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ATI AT1506 Six-Channel Amplifier Review

Home Theater Magazine
by Terry Landry

A modular approach to multi-channel amplification

It seems that as more manufacturers compete for the home theater consumer's buck, quality improves and prices drop. Capitalism's finest moment: better quality, more options, lower prices. And it should come as no surprise that some of the best values in home theater gear (amplifiers, especially) come from right here in the good ol' U. S. of A., including that den of iniquity we like to call home-sunny, funny Southern California. Enter Amplifier Technologies Inc. of Los Angeles, a company that, in one form or another, has been in the business of amplifier design for the past few decades.

With their newest line, the Series 1500, ATI's designers have proven they've got their fingers on the pulse of the market. We at HT continually whine (in the consumer's best interest, of course) about cost-cutting features like cheezy connectors, poor chassis quality, even poorly written owner's manuals. After checking out the series 1500, we were impressed with the attention to quality evident in every design feature of the series. These two-, four- and six-channel amplifiers (the $795 AT 1502, the $1,395 AT 1504 and the $1,995 AT 1506, respectively) arrive on the street ready to lay some bad hurt on the competition.

We tested the six-channel AT 1506, but the three models differ only in the number of channels--all internal components are identical. The first thing we noticed about the amp is its hefty size. The designers of the 1506, however, wasted no internal space: This beast weighs in at a hulking 88 pounds. This will keep the scrawnier members of society from moving the amp, but I'll bet that shelving it in the lowest space on your rack might keep the rack from toppling during an earthquake. Enormous heat sinks (more than 300 square inches of radiating surface for each channel) adorn the left and right faces of the beefy 13-gauge steel cabinet. The sinks are well-finished, too-no razor-sharp edges like you see on some cheaper brands.

ati at1506 audio power amplifier review home theater magazine

The simple front panel sports only the LED-lit power switch and six dual LED indicators for normal and peak power status. The rear panel is almost as streamlined: six gold-plated RCA input jacks, a DB-25 connector for easy one-cable hookup (if you've got a pre/pro with DB-25 output), an IEC power cord connector (so you can use a high-end power cable), plus six sets of gold-plated binding-post speaker outputs (these have safety collars around the base, so you can't use spade lugs with them). There are also switches to bridge operation between each set of dual channels.

The 1506 churns out 150 watts per channel and when you bridge this bad boy's channels together the resulting slug is a whopping 450 watts per bridged channel. By bridging all dual channels, I was able to send 450 watts each to the front mains and center channel in my system; I then hooked up an additional three-channel amp to power the rears and drive the woofers of my big NHT VT-2 speakers. Did it ever sound deep! For a Dolby Digital rig, try bridging all six channels of the 1506 to your front three channels as described above and then add a four channel 1504, bridging 450 watts to your rears. This will provide you with 450 watts in each of the five channels. Chances are you'll never go back into a cracker-box mall movie theater again, unless you enjoy having philistines behind you spilling drinks on your shoes and loudly discussing inanities throughout the entire feature.

The 1500 series employ ATI's Detachable Modular Component system, which is one of the nicest features we've ever seen designed into an amp. Each amp channel occupies a modular circuit board that can be easily swapped. ATI builds in fuse fault-indicator lights; you or your dealer can simply call up ATI, tell them which light's on and they'll know what's wrong. If there's a circuit board defect, they'll FedEx a new board to the dealer, so you're only out of service for a day or two. In the event you ever have to put the system to the test, ATI warrants the unit for seven full years, parts and labor.

Each pair of channels shares its own toroidal transformer (for a total of three transformers) and there's 18,000 microFarads of storage capacitance per channel. The excellent power supply raised our expectations: We've found that the more discrete each channel's power supply is, the better the sound usually is.

But does the AT 1506 sound good? You'd better believe it. We hear a lot of power plants pass through our lab's door, but this one kicks the competition's bottom. My current power array is a Denon stack consisting of the POA-8200 and POA-8300 (two and three-channel designs, respectively, at 120 watts per side), which have fared extremely well in the pages of HT, both in stand alone reviews and in blind Face Offs. The sound of these Denons is refined, elegant and warm- I wouldn't trade them in for anything, even preferring to pass on much more highly powered units because of my strong allegiance to the Denon sound.

With the 1506, the sound could be best described as having the same warm, clear and refined quality that characterizes my Denon stack, albeit on major steroids. During my evaluation, I checked out one of jazz saxophonist Joe Henderson's better recorded efforts, So Near, So Far (a tribute album to Miles Davis), because it marvelously captures the eerie use of space so characteristic of the music of Miles; it's an incredibly transparent recording. Likewise, The Call, a graceful and moving CD by Charles Lloyd, the tender warrior of jazz, can always be relied on to point out inadequacies in any sound system, because it marvelously captures the eerie use of space so characteristic of the music of Miles; it's an incredibly transparent recording.

Likewise, The Call, a graceful and moving CD by Charles Lloyd, the tender warrior of jazz, can also be called upon to point out the short comings of a sound system (and is a current fave among HT editors). Violinist Gideon Kremer's new release Hommage a Piazzola which uses Europe's finest chamber musicians to showcase fresh, rich arrangements of Argentina's most passionate composer, the late Astor Piazzola, also took a spin during my listening sessions. The 1506 handled the delicacies of these various recordings with the refined touch of a surgeon. And when I moved on into hardcore electric jazz/funk group Tribal Tech, the amp cooked up almost enough ions to blow the walls down.

The 1506 also displayed equal measures of sensitivity and strength when in surround mode. GoldenEye was downright frightening--just ask my darlin' Lufiine. No muddy-sounding dialogue, none of the shrieking that's often passed off as clarity, or as "meeting the demands of home theater." Just neutral, natural, clean power-massive amounts of it--from top to bottom. This is the way amplifiers should be designed. That said, I'll give the ATI 1506 an unqualified recommendation: This is the best amp I've heard all year.