audio research REF 150

Just spent a couple full days using a demo 150 with my Martin Logan CLX full range electrostatics. Even though the MLs have a tough impedance that drops to an ohm at high frequencies, the best sounding tap by a large margin was the 16 ohm connection. The sound was very good and reasonably smooth.

Using a computer based RTA, i noticed that the response tilted downward as I moved the taps to the lower connections and sounded progressively better on the highest tap value. (not so good on the lower values)

Very rich and dynamic sounding. The fans are quiet but are audible when anywhere near the amplifier. The dynamics were very good and the amp was quiet even compared to a rock solid Class A Accuphase.

You can turn the fans down. There is a 4 way fan speed switch inside. Factory setting is maximum speed, but if you do not plan to put your amp in a cabinet of some kind, you can safely turn it down to minimum speed, or disconnect it altogether (that is how I used to run my Ref110).

Comparing the Ref110 vs Ref150, the new amp has double the energy starage (24x 470uf/450v caps in Ref150 vs 12 x 470uf/450v caps in Ref110), different coupling caps (may be the same as those used in Ref 40 - but not sure) and KT120 tubes.

I haven't had a chance to hear the Ref110 vs Ref150 side by side, since my Ref110 is long gone, but I think that the Ref150 has better bass (although still not state of the art in solid state terms), more clarity and resolution on top. It is increadibly dynamic, and retains one tf the Ref110 halmarks - excellent PRaT and midrange texture.

Overall, I still prefered my Dart, but the sound quality difference was nowhere near as big as the price difference may sugggest ($30.000 vs $12.000). If I hadn't had the dart, I might have bought the Ref 150.

Has anyone compared the REF150 to REF250?

In my brother's set-up driving the Sasha with full ARC (CD8, REF5), the REF150 sounded great. Buying the whole system at one go during the 110>150 transitional period, the local importer agreed to first lent him a demo REF110 (6550), and subsequently replaced it with the later KT120s equipped unit while awaiting arrival of his then to be released REF150--hence the observation in my first post above.

Curious as to whether the REF250--despite similarities--is significantly better, or close enough a call with just power difference. There were 3 sets recently at the dealer but were pre-ordered units and were sent off immediately to their respective owners so no chance as yet to audition one.

Also, if any experience on how these new generation ARCs compare to the like of LAMMs, VTLs and VACs--impressions preferably from owners or first hand experience in home/store demos. Thanks.

Can you display your graphics on clxs with ref150? We tried the clxs in 16ohm taps and works excellent !!!
But this will make less power from the 150

I would appreciate kick starting this OP again. Looking for more current comments. Just upgraded my Ref 5 to the SE. Initial impressions are quite positive, but the upgrade still needs more time to complete break-in. That's why I'm asking about the Ref 150. Wondering how much improvement I'll realize going from the VS-115 to the Ref 150. Kinda thinking that the law of diminishing returns will be kicking in.