While i've never heard the ART SLA-1, i read as much about it as i could find on the net. From what i can tell, it is pretty much the same thing as their DIO dac. That is, ten pounds of parts crammed into a two pound box.
In order to obtain the power output that they are and not run into thermal problems, the amp has to be biased quite low. There just isn't any heatsinking / chassis that would allow a higher level of bias. If it was biased higher, the amp would be going into thermal shutdown on a regular basis. As a general rule, low bias amps tend to sound a lot less refined, lack black backgrounds and do not offer the amount of "air" that a good high bias amp can offer.
On top of this, the power supply has to be compromised for the same reason i.e. small chassis size. There just isn't enough room to get a good sized transformer or filter caps in there. To prove / support this point of view, the amp is rated at 100 wpc @ 8 and only 130 wpc @ 4 ohms.
The logical deduction to all of this is that the amp would lack bass impact, definition and control. I would also expect it to get noticeably "smeary" as drive levels were increased, moreso as the impedance of the speaker were dropped. This all has to do with the lack of available current with limited power supply reserve.
While i know that i've not heard the amp and some of you are probably rolling your eyes / saying what a "dork" i am for jumping to conclusions, you just can't get around the basics of good amplifier design without some phenomenally fancy circuitry being required. Since phenomenally fancy circuitry typically requires a lot of R&D ( research & development ), the end result is typically a product that is quite costly to bring to market.
Given the price / size of this unit and the rated power output, it is probably nothing more than a cut-corner design that takes up minimal space. It was probably built to a price point ( i would assume VERY much so ) and to suite the non-demanding nature that one finds driving small monitors listened to in near-field fashion in a studio. In such a situation, volume levels are never real high and the amp doesn't have to control a large driver with a lot of reflected EMF being generated. As such, it probably works fine for the market that it was intended for ( after all, Studio Line Amp is the name ) but would not be suited for a true "high fidelity" system. Sean
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