Published On: December 15, 2014

ATI AT6002 Stereo Power Amplifier Reviewed

Published On: December 15, 2014
Last Updated on: October 31, 2020
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ATI AT6002 Stereo Power Amplifier Reviewed

Jerry Del Colliano reviews ATI's Signature Series AT6002, a two-channel, 300-watt Class AB amplifier that carries an MSRP of $3,995. To say that he came away impressed would be a huge understatement.

ATI AT6002 Stereo Power Amplifier Reviewed

By Author: Jerry Del Colliano

ATI-AT6002-thumb.jpgThere is a wine maker in California known as Jim Clendenen who makes some of most fantastic Chardonnays in the central coast under the brand Au Bon Climat, as well as under his Clendenen Family Vineyards moniker. He is also contracted with legendary wine stores like Wally's Wines to make their house brand. Roy Yamaguchi from the Hawaiian chain of Roy's restaurants has been known to use Clendenen's wines as the restaurant's premium house Chardonnay. He's the star wine maker backing the bars of the best restaurants out there.

Morris Kessler is the same guy for amplifiers. With 50-plus years of manufacturing experience, it could be argued that nobody makes a better amp for the dollar than Morris. Other companies seek out his help with both design and manufacture, including but not limited to the Harman brands, Outlaw Audio, Lexicon, Datasat, and many others over the years. Morris also owns brands like SAE, Theta Digital, and B&K and makes many of their amps.

The AT6002 is Morris' signature stereo power amplifier, rocking 300 watts into eight ohms in a stereo configuration for $3,995. It can be purchased direct or through dealers and/or custom installers. If you need more channels of power, ATI has you covered with the AT6003, AT6004, AT6005, AT6006, and AT6007, which as you may have guessed are the three-, four-, five-, six-, and seven-channel brothers of the stereo 6002.

The AT6002 is a mean amp. Its fully balanced design uses current feedback with a single input stage and dual-differential output stages to increase amplifier speed (slew rate) and reportedly reduce noise by upwards of 50 percent. The 6000 Series amps use dual DC servos to deal with issues of DC offset. You actually have to plug this amp into the wall twice, which you will gladly do when you get your first taste of the sound.

ATI offers a seven-year transferable warranty, which is quite favorable to the consumer. The 6000 Series amps report 0.03 percent THD at eight ohms, 20 Hz to 20 kHz with all channels driven to the max, thus the amp has the headroom for today's best formats, be it Dolby Atmos, HD music files, or uncompressed 7.1 soundtracks from Blu-ray. All ATI 6000 Series amps use dual toroidal transformers, dual power switches, and dual AC power chords, thus they are truly dual mono amps in one chassis. The AT6007 reportedly performs even better when given two unique 20-amp circuits to provide its power. That might be a little bit of overkill for the AT6002, not that overkill ever goes out of style when you are talking about big, audiophile-grade amps.

The AT6002 measures 9.5 inches high, 17.25 inches wide, and 18.5 inches deep, with a 19-inch faceplate suitable for rack-mounting. Under normal circumstances, I'd prefer to bolt the ATI amp right into my rig; however, for this review, I swapped out my measly (it's really not measly) pure Class A Pass Labs XA30.5 amp with the 300-watt Class AB ATI amp in my office rig. The ATI amp powered Focal Diablo Utopia Diablo speakers and enjoyed a signal fed from a Benchmark DAC1 PRE, with sources like an Apple Mac Pro tower, an Oppo BDP-103, and beyond. Cabling was Transparent Reference for analog, speakers, and most digital cables.

The Hookup
Installing an AT6002 couldn't be much easier. Open the box. Pull off the plastic. Be careful not to hurt your back lifting the sucker, especially if it's one of the multichannel amps (the 6000 Series amps weigh between 86 and 136 pounds, depending on the model). Plug in your XLR cables (remember, this is a balanced amp, thus you will want to enjoy it in a fully balanced system), plug in the power cables, attach the speaker cables, and you will be ready to go. I did have a little bit of an issue getting the spades of my Transparent speaker cables into the back of the AT6002, but with a little finesse, I was able to get it going. Top cable companies like Transparent are glad to re-terminate your cables if you make an upgrade to a new amp. Often you just need to send them back, and they will take care of you as your system demands.

Heat is always a consideration with big power amps; but, in this case, I couldn't get the AT6002 to run very hot even under heavy abuse. Perhaps in a more enclosed rack, the AT6002 will run hotter. Compared with other amps in the price category and above, though, the AT6002 runs as cool as a cucumber.

