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ATI SIGNATURE SERIES 6005 OR CLASSE CT 5300??

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.
128x128jays_audio_lab

Showing 6 responses by clpetersen

clpetersen
7 posts
 
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.
clpetersen
7 posts
 
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.
clpetersen
7 posts
 
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!
clpetersen
7 posts
 
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.
clpetersen
7 posts
 
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.
clpetersen
7 posts
 
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.
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