Good afternoon all,
i am currently in the market for a 5 channel power amplifier. i just recently sold my classe audio ca 5200 and i truthfully LOVED IT. It has been THE BEST multichannel power amplifier i have owned PERIOD. I loved the smoothness and soundstage. i felt it had a taste of 'tube like sound' if you will. That being said, my plan was simply to move up to the ct 5300 which has more power and some say it has better bass control than the ca5200 which was one of the things it was criticized for. however, i started to read reviews on the new ATI SIGNATURE 6005 and its amazing noise floor etc and of course every magazine is raving about it. Having owned outlaw audio amplifiers before which are built by ATI as well, i am wondering if the signature series is just a little better than the regular at series ? they seem to be a little on the forward side, but i have spoken to several dealers who claim the signature series is neutral, not forward and that it is a spectacular upgrade over their regular series. However, i don't really see anyone else who has given it their own review and comparing against their former amplifier. yes, there is a reviewer who said it was just as good if not better than his parasound a51.
My current set up is martin logan montis, motif x, and i will eventually get the martin logan EFX surrounds. AS far as a processor, i am only using the ps audio dac as a preamplifier because i am waiting on the marantz 8802 to release in february. i would say i am about 60% music, 40% movies.
Given my situation, what would you guys get? i would love to know anyone's input.
ATI makes excellent amplifiers. Well designed and well built in a no-frills chassis. If you go to their website there is a nice power point slide show on their factory in soutern CA.
Have the 2002 model (2 channel, 300 wpc @ 4 ohm, balanced). Also have Naim amplifiers and have had Copland hybrid integrated. I think the ATI does as well as the Naim at low listening levels and in this case (being more powerful) has much better punch for large dynamic range pieces (e.g symphonies). Better than the Copland in all respects. I sense ATI specs are fairly reported and are very impressive. Does what it is supposed to do, no more, and runs very cool as well. Case is well built and has a nice design, but no 12mm thick machined faceplates.

Subjectively, I find the sound stage to very stable which to me indicates a very good phase linearity across the audio spectrum, as evidenced by the specs as well.
i do like your feedback. However, i had the classe ca 5200 and i was floored when i heard its smoothness and soundstage. I still feel it is by far the BEST multichannel power amplifier i have owned. I am just VERY afraid of ordering the ATI and i don't feel as impressed as i was when i first heard the Classe. Something else that makes me afraid of the ATi 6005 signature is that it DOES NOT do 600 watts into 4 ohms. It only does 450 ohms and when i called them to question them why the power doesn't double, their answer was that it would mean that the amp would have to be MUCH LARGER and that it would need more capacitor, etc, etc. I feel like that was not a really good answer. I mean, it has been well known that an amplifier which DOES NOT double its power when presented with 4 ohms, it is simply NOT as efficient as one who does. I mean, the amplifier is already LARGE so why not go all out and make it double its power? Anthem does this with the p5, Classe audio does this with their CT5300 and CA5300, so why couldn't ATI do it when they are supposed to be amazing when it comes to power amplifiers? i mean, this is THEIR expertise.
I have the funds in hand to do this, but something isn't feeling right about the ATI. I can't pin point it. I feel as it is just another ATi with a different face plate.
Classe makes a very good amplifier, no doubt. But i do think you may be looking at specs soemwhat misleadingly (and manufacturers often help this along). Not saying Classe does this, I doubt it. But:

1. Doubling down. Yes this is indicative of a good power supply backing up the amplifier section. However, amp manufactures are known to downplay their 8 ohm power to get doubling down on their specs. For example, one rrecently tested (wish I could remember the post) amp rated 8 ohms at 200 but actually delivered over 300. However the specs said: 200/400 for 8/4 ohms to look better. The 400 was accurate and the 200 was also accurate but deliberately understated.

2. 600 vs 450 - not terribly important. Only about 1.2 db louder- barely noticeable. Look more at slew rate - how fast can the amp respond to a rapid change in signal and create the dynamic punch? if the amp can get to 600W, but takes a 1/2 second to get there, so what? (exaggerating)

You would not be unhappy with Classe at all. But I don't think the reasons you cited are the right ones. Buy what you like and have fun!
I agree with what Clpetersen.