We can and will talk about audio jewelry later; but, when auditioning an amplifier of this classification, you want to get to the listening process as fast as you can. I kicked off my evaluation with "Para Sempre" from the latest Thievery Corporation album Saudade ripped at 1440 AIFF. This fast-paced yet loungy Brazilian-jazz-inspired track jumped right out at me with an immediacy that seriously caught my attention. Bass was well defined. The female vocals were sweet -- not Class-A amp sweet, but 90 percent of the way there. The depth of soundstage was notable. With this much power on 94dB-efficient Focal speakers, it felt like having a V12 power plant waiting for you to stomp on the accelerator. Just give me a second until I pull onto the freeway, OK?

Thievery Corporation - Saudade (full album)

I then evaluated at the AT6002 through what I call "The Jimi Standard" -- that means if a system/component/speaker doesn't sound good with Jimi Hendrix, then it likely sucks and shouldn't be bought. I cued up "Gypsy Eyes" from the Electric Ladyland CD. Obviously, the age of the recording was evident compared with the previous track, but what was notable was the depth of soundstage. Yes, this is a quiet amp, as Morris went to great lengths to refine every detail he could for his reference offering. The result is not only an ability to resolve the excitement of a left-handed Fender Stratocaster played by the greatest guitar player of all time, but also the ability to remarkably reproduce the depth of a recording made during a renaissance period for rock-and-roll music.

Click over to Page Two for more on Performance, plus The Downside, Comparison & Competition, and Conclusion...

Performance (Continued)
Moving forward a few decades to "Sara's Smile" from Hall and Oates' Greatest Hits Rock and Roll Soul (CD, via the Oppo BDP-103), I could hear from the first breath of the track that it was recorded on analog master tape, and that "warmth" was the only noise I heard. Daryl Hall's voice was quickly presented front and center with some of the best imaging I've heard. In comparison with my reference Class-A Pass Labs XA-30.5 amp, the ATI has the Pass Labs beat in the power department and is super quiet, but the Pass Labs amp resolved the xylophone and background strings with more subtlety. When John Oates kicks in with the background vocals, you get a lot of finesse - perhaps some of the closest I've heard under $10,000 from a non-Class-A amp.

Moving to No Doubt's "Hella Good," a more modern track with lots of dynamic range, allowed me to stomp on the accelerator a bit musically. The deep bass notes were extended yet quick. The electronic programming/production, slightly in the background of the mix, resolved itself beautifully, as it's simply obvious that you have such huge reserves of power waiting for you to use and/or abuse whenever you want. The point where other amps fail on this track is the transition into the chorus. That's not the case with the AT6002, as it just sort of laughs off "Hella Good" as being a demanding demo track. OK, you want a fight, I will give you a fight...

No Doubt - Hella Good

I moved on to Pink Floyd's The Wall (disc two in 1440 AIFF from the Mac Pro). On the mysterious "Vera," the openness and quiet of the ATI 6002 was compelling. Roger Water's voice beamed above the gorgeous representation of the musical bed. With the segue into the bombastically orchestral "Bring the Boys Back Home," the AT6002 pretty much said, "Finally, I can stretch out a little bit." The chorus resolved wonderfully over the top of the full orchestra, while Water's vocals remained ever-present. You get both power and finesse with the AT6002 that historically required spending a lot more money to get a top-of-the-line audiophile amp.

Pink Floyd - Nobody Home + Vera + Bring the Boys Back Home + Comfortably Numb

With Transformers on Blu-ray, the scorpion fight scene brings in as much Michael Bay action as you possibly can handle, complete with an automated, pissed-off mechanical scorpion, bomb blasts, thousands of rounds of gunfire, drones in flight, and even a failed call to a customer service agent in India. The spooling engines of the fighter planes sounded energized. The cliché military orchestral music in the background even sounded good. In the cacophony of such an over-the-top bombastic demo, the AT6002 didn't really crack a sweat, nor did it miss a beat.

The Downside
It's time to talk about audio jewelry because, when you get into top-of-the-line audiophile amplifiers, that's part of what you are buying. With the ATI, you are getting the Pontiac Aztek of industrial amp design. It's a black box with Morris' signature and what I think is a pretty bland if not ugly logo. There aren't fancy heat sinks, as the amp doesn't need it. Utilitarian rack handles adorn the front of the amp, and a modest but non-dimmable blue light notifies you that the power is on. The AT6002 is about as plain-Jane as you can get when it comes to goodies, and that's exactly why it costs $3,995 and not $10,000 for the stereo amp.

