involving sound that many listeners will probably fall for. But – and from the physical description above you can see that this amp has a big but – in my own view the single most important parameter of amplifier performance is smooth, flat frequency response with proper proportions of harmonic overtones. My experience is that one can listen to and enjoy a smooth sounding amp, even though it may be lacking in many other areas of performance. However, I have a difficult time with amps that sound harsh or bright in the upper midrange and lower treble, because while they are exciting at first, over time they can become irritating.
The ATI, from my perspective, is such an amp. The upper midrange sounds quite prominent, and the harmonic overtones emphasize the odd-order, harsh harmonics. It wasn’t the tilted-up extreme highs that bothered me, because they contributed to the detail and imaging. It was the all-important midrange that was excessive, where the vocals and primary instrument sounds occur. You should be aware that my favored sound comes from tube amplifiers, especially single-ended triodes, which to me have the most natural, musical, and enjoyable harmonic structure, though of course they are weak in certain other areas where an amp life the ATI excels. Much (but not all) solid state equipment sounds bright and harsh to me by comparison to tubes, and the question is a matter of degree. With the ATI, it’s the third degree. The lower midrange and upper bass sound truncated and recessed by comparison with the upper mids, meaning that singers and instruments lose their harmonic foundation. Edgy recordings get even edgier. Since many, many movie soundtracks are already on the bright side, a bright amplifier such as the ATI would, unfortunately, emphasize this aspect. Even a relatively smooth and well recorded soundtrack, such as the Dolby Digital track from Amadeus, ends up sounding somewhat thin. Fat amp, thin sound; go figure.
Some listeners will find this bright, detailed sound exciting and involving, and never tire of it. They will love the ATI, and enjoy all the other good qualities of the amp. Others will find that this brightness wears pretty quickly and will want to stuff their ears with cotton – or move on to more verdant amplifier pastures. This is definitely an amp that you should try in your own system, because you will probably find that you either love it or hate it. For me, it has lots of power but not enough finesse. It’s like being in heaven and hell simultaneously; I gotta’ love the good qualities but the one weakness seems to overwhelm them. For people who can live with its brightness, however, it represents excellent value for the money.