ATI makes some of the best SS amps out there. The slew rate is fast/ sq wave input is nearly perfect. It is an incredibly fast amp. I don't think ATI makes most of their money from selling ATI amps, but instead is a supplier of amps for many big name companies. They are well known in the industry as a go to place for amps.

450W on a 91dB rated speaker (montis rating) is a ton of power. I'm not sure of the size of your room, but I know I wouldn't want to be near it at anywhere near is at full volume. The bass module in those speakers only has a 200W amp and the bass requires more energy to produce to same SPL, so I wouldn't worry about the power rating of the ATI.
Also, if you even consider putting out 600W/ch into just a few of your speakers you will easily blow a 20A circuit. That is really a TON of power.

I've owned both classe and ATI amps. Both are great amps. Both are very neutral and you really couldn't go wrong with either of them. The ATI is made in the US, the Classe in China.

I don't think your concern of bass is accurate because your mains have a built in woofer which means the amp won't be getting much draw for anything below 340Hz.
Both are fine amplifiers, I have not compared them. My questions is... With such a love affair with the Classe, why go elsewhere? Unless you can borrow something or get one on loan, why kick yourself later? You have pre sold yourself on the Classe.
I understand I should have just stayed with classe if I had already liked the ca 5200 but I was in a position to grab a great deal on a ct5300 where I almost had to put nothing out of pocket to make a lateral move into the more expensive 5300. I even read somewhere that this ct5300 is much better than the 5200 series. However, I just kept hearing recommendations and all the reviews regarding the ati signature. I have never heard their former classic series and I don't really like forward sounding amplifiers Because ear fatigue easily. I did hear the signature series is neutral and that this design shares absolutely nothing in common with their older design. It's supposed to be much faster of an amp. I do like to have 2 channel stereo listening sessions at times and the classe really impressed me In that area. Ati always gave me the feeling of just being a home theater amplifier, but again this signature series is supposed to excel at both. There are few people out there with this new ati amplifier which also makes me wonder why ? Anyhow, I have decided to be one of the very first ones with hands on experience and purchased a 6005 signature series. It will arrive soon and I will be finally able to see for myself what this unit is all about....
Your new amp is the same as the Lexicon ZX-7. I'm not sure which sold more, but they are out there.

Please let us know your thoughts.
i plan on doing just that. I have a pass labs XA30.8 that i am using for my 2 channel for now. It will be nice to see if it is indeed true that the ATI is very quiet and that this particular unit uncovers things you have never heard before in your music. I might still go ahead and buy the CT5300 and do a true A/B comparison.
I'm not sure this amp is the same as the lexicon zx7. That one is made by crown which is Harman which is entirely different from ati. How did you come up with that ? I owned the rx7 before and liked it.

Look at it the amps. Lexicon amp ATI amp

Don't they look identical except for color? Both have the same specs too. Shocking isn't it.

I'm not sure about the RX-7, but I'm pretty sure it was the previous Lexicon amps that were made by Crown, but not identical designs to any Crown, it was just their manufacturing plant.
I don't much abut the Lexicon, but the ATI signature and McIntosh MC452 (and 152) have some basic commonalities (excluding of course the autoformers). The most important being fully balanced designs using 'ThermalTrack' output devices which have on-board temp sensing. This allows real-time active biasing of the output stages, touted by both manufacturers.
If I were to ever move away from ATI, it might be to the MC452. Not expecting a huge improvement in sound, and would have to listen to see if the autoformer makes any difference that I can discern or like/dislike. But a Mac is a Mac. Paying some big bucks to get cool meters though. All fun.