Does the performance of the AT6002 command a fancier wrapper? Perhaps, but that's missing the point. This is the world's leading contender for a bang-for-your-buck amplifier. It's the type of amp that you put in your rack and control via a trigger, not the type of amp that you park on amp stands behind your speakers. If you want the later, there are a dozen companies that make a 300-watt amp that will meet your needs -- you just might need to spend $10,000 to get your hands on one.

Comparison and Competition
I guess in the world of seven-channel amps, you could compare the AT6007 to the Outlaw Audio 7900, both made by Morris Kessler. In the world of stereo amps, I made a pretty odd comparison to a 30-watt pure Class A power amp from Pass Labs in the XA30.5; but, at $5,500, it's in the price category, and the two fight it out nicely in terms of fine details, despite the fact the Pass Labs amp is a physical beauty in comparison. Krell, Classé, Mark Levinson, and all of the other blue-chip audiophile companies have very worthy offerings, but all are nearly twice the price (if not higher) of the no-frills ATI 6002. From my listening tests of other amps, you have to look to the likes of the Krell 402e or my former reference amps, the Classé CT-M600 mono blocks (man do I miss them) at around $12,000 per pair and packing 600 watts per channel, to get notably more amp. That's a lot more money for the next level up.

A lot of amp designers -- from Dan D'Agostino with the Aragon 4004 to Nelson Pass with the Adcom GFA-555 -- have tried to make the best-value audiophile amp. Today, I think Morris Kessler owns the crown. The AT6002 is one of the most powerful, resolute, quiet, and musical amps that you can lay your ears on, even though you can spend a lot more money on others that go to that next level. Is it time to get carried away and say it's the best amp ever? No, that would be a foolish mistake. What you could say is that, dollar-per-watt, you might not be able to find a better amp today. The AT6002 is a wonderful performer and a stunning value. It is very bare bones yet performance-oriented in its approach, just like the man whose signature is on the front. Don't let the comparably low price fool you, as this amp is for real. Its only real competition are amps from the big boys costing nearly twice the price.

Additional Ressources
• Check out our Stereo, Mono and Audiophile Amplifiers category for similar reviews.
• Visit ATI's website for more product information.

  • AIB
    2015-01-30 10:02:04

    I had the A21 for a couple of months. It will always be matching and prefrences but the A21 went out the door! I have had many power amps since then and I can say the ATI6003 that I have now is with no comparison way better in every way. Ok it has the look but that is also all... In my stereo setup so to speak. (Monitor Audio Platinum PL200)

  • Muataz S
    2015-01-22 11:52:17

    Hi mark, I hope you enjoyed the ati :)

  • markshlitz
    2015-01-22 12:14:15

    Latest, I was told this amp does not need to break in, not true. I found it took around 150 hours to really bring out the sweetness. Stock power cords give you detail, very sharp detail, clear as heck. I thought the detail from my Parasound A21 was good, this is much more detailed and clear. Just sounds like more is there. Imaging is very good. I substituted the stock cords with Jura Supra Power cords. 2 Differences, the image depth. The depth is significantly deeper; front to back. Second much more lush, fuller sound. You can hear the "air" around the voices. Each instrument is better rendered. I had a friend over last night who had a Krell system "till the wife got involved a few years back." He was surprised at the what the amp could do. Comment, Keep the A21's in surround duty, you have a winner there. My son prefered the stock power cord sound, The Supra's for me. Both were very good.

  • markshlitz
    2015-01-10 22:30:54

    The first 30 minutes the highs were a little harsh, that settled down and about the 2 hour mark the bottom end really opened up. So far a clear winner that will drive my front 3 speakers. I also found each not seemed more defined and fuller sounding. Threw on a Beethoven 9th concert and you could pick out the individual instruments. The Parasound was good at that but the ATI seemed to isolate more instruments. I am impressed with the amp.

  • John
    2015-01-10 19:16:31

    Looking forward to what your ears have to say.

  • markshlitz
    2015-01-07 15:19:57

    I have the tracking number and it should be here in 2 days. I figure 3-4 day break-in and we should be ready.

  • Muataz S
    2015-01-07 15:13:32

    Good to see someone have both with Epicon speaker. Waiting for your test :)

  • Timothy Sorrentino
    2015-01-05 19:18:28

    I believe that ATI is made in the USA, whereas Halo/Parasound is made in Asia. Cost of labor! Have you had any chance to compare the ATI to the latest Indy Audio Labs Aragon 8008?

  • markshlitz
    2015-01-04 15:50:04

    Good morning Jerry, As an owner of 2 A21's, an A51 and this Friday a 6003, I am willing to take up the challenge and compare them using Dali Epicon speakers. Looking forward to hearing this amp. I have a 15 and 20 amp line ready to play with.

