The ATI AT3005 arrived yesterday. It was supposed to be an AT3004, but ATI ran out of 3004 rear panels, so they gave me a deal I couldn't refuse on a 3005.
The 3005 does weigh about 110 lbs, but it is truly efficient compared to the Mark Levinson 334s it's replacing. The AT3005 = 5x300wpc @ 8ohms = 1500/110 = 13.6 watts/lb. The pair of 334s are 4x125wpc @ 8 ohms and together weigh about 220 lbs, so that's 500/220 = 2.27 watts/lb. It's a little better into 4 ohms, because the 334 is a more linear voltage source than the AT300x amps are, but the 334 still only achieves about 4.5 watts/lb. Yeah, I know some pro amps like Crowns do a lot better in watts/lb, but they aren't Class AB audiophile things, so there.
The build quality of the AT3005 is very good, about equal to the Levinson, I'd estimate. The 334 is more expensive due to massive over-engineering (like a separate 800 VA transformer per channel; the 3005's five channels share two transformers) and more expensive cosmetics. The heat sinks on a 334 are a work of metal art, on the 3005 they're internal. The 334 uses solid copper buss bars for power distribution, soda-can sized power supply caps, and when you take the lid off everything is so pretty inside you want to leave the lid off, just for show. The 334 also uses predictive bias level control, which has benefits of unknown value, but it sounds cool! The 3005 is utilitarian and is a more simple design by comparison.
Architecture-wise, both the 3005 and the 334 use fully balanced circuits, meaning they use two mirrored amplification signal paths per channel in differential mode. This is pretty much the state of the art, so you would think that both well-designed amplifiers would perform alike, but you'd be wrong. They don't. On the Salon 2s both 334s generate an audible hiss through the tweeters at idle, and they have since day 1. And, no, nothing is out of spec. The two 334s are so precisely built with matched components that their sensitivity is identical enough that I can vertically bi-amp each Salon 2 with a 334, and a point-source sound (like a human voice) is perfectly centered between the speakers. And that was true even with my old 95db/2.83v Legacy Focus speakers. Now that's precise unit-to-unit matching.
The 3005, on the other hand, is dead quiet through the Salon 2s at idle. That means the low output SNR must be *at least* 5db lower than on the 334, and probably more like 10db lower. I wish I had the equipment to measure the difference.
Can I hear the difference in sound quality? I don't know yet, but I doubt I'll be able to. Nonetheless, not having that hiss makes me happier, and that's worth something. Not priceless, but worth something.
The cool thing is that the 3005 cost less than the resale value of just one 334. Now maybe I can have that DEQX pre-amp unit GranteedEV turned me on to, once I sell the 334s.
