Price Paid:  $1099.00 from onecall.com

Summary:
This is my first experience with an outboard amplifier. I had been using a Sony STR-DA777ES receiver (their last push/pull receiver design, 120 watts per channel) to power my NHT 2.5i, Audiocenter 2, and 1.5 speakers. The NHTs are well known to be demanding on amplifiers, and to me, the Sony receiver sounded great. By contrast, my Outlaw 1050 receiver sounded thin and sizzlingly bright on these speakers (and still does on my NHT super zeros). The ATI has the sweet sound of the Sony, but with a noticeable improvement in overall clarity (transparency?), bass depth and control, and, of course, power and dynamics. Where my Sony receiver would begin to clip, the ATI shows no outward sign of distress – I have yet to light up the “peak” indicator LEDs on the front of the unit, despite having tried (I was limited by concern for my neighbors, though). The ATI hardly even heats up, in fact, and is doing just fine inside my equipment rack with about 4 inches air space above, compared to the Sony receiver which heats up like a toaster oven and requires exterior mounting. My experience with hi-fi amplification (probably more mid-fi) has been limited to my NAD integrated and demonstrations in shops (the few times I get to go), and my headphone setup (Sennheiser HD 600s with Headroom Supreme amp). I therefore cannot offer comparisons with other brands of separate amplifiers. I can, however, say that I have heard bright and harsh amplification, especially with my NHT speakers, which are notoriously revealing, and the ATI is neither bright or harsh. I can also say that this amplifier sounds considerably better than the highly-rated NAD integrated, which I thought sounded rather thin and bland (even on easier speaker loads, like the 91 dB Acoustic Energy Aegis Ones). I can also say that my system now sounds closer to my reference headphone system than ever before, and definitely easier to listen to. I am very pleased with this amplifier’s sound. Add to that the weight (get help or you’ll seriously hurt your back), finish, and build, and this is one very fine amplifier for someone upgrading from a receiver, and a bargain at the reduced price. Associated equipment: Sony STR-DA777ES receiver (as preamp/surround processor) NHT 2.5i main speakers NHT 1.5 as surrounds NHT Audiocenter 2 Velodyne HGS-12 subwoofer MIT Terminator 2 speaker cables, interconnects Sony 222E

Strengths:
Power. Clarity. Smooth, non-fatiguing sound.

Weaknesses:
none for me.

Similar Products Used:
No other stand-alone amplifiers; but many receivers, NAD C350 integrated amplifier

Price Paid:  $1600.00 from Hong Kong

Summary:
Over 40 people in this review can''t be wrong. I vote for 5 stars too! Probaly has the highest $$/RATIO. 73 net lbs. of quality! Best medicine for Japanese AV receivers of any price! Poor man''s Bryston?

Strengths:
cool temp., power, sound quality, value

Weaknesses:
Front power light a little too bright

Similar Products Used:
NAD, Yamaha, Denon

Price Paid:  $770.00 from EBay

Summary:
I don't have the opportunity to "audition" many amplifiers where I live, so I had to rely on product reviews and a lot of digging for specifications to base my buying decision on. I noticed that the ATI amplifiers had much bigger transformers relative to rated power than the competition. Too, ATI has a transferable warranty, most others don't. Easy decision! It's just amazing to me how little these great amplifiers go for used on EBay! Just email ATI with the date, and location of origional purchase and you're covered! These things are so far ahead of recievers it's simply amazing. I'll run a dedicated circuit to this beast soon so my lights don't dim when I power this baby up! I am in awe of this outstanding product.

System notes:
DefTech BP-2002 mains, DefTech CLR-2500 center, KLH-2055 surrounds, 2 DefTec PF-15TL+ subwoofers. Yamaha HTR-5280 reciever used as a Pre-Pro.

Strengths:
Clean, limitless power, outstanding build quality, transferable warranty.

Weaknesses:
Not as well known as Parasound, or Rotel.

Similar Products Used:
Only recievers.

Price Paid:  $1200.00 from Reference-av

Summary:
I have had this ATI1505 for over 2 years now. It is being hooked to a Sony 9000ES pre amp and B&W's 604 speakers for front, 601 rears and CDM-CSE center. There is an additional Def-Tech 15Tl sub.
I originally purchased this amp 2 years ago but than moved out of the US and needed to amp to be onverted to 220V where my local electriciy was. No problem, ATI customer service suggest me to ship the amp to the company and this will be done at no extra cost for me. They stood behind their word and even ship the amp back to me at no extra charges. I have used the amp since then for about 2 years on the 220V system. Never had single problem with it.
There was another case I contacted ATI customer srvice and that was for to build some auto turn on for this amp, once again, I receivd all the help needed, cost be about $5 at rasio shack to get the parts and since then in the last 2 years this amp is on standby mode, and zerp problems.

