ATI 1504 Multichannel Power Amplifier

      Date posted: April 11, 1997

ATI 1504 Power Amplifier
Sugg. Retail: $2450 (CAN)
Distributor: Artech Electronics Ltd.,
42 Lindsay Ave.,
Dorval, Que. H9P 2T8
(514) 631-6448 FAX 631-1212

(Reprinted from the Spring 97 AIG)

      ATI (Amplifier Technology Inc.) is a California company that is said to have been in the amplifier business for 30 years, perhaps like Canada’s Bryston in the U.S. until recently, a well kept secret for much of that period. The ATI principals, designer Morris Kessler and partner Mike Pontelle, both come from SAE, Pontelle a former partner at that company, too. Well, now they have distribution up here, with a very specific product line: amplifiers, all identical except for the number of channels. The 1502 is a stereo amp, while the 1504 reviewed here is 4 channels, and the biggie, the 1506, offers 6 channels to play with, to play bridge with, if you like; while the channel power module in each amplifier is identical at 150-watts/8-ohms and 225-watts/4-ohms, any pair can be bridged for 450 watts into 8 ohms.

      Pretty utilitarian in appearance, these amplifiers all bear a resemblance to a 4B NRB (the newer STs having a more attractive understated elegance) with their side-mounted heat sink arrays. They also use toroidal transformers inside, in this case one per channel pair. According to the product sheet, “Identical detachable modular components allow quick field replacement.” Sounds like this company’s been in the pro amplifier business for 30 years.

      For a couple of hundred dollars more, you can have your ATI turn on automatically via a low-voltage signal, which energizes a 50-amp relay that opens the AC flow and makes your meter go faster and your power company happier.

      Actually, these class A/B fully symmetrical circuit amplifiers are fairly easy on the AC, and run quite cool with good efficiency. On the rear panel gold-plated RCA input jacks are provided (no balanced inputs), with plastic-nut, gold-plated binding posts for speaker output, these closely clustered enough to discourage large spade lugs…yes we have bananas. The 1504 arranges these terminals in a straight line across the chassis bottom rear centre, making bananas the only safe connection method.

      On the front panel we find a cluster of LEDS to show proper operation of all channels, a signal one just below another that indicates clipping in each case. A large rocker power switch is to the left of these.

      I listened to the 1504 just after the Sphinx separates, continuing to use the Project Two Mk II preamplifier and Micromega Stage 6 CD player. This offered a good basis for evaluation, especially of dynamics and soundstaging, both important aspects of home theatre performance.

      The ATI stage was more contained than that of the mighty Sphinx monoblocks, less wide and layered front to back, but very stable and precise between and behind the speakers. The bass was very tight and solid, with a nice punchy quality that will serve well with soundtracks; this amp kicks a lot of butt in the bottom, as well as having the power to drive the Veritas to century dB levels. I could not make it clip and stay in the room, though less efficient, higher impedance speakers might. If so, then time for bridge!

      Though not as revealing as the remarkable Sphinx amplifiers, the 1504 offers a lot, including lots of channels, for its price. It is also an excellent candidate for vertical bi-amping, this able to further tighten and energize the bass while providing even greater midrange and top end power capability. I found this approach also seemed to reduce distortion at very high levels.

      How does the ATI compare with other home theatre and audiophile amplifiers? The closest to a direct comparison was with Bryston 3B ST and Sunfire Cinema Grand, both of which I listen to regularly. I would say that the sound of the 1504 is a little warmer and less focused in the bass than either, but perhaps a little more dynamic (though this one is pretty hard to pin down); the 3B ST is more revealing, while the Cinema Grand is more neutral. These differences are very slight, and though I think our references are better amps overall, they are also more expensive if you consider that we’re talking about 2 3Bs (in terms of channels) at well over $3000, while the Cinema Grand (with its 5 channels) approaches $4000 up here in the great white north.

      Perhaps a more appropriate comparison might bewith the Parasound multi-channel amps, which in my acoustic memory were a little warmer and more coloured than the ATI, but comparably priced. In general, the ATI range appear to be very good and well made amplifiers that will play clean and loud for a long time, and the 1504 is an excellent choice for a high end home theatre. A pair of 1504s could provide 450 watts x 3 in bridged mode, while still leaving 2 150-watt channels for the surrounds…sounds awesome to me.

Andrew Marshall

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