get a jangly, crisp tone. The lead is Goldie plugged straight into my VRX22. I did mix and do a simple master on the recording, but the guitars were all recorded raw, with no EQ. In my DAW, I added some reverb to both parts and a touch of delay to the lead, but that’s it.

Speaking of pedals, since I’ve started using a high-end attenuator (there are others such as Alex’s and the Faustine Phantom), I’ve actually started using pedals in general much less. I’ve really relying on the natural tone and sustain of my amp. For instance, I’ve found that I’ve only been using reverb in the studio. When I play out, I just don’t bother. In fact, for the last few weeks, I’ve only been taking two pedals to gigs with me: My BOSS TU-2 Tuner and my VRX22’s channel switcher. Same goes with my Reason Bambino.

Life-changing? Probably not, but definitely approach-changing. I may personally endorse the PRX150-Pro, but there are others out there. If you really want to hear what your amp has to offer when it’s fully cranked with the power tubes glowing, then you owe it to yourself to get a good attenuator!

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Aracom Amps PRX150-Pro AttenuatorAs many know, I’m a big fan of attenuators. In the past I’ve owned a couple and have tried out several. And with the addition of the Aracom PRX150-Pro to my rig, I’ve finally got a device that is helping me realize all the tonal goodness my amps have to offer. But this entry isn’t about the Aracom attenuator. There are a few attenuators that have entered the market in the recent past including the Faustine Phantom and others that are having the same effect on axe slingers and how they approach their tone.

So what’s the big deal? Most folks know how an attenuator operates. It sits between your amp and your speaker(s), and squelches the output signal from your amp which results in a lower output volume, so you can drive your amp to high gain levels and not shatter your eardrums. That’s the basic premise behind attenuators in general. But up until recently, attenuation came at a price, and that is the loss of tone and dynamics, or completely changed tone at higher attenuation levels; to put it simply, loss of tonal quality. I’m willing to bet that this very thing has kept lots of people from using an attenuator.

But with the new breed of attenuators hitting the market, loss of tonal quality is much less of an issue, if it’s an issue at all. Now you can bring your output volume WAY down, and be assured that the tonal quality you’ve worked so hard to achieve is still there.

So how will this change the way we approach our tone? I would venture to guess that many guitarists have really never known what their amp sounds like fully cranked up – at least for extended periods of time. Sure, if you’re a pro and regularly play huge venues, you know what it sounds like. But for us mere mortals who rarely play in more than a dance club, we’ve never been able to fully experience the cranked up tone of our amps, and that’s where a great attenuator comes into play.

When I hooked up my PRX150-Pro, the first thing I did was to set it on load mode and turn the variable to full attenuation, then dimed the master and volume on my amp to see what it would sound like. I wasn’t prepared for the onslaught of new tones that were suddenly available to me: rich harmonics, tons of sustain, and incredible touch sensitivity. It was as if a whole new world was opened up to me.

With my old attenuator, I rarely went to real high levels of attenuation because it made my tone sound weak and lifeless.  Plus, I didn’t want to burn out my tubes – which I learned the hard way when I cranked my amp while hooked up to the attenuator. But with the Aracom attenuator, I knew I could crank it as high as I wanted to and still be safe. What this means is that I now have access to a wider landscape of tones and dynamics that I can also safely reach. And that’s another feature of the new breed of attenuators: They appear to be much safer to use than the older designs out there.

Here’s an interesting question I got from a buddy of mine: Will I get rid of my overdrive pedals as a result now being able to get the fully cranked tone of my amp? Not on your life! 🙂 I love how they add color to my tone. But I will tell you this: Now that I can crank up my amp to high gain levels without the concomitant high volume levels, I’m actually not using my overdrive pedals as much. Oh, I still use them because they add certain characteristics that aren’t possible with my natural overdrive tone; just not as much as I used to because when I want just straight amp overdrive, I just crank my amp. But when I want to use them, I run them through the clean channel of my amp that has lots of clean headroom, so I can take advantage of the tone that they offer.

So is it a significant change to how we approach our tone? Possibly. I know of some folks who’ve completely stopped using overdrive pedals altogether as a result of using an attenuator, and use a clean boost or even just their volume knob on their guitar to get the lead volume they want. Me? I like to have a few different “brushes” that I can use to create different textures, but in either case, getting that cranked up tone naturally without shattering eardrums is pretty huge.

I think the folks who will gain the most from these great new attenuators are the home studio musicians. Imagine being able to record a screaming guitar solo, and not have the wife or neighbors yelling at you to turn down your volume! I regularly do my recording into the wee hours of the morning, so having an attenuator has been a godsend. But up until I got my PRX150-Pro, I had to wait to record solos until it was day when I could turn up my amp to a gain level that didn’t get me yelled at, as my other attenuators just didn’t give me the tone I needed at high attenuation levels. Even if I used an overdrive pedal, it doesn’t sound good unless it’s working with your amp and pushing your pre-amp tubes, and that takes juice! With a great, transparent, or non-tone-sucking attenuator, you can push your amp hard, and keep your volume under control!

I know of a lot musicians who poo-poo the use of an attenuator. But an attenuator can do wonders for gigging. Want to make the sound guys happy? Here’s another way to look at it: With an attenuator, you can focus on your tone, and not projecting out to the audience. Get enough volume to hear yourself on stage, then let the sound guys do their thing. PA technology has come a long way since the early days of rock and roll, where amps had to be played loud to get the sound out to the audience. Also, if you think about it, speakers are highly directional. If you want to disperse your sound, use the PA.

