Tube Amp for Martin Logan Speakers

Quicksilver, Quicksilver, Quicksilver, Quicksilver, and Quicksilver.... any of the larger variety will do a splendid job.

Bruce, I am a moderator on another site that is unrelated to audio. In that regard they put me through some training so that I could spot posts that went beyond the pale. I don't see Unsound doing that- he attacks the argument, not the person (which is how its done). IMO debate is fine and healthy- and is what forum sites are for. In the end, the debate can help people gain education or at least viewpoint on a subject.

George is different that he attacks the person (look for the word 'stupid' in his last post) and he will often negatively engage in topics just so he can get a rise out of other posters. That is one of the definitions of trolling. (As a side note its also pretty evident that he does not know what he is talking about WRT the ZEROs.)

This site does not employ a 'Report' function so its pretty hard to alert moderators when this sort of thing is going on- they have to encounter it on their own.

Unsound- I see that you reposted some earlier comments I made and one from Duke; I don't see exactly why though. Could you elucidate?

Ralph, as I have come to better appreciate, there are very few if any perfect solutions to audio technical issues. It seems that EE/designer folks like yourself make judgments and compromises to achieve a certain balanced product that has market value within its market niche.

For that reason, I think that it is imprudent to think in absolutes. Having said that, I believe that if one is looking to invest significant sums into their rig, they can avoid obvious pitfalls and clear mismatches, for example, matching a low powered SET amp or a high'ish output impedance tube amp with a low sensitivity rock n' roll impedance curve speaker, like my Paradigm Signature 8s.

(It's only through dumb luck that my Ref 150 can do a decent job driving these beasts. Should have picked another speaker, or kept the speakers and opted for a top drawer SS amp like a Pass or Ayre.)

So, I share your view. We are adults and should be polite, albeit a little tongue-in-cheek humor from time-to-time is ok by me. :)

By the way, I thought the primary focus of your comment about using ZEROs was with respect to matching one of your OTL amps with ESLs like Martin Logans which have extremely low impedance specs at high frequencies. Quite honestly, if I loved ML ESLs, I would have some agita matching that transducer with pretty much any amp, SS or tube, unless the amp was rock solid stable and wouldn't distort driving juice into a .5 ohm load.

Btw, btw, after having read your posts again, I changed the output taps on my Ref 150 from 8 ohms to 4 ohms ... again. Although gain was clearly reduced because I was using the 4 ohm taps (about 2.5 db less than the 8 ohm taps), I think it quite possible that the amp was producing cleaner power (i.e., less distortion).

Bass is clearly more extended and tighter. No surprise there since the output impedance off the 4 ohm taps is less than the 8 ohm taps (therefore higher DF). Plus, speaker impedance in the "power zone" (say 60 Hz to 700 Hz) is for the most part 4 to 5 ohms), ergo a better impedance match for the amp where it is being called upon to deliver most of its juice. Imaging was less forward (probably because midrange/treble was less emphasized as a result of higher impedance), so I turned up the gain and imaging came back. In short the rig plays louder, but not as harsh (i.e., maybe less distortion).

Regards to all,

Bruce

P.S. Back to audio business, I just bought a JVC hi-rez redbook CD of Tango music from Acoustic Sounds. I'll report back with comments. I'm trying to keep track of good hi-rez CD label. So far, +1 for MoFi.

Atmasphere, I included the quotes as per your request.
The first two from you to support my premise that I wasn't putting words in your mouth.
The ones from Duke (AKA: Audiokinesis) with re: to it being easier to steady an impedance by lowering the impedance (and ergo make for a smoother frequency response).
I'm having trouble with my old memory as to whom might have suggested that lowering the impedance could help with bass response (and ergo increase frequency response), so the search for that link might be considerably more difficult. Then again if we can extrapolate the words from a very articulate, very well respected (especially here on Audiogon) amplifier designer; that one can get greater sound pressure into a 4 Ohm load with a ss amp, then we can use that extrapolation to suggest that as frequency response is measured in dBs, one can extend bass response and therefore extend frequency response.:-)

Atmasphere, Ah ha, I found one, I'm confident there is at least one more from a different source. I'll keep scratching my head.
04-05-11: Lrsky
Soundlock makes a good point.
Jim Thiel, starting in 1988, while developing the CS5's discovered that, by using bass drivers that drop precipitously in resistance, that this had a side effect of pulling more current from the amplifier--acting 'almost' as an equalizer on the bottom/bass region.
I have not discussed this, but it seems plausible, AND if Jim said it to be true, I don't need much else to bolster this opinion.
So...with that said--an amp with lots of balls, doubling as the impedence drops more and more, as they do get into the 2 ohm region with the THIEL 3.7--should mate well with a 'Krell-like' bass performer. I don't ascribe to the Magtech amp, as I haven't heard it...yet, he's right on the mark in his assessment. THIEL's need current.
As a side note--one very hard earned lesson by Jim that year was, that virtually everyone exaggerated their current delivery on the amplifiers--very few did what the manufacturers claimed.

Good listening...

Larry
Lrsky (Threads | Answers | This Thread)