Excepting certain things like autoformers and some of the deliberate harmonics of a Nelson pass design (using transformers), I think well designed SS amps have reached a high level of maturity. Most now have power bandwidths extending to over 80 kHz, and THD's below 0.05%. Things that I would like for would be excellent performance at low listening levels (think 'First Watt' )- like a class A or high bias (basically same thing as class A) design up to say 5 or 10 watts, etc. ATI does specs their amps at 1 watts and full rated power.
i have owned the lexicon rx7 and it is a VERY LAID BACK amplifier. It is so laid back that it almost makes it a must to buy a forward sounding preamplifier. That being said, the ATI, according to the reviews and my conversation with them, is SUPPOSED to be a NEUTRAL amplifier. They swear that this amplifier has technology and components that have NEVER been used. Again, the only way to tell is by actually listening to the units. If it is a rebadged zx7, rest assured i will be beyond disapointed. My thinking is that it is NOT a lexicon zx7 because this amp has been out since 2011-2012 i believe and the signature series supposedly has new technology in it and i seriously doubt it has EVERYTHING that zx7 has. It would shock me, but who knows what will happen. I go through amplifiers the same way i go through bottles of water. I don't think i have ever owned an amplifier longer than a year which is an advantage because i can certainly distinguish amongst them.

As clpetersen stated,
I think well designed SS amps have reached a high level of maturity
Most good SS amps are more alike than different. I can almost promise you that ZX7 and ATI are identical, I think they even came out the same year. I don't think that is anything to worry about. I know of only a few amps able to put out this level of clean power. The first that comes to mind is the Boulder mono that requires a 240V line. This amp requires 2 separate 120V lines because the power supplies are so goof that they can pull that much power.
Easily one of the most important parts of any amp is the PS unit because if you don't have good clean power there it doesn't matter what is after that.

If you don't like the ATI, contact me because I'll buy it from you. I guarantee it can go up against mono or stereo amps at multiples its cost.
Interesting (Sevan's post re: Lexicon Zx-7 vs. ATI 6005). ATI and Harmon International (owner of Lexicon) are both Southern California companies. ATI makes a large number of amps to be re-badged and Harmon makes a stunning number of re-badged products, or more accurately, a stunning number of similar designs under one roof. I took a private tour of their facilities a few years ago for business reasons not related to audio.
FYI GUYS, i just heard from a very trustworthy source who has a lot of experience with amplifiers that the ATI SIGNATURE SERIES is a Mark Levinson Unit... They are using ALL THE TECHNOLOGY they put in the mark levinson amplifiers and with a few more tweaks to improve it some more. I also heard from an actual owner that this amplifier made him sell the Krell Amp he owned (forget which model). So far, there are a lot of good indicators that this amp is nothing more than a Mark Levinson Unit but at a much cheaper price with better warranty..... :)

Your source may be mistaken. There is no 7 channel ML amp. The 7 channel amp from Harman is the Lexicon amp. It is probably true that most ML amps are also made by ATI, but this is not one of them. I assume they all use the same technology.
The five channel mark levinson is the same thing as the 6005 signature series and not their 3005 series. Next week I will let everyone know how good or bad this amp is. I also got feedback stating they the ati 6005 destroyed the parasound halo a51. It killed it in power and detail plus soundstage. It wasn't even close according to my source.
I am fairly certain the ATI will not disappoint. It is certain that the ATI is designed and built by ATI in their factory. Not clear where the Lexicon is made, though that is not critical.

I agree on soundstage; the 3002 which I have does an excellent job. I think this due to the power reserves and the flatness of the amplifier phase across the audio spectrum. I think these two attributes help 'lock-down' the soundstage - for example as a piano goes through its range (amplitude and frequency) a flat phase response will help keep it localized rather than start to float around. My opinion.

Not too many manufacturers I have looked at publish their phase response - I have seen ATI, McIntosh and Hypex NCore publish theirs; I am sure others do.
i am definitely looking forward to this amp. i will do a lot of 2 channel listening as well and since i own the pass labs xa30.8, i will be able to compare and see just how good or bad this 5 channel amp is. I will be using a ps audio DAC as a preamplifier for my 2 channel listening session and then i will be able to choose a processor based on how neutral, bright, or warm sounding i find the 6005.
Ok guys,
I finally have had the opportunity to connect the ATI 6005 signature series and spent a few days with it. Before i give MY PERSONAL opinion, let me discuss what other amplifiers i have owned:

and a few other amps that i am sure i can't remember right now.
I had a full 5.1 set up but downgraded to a 2 channel set up. What i currently own is the martin logan montis, PS AUDIO MK2 DAC and a macbook pro which is connected via usb to the ps audio mk2 dac. For my listening experience i used spotify and also tested a few bluray players in 2 channel mode via the oppo 103d connected via coaxial to the DAC.