There’s been an interesting thread that I’ve been lurking on The Gear Page entitled, “Sound guys think I’m too loud.” Someone suggested early on that the original poster could use an attenuator or a smaller amp to reduce their volume. The suggestion of using an attenuator went largely ignored, but as I followed this thread and read all the various insights, using an attenuator is the perfect solution for this.

I’ve heard a lot of the complaints about attenuators in the past, and I’ve also had my issues with them. But with the new breed of attenuators, tone suck is no longer an issue. And that tonal quality will be sure to change how guitarists approach their performances.

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Aracom Amps PRX150-Pro AttenuatorAracom Amps has just posted a page on their site which features Gene Baker – luthier of the famed Baker Guitars and now of Fine Tuned Instruments producing “B3” guitars – demonstrating the transparency of the Aracom PRX150-Pro Attenuator at various attenuation levels.

Gene has also provided commentary on the recording and how no EQ adjustments were made to the amp – even down to bedroom levels! This is a re-affirmation of what I’ve been saying all along about this awesome device! The PRX150-Pro simply retains the tone you work hard for – no matter how much attenuate your signal; and more importantly eliminating the need to compensate with EQ.

Check out Aracom’s Gene Baker audio page here!

Having someone like Gene Baker demonstrate the capabilities of the PRX150-Pro is huge! Gene is an incredible guitarist!

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I’ve often extolled the virtues of a cranked amp here at GuitarGear.org and elsewhere. My belief is that when you’ve got both your pre-amp and power tubes working, you get the real character out of your amp. There’s something that happens to your tone once you get juice into your power tubes that adds a certain dynamicism and complexity that you just can’t get with just your pre-amp tubes. Unfortunately, most mere mortals, like myself, don’t normally play venues that that will allow us to crank our amps to the point where the power tubes of our amp come into play.

Take, for instance, my good buddy Phil. He’s the lead singer of a bar band called Phil ‘N The Blanks. Up until recently he was playing through a Marshall DSL100 JCM2000 100 Watt head into a Marshall 1936 2 X 12 cab. Talk about too much amp for his gigs! I ran sound for him at a gig a couple of months ago, and could only turn his volume and gain controls to about 3 each before he stepped on the band entirely; not to mention peeling faces off! Since he’d owned the DSL100, he’d never played above 5 because it was way too loud.

Recently, I lent him my Aracom PRX150-Pro attenuator so he could squelched down the volume but crank up his amp. He couldn’t believe his ears! He was finally able to get the gain up in his amp where his power tubes would break up. It was like a completely different amp once he heard the cranked up tone. I had been telling him for months that there’s really nothing quite like a cranked up amp, and for the first time since he owned the amp he was able to hear for himself what I had been talking about. Before that, he was on tonal training wheels! 🙂

Ultimately, he decided against going with an attenuator, but he did a very smart thing: He purchased a low-wattage amp, the Marshall Haze MHZ15 15 Watt amp. It hasn’t arrived yet, but I’m excited for him because he’ll be able to crank that amp at a reasonable volume level, as the lower wattage amp will break up a lot earlier, and he’ll be able to reap the benefits of the response of his cranked amp!

1 Watt is LOUD!

But here’s the funny thing: 15 Watts can still be freakin’ loud when cranked! The following chart shows SPL at 1 meter vs. Wattage (I got this from the Aracom site where Jeff discusses understanding attenuation).



SPL (db)




Passenger car at 10 (60-80dB)





Vacuum cleaner



Major Road Noise (80-90dB)



Noisy factory







Jack hammer at 1m







Accelerating motorcycle at 5m





Hearing Damage (short term exposure)



Rock concert







Jet at 100 meters (110-140 dB)



Threshold of pain

What’s amazing from the table is how loud 1 Watt is at 1 meter! It’s as loud as a jack hammer! And 0.0312 Watt is as loud a vacuum cleaner! Jeff got this information from a well-known study done in 1933 by Harvey Fletcher and W A Munson about human hearing response. For those people who say, “P-shah” to low wattage amps, just reference this chart.

Granted, there is a certain mojo about a 100 Watt amp cranked up – even a 50 Watt amp. But most people other than those playing large venues can crank their amps to experience that mojo. But in spite of that, there’s been a movement in the industry these past few years towards lower wattage amps. I think a big part of the reason for this is the improvement in PA gear over the years. Want to get your sound out there? Mic your amp. After all, all you need is stage volume so you can hear yourself. Let the sound guys project your sound out.

My buddy Vinni Smith of V-Picks does exactly that. As amazing as he is with a guitar, he gigs with a Roland Cube 30! He just gets his stage volume, then has his amp miked to get his guitar out to the audience. This dude gigs alot, and he’s living proof that you don’t need a lot of power to get perform. As long as you can get your tone, you’re golden!

Circling back to the title of this article, there really isn’t anything like the sound and feeling of a cranked amp. Especially with tube amps, when the power tubes have juice, they add all sorts of things to your tone such as compression, a different kind of breakup and even more touch sensitivity. You can get that in a couple of ways:

  1. Get an attenuator. There are several on the market, including the increasingly popular Faustine Phantom, but my bet is on the Aracom PRX150-Pro, as it takes a completely different approach to attenuation than all others. I’ve never played an attenuator as transparent is this.
  2. Get a lower wattage amp. I’m not even going to list what amps to buy as there are tons of fantastic amps – both boutique and mainstream – on the market. Just make sure you give them a listen.

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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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