Tube amp advice


I am thinking of trying out tube amps. My current amps are Kharmas (MP150). My speakers are Wilson Benesch and they are not an easy load (sensitivity is 86 db, impedence 6 ohms).

So, it would seem I will need a pretty perky tube amp. Some research has shown me that the EAR 890 and the Rogue M-150's are good values in my general price range, are well regarded, and are powerful enough to drive my speakers effectively.

Any thoughts on how these two amps compare? Any thoughts on other amps that might work well?

Thanks in advance.

--dan
dgaylin
Deltatrippers:

I intended to make a comment in response to your post, but forgot. I ran the original Revel Salons for three years and at least with respect to the original Salon, believe that the standard advice about powering the speaker at the time, which was that it sounded best with massive amplification, was dead wrong. The first and current versions of the Salons both use high-order crossovers and proprietary drivers that can handle a lot of power - one of my dealers had a customer that ran a pair of the original Salons with 1,200 watt monoblocks and they indeed can go extremely loud, cleanly. But this misses a crucial point, which is that the Salons are also very much a finesse speaker that comes a lot closer than many state-of-the-art speakers do at accurately reproducing the sound of unamplified acoustic instruments (i.e., most of the music in the classical and jazz genres). If you put a typical high-powered amp on Salons, the global feedback used to stabilize the circuits in such amps is clearly audible. If you search the threads, you'll see a lot of complaints about the speaker sounding lifeless and two-dimensional - that's because they tend to be demo'd with high-powered solid-state amps, often Levinson 300 series amps, which all use global feedback.

In short, the original Salons actually sound best, if the realistic reproduction of musical instruments is your goal (as opposed to shaking the neighborhood with home theater content), with lower powered, 100 to 150 watt amps that feature fewer output devices (i.e., fewer output tubes or transistors) and preferably, little or no global feedback - these speakers are very revealing and transparent like few others, and you really can hear what the upstream components are doing. Perhaps because the original version of the Salons can now be found used for $4,500 used, people think that they can be used with any old equipment - they can't. 100 high-quality tube or solid-state watts really lets them play music. If you want to reproduce dinosaurs stomping, and they can certainly do that very well, too, then run them with huge solid-state monoblocks, but if you want music, put a high-quality, zero-feedback tube amp on them - they can be really good speakers. As for the Salon 2, I don't have any meaningful time with them, but would imagine that they're even more demanding of quality amplification given their beryllium tweeters.
Raquel:

Looks like there's still hope. It's worth a shot anyway. Someone else here (Ral) suggested giving the Salon 2's a listen with the Triton before going for my second speaker option. A point he brought up though is that the speakers might go to 3.7 ohms at lower frequencies despite a 6 ohm nominal rating and that this might be a problem. If this turns out to be true, what would be the result of the 'problem'?
Deltatrippers:

These days, a dip to 3.7 Ohms in the bass is almost considered moderate given how many speakers drop below 3 Ohms (and even down to 2 or below). To answer your question, the problem with most tube amps driving speakers featuring large impedance dips in the bass is that the amp can't deliver enough current to control the woofers - bass response is flabby and ill-defined.

A real-world example is all of the people out there trying to drive WattPuppies with $4,000 tube amps and getting Sony rack-system bass. Perhaps the best example is the CAT JL-1's mentioned in one of my previous posts, which were the original CAT monoblocks from the late 90's and only rated at 100 watts per channel - they were designed to drive the very inefficient MBL 101B, a speaker which also features wild impedance swings. The output transformer alone in these 192 lb. amps weighs 55 lbs. The bass performance of those amps sounds like a 500 watt Krell. Here is an interesting thread that discusses the CAT amps at length:

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1099200096&openfrom&1&4

My best hi-fi buddy ran the CAT JL-1 Limited Edition amps (the LE's were $50,000, featuring incredible parts quality) for a few years and they are indeed the king of the jungle. With big symphonic music, a high quality DSD recording, and high-output speakers, they will knock you through the listening room wall on peaks.

I do not know how the Triton would perform with low impedance speakers, but it uses KT88 output tubes, which are difficult to make, the result being frequent tube failure. With KT-88's, it's all the more important to have a knowledgeable, reputable supplier.
I have used speakers that are very close to yours(85db, 6ohms.) The Harbeth SHL5's and now the M40.1's. The Manley Snappers were killer good with the smaller SHL5, but IMO not enough juice for the bigger M40.1. The VTL's have worked out great for me with the M40.1. I would put both on your list if looking for nice, affordable and very good sounding tube amps.