This amp provides a lot of energy on Magnepan as wells as Martin Logan speakers. Middle range is particularly clean. Bottom end is sufficient and high is adequate. Sound stage is large but not better than Nakamichi PA-7's amplifier, which costs more on used market. I find that it is not much difference on bridged mode or 4 channel alone. Highly recommended.

I have owned an ATI 1502 for a year now. It is being used with my Vandersteens and it is fantastic, I love the sound, the peroformance and everything about it. Just read the review on the 1502 and was surprised cuss ive talked with other people and they are more than pleased with the performance of there unit. Oh well just goes to show, it's all in the opinion of the listener.

The ATI AT-1502 (2 channel), AT-1504 (4 channel) and AT-1506 (6 channel) areall the exact same amps except for more channels and more transformers
to meet the power demands. The 1504 at $1395 is an amp I would put against any amp costing three times that amount! It is a wonderful sounding amp just using it's four channels alone, conservatively rated at 150 watts per channel into
8 ohms, 225-300 watts into 4 ohms. But flip the switches on the back and move the speaker jacks over, and this 4 channel amp turns into a 2 channel audiophile
dream! 450 big watts per channel into 8 ohms! 800 to 1000 watts into 4 ohms!!
If you have an audio store in your area that handles ATI amps along with some of these more expensive amps ($3-6Gs), challenge them to hook them both up to the same speakers through a switch box. Nothing else needs to be said! Read the
review on the AT-1506.

I've owned the 1504 for about 2 years now and I can say without reservatiopn that is is the best amp available for anything in its price range (and well above). I am currently driving a pair of Duntech Crown Princes' with the ATI bridged. WOW! Somewhere in the park of 900 w/ch into 4 ohms! Anybody who finds this amp anything less than magnificent should have their hearing checked. I know the theory behind bridging is less than favorable for the audiphile crowd, but I'm telling you, the sound could not be more fluid and dynamic; nothing is compromised. I' ve auditioned everything from Bryston to Krell to Mark Levinson (all, by the way, are excellent products) and the ATI has impressed me enough to keep it and sell the others. No smoke and mirrors, no hocus pocus, just clean brute power in an affordable package. What more could anyone (well most of us) want. Highly recommended

The ATI 1504 is a high power(150w/chan) 4 channel transistor amp. I recently purchased one with the intention of biwire/biamping my Totem Model 1,s. This was a component match made in hell. The Totem,s revealed this amp for what it is. A hard sounding, sterile , totally non musical amp , best suited for undistinguished home theater setups. On the plus side , it does have huge current reserves, and battleship build quality, but if you value your two channel audiophile senses. Stay Away!

EVERYTHING!!!!!!!

NONE....

I had previously purchased an ATI 1506 amp to be the sole amp to power my home theater speakers, but I learned about the bridging option and had to bridge all 3 front speakers with that. So, I ended up buying an ATI 1504 4 channel amp so I could bridge my rear speakers too. All I can say is.....WOW!!!!!! I LOVE ATI!!!! What a great piece of equipment. The ATI 1502, 1504 and 1506 all have the capability to be bridged.... I love the possibilities all of these amps give the end user. The possibilities almost seem endless. The sound these amps produce is mind boggling. I have NEVER experienced anything so natural and dynamic as these amps. The amps seem to be the most prominent improvement to my overall system upgrades. When I went from an a/v receiver to seperates, the sound change was giant. I am one happy ATI owner and will never hesitate for a second to recommend this line of amps to anyone. I also want to say that Ed Frias from EFE Speakers is such a wonderful person with all his knowledge and direction. Ed showed me the ATI line of equipment and showed me and explained to me all the things I didn't know before.