Power Amplifier Reviews

The hardest part of the setup was removing the reference amp from my actively cooled A/V cabinet that sits about 5 feet off the ground and is built into a side wall. I hooked up each of the ATI amps via custom-made Canare L-4E6S Star-Quad balanced cables with Neutrik NC3 connectors to a Marantz AV8802 preamp/processor. Other source components included an Oppo UDP-203 Ultra HD Blu-ray player, a Logitech Squeezebox Touch, and a TiVo Roamio DVR. One physical plus to the ATI amps is that they aren’t as deep as either Parasound amp I own, so it was much easier maneuvering them into my enclosed rack and making all of the connections.

Power Play
ATI recommends running the amps continuously with music for the first seven days to expedite the breakin period. Some argue there’s no science behind this, but I have to admit that the more I listened to the ATI amps, the better they sounded over the month I had them in my system. Did my ears adjust to the tonal quality, or did the amps actually improve? Hard to say, but these are outstanding amplifiers, regardless of the amount of hours put on them.

I customarily spend the vast majority of my audition time on multichannel movies. However, I was fortunate enough to be on vacation from my day job for the majority of this ATI review period, so I dedicated a lot more time to two-channel music listening than I usually do, tapping into the folder of FLAC files I keep on my home server. My familiarity with each track’s nuances allows me to quickly hear if anything is lost—or gained—when a new piece of gear is introduced to the chain.

“My Love Is” from Diana Krall’s Love Scenes is a great demo track, starting with finger snaps setting up a beat that’s soon accompanied by the bass. The simple jazz tune has a faint echo, giving the recording a very airy sound that can be lost with lesser amps, but the AT527NC conveyed it without any polluting of the sound—very clean and natural. When Krall’s sexy voice kicks in, the imaging is mesmerizing, and it gave the illusion that the center channel was active, even though I was listening in stereo; it was perfectly balanced, making my front wall come alive as if it were one giant speaker.

The same could be said of the amp’s performance on the title track from Janis Ian’s Grammy-nominated Breaking Silence. The FLAC file has a very analog vibe to it, even though it was sourced from a CD. I love using it to test dynamics and imaging. The song opens with a quiet solo-voice section that draws you in before the close-miked percussion and acoustic guitar enter. With highquality equipment, you can actually hear the fingers moving over the guitar strings, and that’s exactly what you get with the ATI: unabashed transparency. The amp doesn’t color the sound in any perceptible way, which is how I like it and how it should be.

Moving to multichannel music, I popped in the Blu-ray of the Eagles’ Farewell I Tour: Live from Melbourne, which boasts a powerful DTS-HD Master Audio 5.1 soundtrack that I upmixed using the Dolby Surround mode in my pre/pro to utilize all 11 speakers plus my two subwoofers. The 5.1 track is very engaging and features a robust midrange and some added punch in the LFE channel. The program includes 30 songs from over the years, and whether I listened to a soft ballad like “Peaceful Easy Feeling” or a harder-hitting number like “Life’s Been Good,” the ATI amps delivered a jaw-dropping experience. As with my two-channel test, vocals were clear and lifelike, imaging deep and wide—and frankly, the music sounded completely natural and uncolored. I felt like I was sitting in the crowd, which is the highest compliment I can pay.

Movie soundtracks were just as impressive, especially the Atmos versions on some of the latest Ultra HD Blu-rays, such as Sully and Suicide Squad. The latter movie is mediocre at best, but its Atmos mix is quite active and features plenty of pans and discrete overhead action. The ATI stack never broke a sweat, even with the challenging load presented by my M&Ks, and directional cues were placed perfectly in the room. Dialogue was clean and intelligible, and the soundstage definitely conveyed the best of what advanced audio brings to the table.

Sully, of course, is Clint Eastwood’s telling of the “Miracle on the Hudson.” Although some of the interactions between Captain Chesley “Sully” Sullenberger and the NTSB are fictionalized (as are other dramatic elements), the in-flight sequences mimic the actual flight recordings and are chilling—yet they’re inspiring at the same time, in light of how calm Sully was during the life-changing (and life-saving) event. This is an astounding video presentation on Ultra HD Blu-ray, and the Atmos track is just as phenomenal. As someone who flies 40 weeks a year for work, I can testify that the in-flight sounds are eerily lifelike when the perspective is inside the pressurized cabin. Exterior scenes are just as enveloping: Pans move throughout the room, taking great advantage of the overhead effects in a plethora of flybys. As with all my other demos, the ATI stack never missed a beat in conveying powerful dynamics and astounding imaging.

Conclusion
As you can probably tell, I really liked these ATI amps. They offer everything one would want: powerful dynamics and uncolored sound. Given their Class D architecture, they run extremely cool compared with my main reference Class A/B amp—which isn’t such a benefit in the cold of winter but will be a godsend come summer. And now I’m really looking forward to summer because I liked these amps so much, I actually bought them as an upgrade to replace my Parasound A 51, a well-established audiophile/videophile favorite that has been my reference for many years and through many other amplifier reviews. That’s quite an accomplishment for these ATI amps, but I feel confident in saying they deserve to be placed in the same high-end category—and they represent extraordinary value to boot. I can’t recommend them enough.