As for the sound. I have searched a lot for an amp to match my speakers and the 9000ES and it seems to many folks out there have this combintion, so I went for that as well.
Within 6 month the system was fully broken in, I mean that, it was about 6 month... but then, the sound was simply incredible. This amp has power to reserve, it has huge soudstage and it somewhat neutral to trasparent sounding. It is not a warmth sounding. I like it that way. huge puch, i think this amp has the best mid range I have ever heard. The highs at high volumes might be a bit harsh but you will rarely get to that level, and I listen at high relative volumes. THe lower end is not its best part when comparing with the Parasound 2205 (that I currently have, and am not that happy with...). But the midrange if better than the parasound, so if you are using a high quality sub, and cross you speakers at aout 50-70Hz - I'd say the ATI is a no barainer.

For 2 channel mode, is has similar channel separation as the Parasound. Great 2 channel.
For HT use, I will simply not replace this amp for anything else.

The reason I currently have the HCA-2205AT is bcs my recent move back in the US, I was not able to bring the ATI with me as it is now 220V so decided to get new amp. the ATI2505 was not a question for me as I simpoly do not like this amp performance, a friend of mine has this amp together with DC-1 and Paradigm ref 100, and the sound is very weak. It is just too strong of an amp i the mid range part... So I decided between another ATI1505, or Parasound 2205 or the Rotel 1095. The parasound rated at 220x5 but, if the ATI1505 is only 150x5 than it is very conservative rating... they share about the same power.
I finally got the Parasound thinking to myself this is going to be an upgrade, well, it is a warmer amp, with better low end and worse mid range than that of the ATI1505, about the same power, highs are pretty much the same. For 2 channel I might enjoy more the Parasound. For HT use, the ATI is my pick!.
Not to mentioned the ergonomics of the ATI on the back compare with the Parasound which is very poor, no room for speaker cables at all.
All in all for the performance the ATI would get 4.5 starts from me, but for such great customer service and zero problems and pure enjoyment that I got from this amp, I simply rate this one 5 stars.

I still have my ATI and will sure continue to use it when am back home.

Highly recommended amplifier and company to work with!.

Strengths:
Punch. Quality. Power to reserve. trasparent sound. Soundstage. have I said quality. Build. Company customer service!.

Weaknesses:
Non!.

Similar Products Used:
Parasound HCA-2205AT, ATI2505.

Price Paid:  $1300.00 from ebay

Summary:
I have been using the ATI amp for a little over 2 years. I love this amp. I recently purchased an Anthem AVM20 preamp and a set of Tyler Acousic Tylo reference monitors. As I hooked up the Tylo reference monitors for the very first time (replacing a set of Mirage 3Msi speakers), I somehow blew out the electric fuse on the ATI amp (I'm not sure how, but the fuse did its job and protected the amp). Since I was dying to hear the new speakers, I connected them to a Halfer DH500 power amp (it was after closing time for Radio Shack, so I couldn't get a fuse until morning). I figured that I had made a mistake in purchasing the Tylo reference monitor speakers. I decided to connect it to a Kenwood KM-1 THX amp that I use in a different system. Again, I didn't like the speakers. I bought a fuse the next morning and connected the Tylo reference monitors to the ATI 1505 and WOW!! What a difference. I went from not liking the speakers to LOVING THEM. I have always been impressed by the ATI amp, however, it wasn't until I was forced to use the other amps (and the Hafler DH500 is a very decent amp) that I realized just how great this amp is for music. Of all the amps I've owned, only the Threshold 4000 was superior for music; and not by a long margin.

For the 2nd half of the story, when I couldn't get power to the amp, I did not initially realize that it was simply a fuse. There are fuses for the speakers and inputs, which were all fine. I didn't not realize that there was a separate fuse for the power supply. I immediately wrote an email to ATI and also left a message on their answering machine. I figured out the problem immediately the next morning on my own, however, I was very pleased to receive a phone call back from ATI that very day. There are so very few companies that will take the time out to call about a possible problem instead of sending an email. I am very impressed with the customer service. On all levels, I give this amp and company five stars.

Strengths:
smooth clean power, great for music and home theater

Weaknesses:
Yet to find one.

Similar Products Used:
Most of my comparisons were two channel amps including Bryston, Hafler, Kenwood KM-1 5 channel, Threshold 4000