  • t.j.
    2015-01-02 18:26:09

    Because jets flying above you and rain drops in movies need $5,000 speakers and $5,000 amps....

  • Colonel Gurlukovic
    2014-12-31 19:59:21

    You guys forgot the onkyo m-5000r

  • Botswana Jones
    2014-12-27 20:47:12

    I will have to stick with Emotiva. Great amps for the price. When your talking a a 4000 dinero ATI and a Pass Labs amp that's a whole nother enchilada...

  • Justin
    2014-12-24 20:35:05

    ATI and Parasound talk is like Ford vs Chevy. You're going to have your preference. It's good to see ATI back in conversation. I know they're used in a lot of professional installs and not very publicized to the masses. Not too long ago they were the Outlaw and Emotiva amps of today. Any company that has long term success and stays innovative will increase in cost. ATI is a proven amp manufacture you're going to pay more. But, they're not a CHEAP amp manufacture. I would say they make a premium amp at a competitive price. Remember perceived value. Everything has a perceived value. 300watts into 8ohms is going to cost you, no matter the company that provides it.

  • jerrydel
    2014-12-22 00:12:41

    Boulder is some crazy stuff. Pretty and sounds good too but $500,000 for an amp is a little steep for my tastes. I am telling you - this amp KILLS IT at $4,000. I am likely going to use one for 7 of my 9 channels of Atmos in my theater. Not sure. Might be broke by the time I move in. That's a real possibility.

  • Porscheguy
    2014-12-20 17:30:06

    I think $4000.00 is a good value and I'd love to hear one some day. It's when we get into the Boulder price range is when I really go "gulp"... I have 3 Emo XPR amps that cost close to 6K so I'm not that cheap! :)

  • hifiguy268
    2014-12-18 21:22:41

    I am not questioning ATI's quality. But for a company that is known for quality at a good price point, the 6002 looks to be way expensive. Especially since they jacked up the price $600 since that review was written.

  • jerrydel
    2014-12-18 20:27:06

    You will yell at me for saying a $4000 amp is a value but it REALLY IS. Compare with amps costing $10,000. Sick value. Right up your alley.

  • jerrydel
    2014-12-18 20:26:19

    Both great amp designers: Morris and John Curl. Parasound looks better no question. That ATI is haunting me. I might buy one for 7 channels and do another Pass Labs for my left and right speakers in my pending Atmos theater in my new house.

  • Adrienne Maxwell
    2014-12-18 19:01:08

    The MSRP is $4595, but the selling price is $3995.

  • hifiguy268
    2014-12-18 18:11:52

    I only call 'em as I see 'em. If it was my money being spent, I'd rather spend $5K on a pair of A21, which I would have the options of either 750 wpc (which I don't need) or 4 channels of amplification. Both of those options would not exist spending $4600 for the 6002. I am sure they would be about equal in quality, but for the advantages of the A21, I just mentioned, a no brainer, At least for myself.

  • filecat13
    2014-12-18 17:45:13

    Thanks for your honest response.

  • hifiguy268
    2014-12-18 15:53:37

    I have not heard the 6002. I am looking at the cost/w. And as mentioned below, the 6002 is now $4595. That is almost the price of two A21s. And those A21s can be placed in bridged mono mode providing 750wpc, if one has really difficult speakers to drive. Even if only using a single A21 @250w, I do not see that the 6002 is going to be worth $2100 more. ATI has been said to provide very good quality at a good price...I do not see that being true of the 6002!

  • filecat13
    2014-12-18 15:33:57

    Does your "If I compare..." experiment consist of actually comparing and contrasting the AT6002 and A21 in the same place at the same time, or in comparing them at different places at different times, or does it merely represent your reading of spec sheets and possibly your bias toward the A21 because you've heard and/or own it? If anything but the first, then your opinion has little relevance. If the second, at least your opinion would have some modest standing. If the last, then what's the point? I'm sure Jerry has at least heard both, and he generally has broader experience than most folks.

  • hifiguy268
    2014-12-18 10:58:12

    If I compare the AT6002 @300w/$3995 to the Parasound A21 @250w/$2495, I'll take the A21 every time. I really doubt the AT is a better amp than the A21, to say nothing of the extra $1500. I don't see how anyone can call that AT6002 a good value. And the Parasound Halo series amps just look better!

  • heavystarch
    2014-12-17 21:07:23

    MSRP seems to be different on the ATI site at $4595.00 Did that change recently since the time of writing this article?

  • porscheguy
    2014-12-17 19:56:18

    Looks like a nice amp. I'll bet it sounds great.

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