With that said, i have done about 5 days of listening with all sorts of music and also a few movies. I typically use the same music that i have used in the rest of the amplifiers that i have owned so i am pretty well aware of what changes the music suffers as i try different amplifiers.
I will say the ATI signature series is a VERY WELL BUILT unit. Nothing and i mean NOTHING was forgotten on this unit and one interesting thing i noticed is that it ran relatively cool even at ear splitting volume levels.
Now, for comparison purposes, i used the pass labs xo30.8 and the classe audio 5200. Here is what i found:


1. The amp is very neutral. It seems as if EVERYTHING is "flat". The bass is strong, but NOT BOOMY or exaggerated. As you crank it up, it keeps hammering WITHOUT starting to take over. It really sounds tight without being over emphasized.
2. The high frequencies are on point and really crisp, but NOT LAID back or forward.
3. The midrange is really articulate and has enough "body" to let you hear what is being said.
4. When cranked up at over 100 db, i found it very VERY powerful and with a nice soundstage. You don't feel as if you want more of anything. It feels like it is just right. Nothing really jumps at you.
5. Lastly, the amplifier does give you the feeling that you are hearing what you're feeding it. It doesn't color the sound so IT WILL NOT forgive you if you through a crappy signal or source. It will let you hear it. You WILL hear things in your music that you didn't know were there before. I heard ambulances in the background of some songs i had no remote idea were there.


1. Because i was comparing to the pass labs and classe, i did find the ATI more "forward" and perhaps LESS tolerable at loud volume levels.
2. If you are "all about that bass" then i will say this amp might not be as "forward" in the bass department as perhaps the pass labs xa30.8. The pass labs actually had more low end oomph at low to moderate levels than the ATI.
3. If you are the type that likes to listen to your music at a low volume setting and expect to hear all the fine details of your source while not losing some low end frequency, this amp Will disappoint you. I listened to several songs and found the pass labs just MUCH MORE detailed at low volume levels. It feels as if the ati demands that you crank it up in order to hear what it can do.
4. If you crank the classe 5200 or the ATI as loud as you can handle it, the ati will give you a much tighter bass response BUT the high frequencies are sharper which in turn might make you want to turn the volume down. This is NOT the case with the classe. I can crank it up and i can tolerate the music relatively loud without cringing because the high frequencies are rolled up somewhat.
5. If you like a sweet sounding, warm music, this is not the amplifier for you. What does this mean? well, if you like pass labs, mcintosh, or classe then this amp might not be your cup of tea.

Overall, i do feel the amp is a big bang for the money. It doesn't really take away anything from you ,but rather give you more detail that you didn't know was there before. however, MY TASTE remains with classe audio for a multichannel amplifier and pass labs for a 2 channel set up. i have owned over 30 amplifiers in the past 12 months and NOTHING has impressed me more than the classe or the pass labs. Keep in mind, that i am a fan of music that sounds pleasant if i decide to blast it from time to time and typically warm or sweet sounding amplifiers are the ones that tend to reward with these qualities. I get ear fatigue quite easily and i have yet to find a better, or more comfortable amplifier to listen to at BOTH, low or high volume levels than the pass labs or classe audio.
In conclusion, after finalizing my review, i placed an order for the Classe CT 5300 power amplifier (i sold the ca 5200) and have decided that the ATI 6005 will need a new home. If you are interested in it, i can give you a very good deal so let me know :)
I would consider using something like Dirac live to give you more rolled off highs and increased bass at low levels. You really are not stuck with the designer's voicing anymore. You can also EQ with programs like Jriver.

