Audio Research Amp Shootout

Over Labor Day weekend a few friends gathered to do something we have discussed for quite some time—do a comparison of several Audio Research amplifiers. This was partly inspired by prior upgrades where two of the amps were compared and partly by rivalry (tube vs. solid state, switching vs. analogue, older vs. newer, etc.) Ultimately, we compared the 150.2 (Tripath switching amp), 100.2 (solid state 100wpc), SD135 (solid state 130wpc) and VS110 (110wpc tube). Since we wanted to have some fun with it we didn’t adhere to a rigid formula, we simply picked out specific tracks from 5 CD’s of various genres (rock, jazz, classical) and then rotated the amps into the system, comparing one against another until we all felt that we got a good sense of each amps unique properties. At the end of the day we were, surprisingly, pretty much in agreement on how each amp sounded and, to a lesser degree, how we would rank the amps in terms of preference. What follows is my own assessment of each of these products and, where necessary, observations of others who did not share my perspective. BTW, I have at some point owned all three of these solid-state amps but never a tube amp from ARC or anyone else.

I guess the first thing to point out is that, to a large degree, ARC has managed to craft a “house sound” that is pretty consistent among it’s varying designs. There were not enormous differences between these amps. I suspect that rotating in an amp from Krell or a low power tube amp would have produced a much greater contrast. The other thing worth mentioning, perhaps, is the associated equipment and room, which can be seen on my system profile if you care to look. Since the amp-speaker interface is crucial in determining how each amp will perform, it is probably worth noting that the Daedalus DA-1.1’s are 97db efficient with a fairly stable impedance of 6ohms. With this said, on to the comparison….

We all generally concurred that the 150.2, while a very capable and practical, was not up to the sonic standards of any of the other amps. The bass was somewhat rounded by comparison (only the VS110 was similar in this regard, though more tuneful and lifelike than the 150.2) and, more importantly, the sound was less three dimensional and organic. In addition, the midrange had a slight hardness or glare, particularly when pressed, that made this amp less natural sounding than the others and least like what you would expect from ARC through this frequency range. I owned the 150.2 for quite a while (it replaced a 100.2) and liked the amp when paired with my Harbeth Compact 7’s. But with a larger and more revealing speaker, I don’t feel this is the best choice in the ARC lineup. It does run very cool and uses almost no power so I would give it great marks for being “green” and it will probably last a lifetime as well.

Most of us were eager to hear the venerable 100.2 against the new SD135. Here the comparison was much closer, with the SD135 offering slightly better inner detail, warmth, refinement and slam. The 100.2 was a little more brightly lit on top, with greater sparkle to the highs. The SD135 is ever so slightly darker hued than the 100.2. For wine lovers an apt comparison would be the 100.2 representing a good, young California cabernet while the SD135 and excellent French Bordeaux. The 100.2 was a little less sophisticated and brash, the SD135 more subtle and nuanced. All but one of us preferred the SD135, some by a large margin, myself less so. The SD135 is also a bit more user friendly and appears better built. The on-off switch is more substantial and the on sequence reliably comforting. It is also more substantially constructed under the hood. Overall, both of these are very fine solid state performers and it became clear through this comparison that the 100.2 deserves much of it’s cult like status among ARC amplifiers. But the SD135 was, for all but one of us (the owner dare I say?) the better product overall. It sounded more realistic, dynamic, dimensional and authoritative and was sounded better than the other amps in the shootout on all types of music.

Equally intriguing was the comparison of the tubed VS110 with the other solid state amps. The VS110 possessed greater dimensionality and was more engaging through the midband—realistic textures and more subtle inflections and variations of voice and instruments could be heard. But it did not have the speed, dynamics or ability to project sound as well as either the 100.2 or SD135. The VS110 was a joy to listen to—it spent more time in the system at the end of the day—and captured a bit more of the emotional content of each recording, though the SD135 was very close in this regard.

Again, these are mostly my impressions based on my room and system. Your mileage may of course vary. But it was a really interesting exercise that I thought may be of some benefit to those looking at any of these amps for their system. I know this posting is short on details—I’ve been trying to find time to finish this write-up for weeks—so if you have any questions please feel free to post them and I’ll try to respond to specific areas of interest. Happy listening!