Some years ago when I auditioned the Classe M-400 monoblocks, they sounded a bit rolled off. The newer Classa M-600 does not. I would check to see if the voicing of the newer CT 5300 has changed before I bought it. Classe makes great stuff, in China, hehehehe. Just kidding. Thanks for the excellent insights! I've stuck with Mcintosh so it's likely I might share the same preferences as yourself.
Hi guys,
so i placed an order for the classe CT5300 last week and i should have it this week. The week before that, i had purchase 2 mark levinson units from another audiophile friend (532h and 533h).
Let me just say that i had read bad opinions on the new mark levinson amps. Some say that it didn't sound as good as their older units ( never heard them) so i was under the impression that maybe i can just buy them and if i don't like them, i can at least sell them and use the CT5300 Classe that's coming this week. however, for THOSE OF YOU, who have doubted the new mark levinson amps, you will be VERY SURPRISED. I have been doing a lot of listening today and i STILL CAN NOT believe the level of detail and refinement these amps have. i am simply WOWED with these. They have layer of detail upon layer of detail. I can crank it up and not get ANY EAR FATIGUE of any kind. I find it very smooth, controlled and sweet sounding, but without rolling back the high frequencies which is what most warm sounding amps do.
I DONT CARE what people say that mark levinson is/was built by ati or crown or any other brand. i have owned dozens of amplifiers in the past 12 months and NO OTHER AMPLIFIER has had the level of detail and big soundstage that these levinsons have. Hell, i am willing to say that the 532h edges out the pass labs xa30.8 i had. YES, it is THAT AMAZING. I am really blown away in all senses. The more i crank it up, the more i hear details that weren't there before.
Yes, the 532h is a BETTER amplifier than the ati 6005 signature. It reveals more and makes you feel as if a curtain was opened. Music just flows towards you in a much more direct way. Those of you who think the signature ati is a mark levinson won't like me saying this, but the truth is that it is NOT a mark levinson when it comes to sound quality. it is in my opinion about 85% in terms of sound quality of what the mark levinson is. i am not a firm believer that this entire talk about signal to noise ratio levels, great specs, etc all mean NOTHING. What really matters is once you sit down in front of the speakers and let the music begin. Only then is when you can truly asses an amplifier's true soul.
For now, i regret having purchased the classe audio CT5300 because i wasn't supposed to be overly impressed by the mark levinson 532h but the truth is that i am beyond impressed with it. It is THE BEST solid state amplifier i have hear with my set up. It trumps anything else i have owned when it comes to refinement and detail. I think i have FINALLY found the amplifier flavor that i have been looking for. i now have to probably sell the ct5300 classe audio and begin looking for a good processor for these levinsons (i am thinking of the marantz 8802 once it releases).
Hello Whitecamaross -
thanks for the excellent observations on the Mark Levinson and ATI amps.

Since the first part of this thread dealt with the strong liklihood that they are the same amp, and your listening experience says very much otherwise, I am curious what they look like inside?

Are you comfortable taking off the cover? Just curious if Mark Levinson has done something to voice the amplifier differently.
i wouldn't want to take the cover off the amplifier. I am not sure WHAT they have done inside, but as i have stated earlier (and also confirmed by the buyer of my 6005 ATI), the ati is forward sounding when compared to the classe, mcintosh, pass labs or mark levinson. If you like clear, crisp and slight brightness, you will love the ATI. HOWEVER, this amp likes to be cranked up in order to fully enjoy it. It doesn't really shine when you are listening at low volumes like the mark levison and pass labs do.
I can now finally tell everyone out there that the mark levinson h series ROCKS and excels both, in high and low volume levels. It sounds SPECTACULAR and has unsat all the 30 something amplifiers i have owned. I don't have to even debate this. It is a clear improvement over anything else i have heard. Although ATI might be still producing mark levinson or not, they did SOMETHING inside that is different and strictly exclusive to levinsons and this specific tweak is perhaps something that the ATI simply CAN NOT do to their own amplifiers or else there might be some sort of a lawsuit involved and a lot at stake. It is no different than saying Chevy builds the Corvette z06 and the Camaro and although the Camaro has the same engine as the Corvette, the vette has milled heads, a different cam, better exhaust manifolds,etc,etc because it is targeted to exclusive buyers who are willing to pay more. They couldn't do the same EXACT engine in the camaro as they do in the z06.
Could ATI make the same levinson amp and badge it their own? absolutely. They have the formula to make levinson amplifiers happen, BUT they can't risk that. I am sure if they came out with an amp that is IDENTICAL to the mark levinson sound, they would get a call from Mark levinson immediately and things won't be pretty.
Martin logan and mark levinson are a match made in heaven. Nothing has sounded better through my montis.
Awesome Review!!! PM me the price you want for ATI 6005. By the way what speakers were you using in your listenings?