GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Melquiades Amplifier
In the Thread: Single-stage Melquiades vs. DHT amps

Post Subject: Tubes, Whole Circuits, Expectations and SoundPosted by Paul S on: 2/14/2009

It sounds like a lot of the circling has to do with which 2A3 "sounds better", outright. In any case, I'm guessing everyone would agree that it is specious to argue about which 2A3 sounds most like some internally-established aesthetic benchmark for 2A3s. I certainly hope no one cares about that. The idea is to get the "Best Sound", period; right?

The fact is that "new 2A3s" are often thinly-disguised 300Bs, and they can easily up the ante with respect to power, which often gets short shrift from flea-power afficionados. Well, if it's power one wants from a 2A3, then why not start out with a clean-sheet design based on one of the new breed of "2A3s"?

As it happens, I prefer the best part of the "neutral" sound "character" of old, tres-expensive 45s to anything else I've gotten to listen to long enough to establish a sense of its contribution to the sound. Yet, I have never actually owned a 45. The reasons for this are purely practical; basically, it lacks the range and power to drive acceptable speakers well enough to play Music to my satisfaction. The 45 sounds great; but it can't make great Wagner. And as I progressed with the more-powerful 2A3, I wound up with the same problem, even with A-2 via the very-hearty older Sovteks (which the circuit was built around, BTW). I can only guess whether others have FR speakers that are somehow efficient enough to overcome the problems I encountered; but I have my suspicions...

With respect to circuit design, one of the most facinating things I have learned about electronics for hi-fi is that any theoretical solution to a given problem requires an all-inclusive, 4-D, total-system perspective; and still one is apt to wind up scratching one's head at results. From Miller Effect to ESR, on and on, real world circuits are "dynamic" in every sense, and they are in every sense woirthy adversaries, to say the least. For instance, although I have no idea where the actual power goes, I have begun to see a pattern of diminishing net returns with respect to the smaller SETs, to the point where I wonder if their "potential" can ever be practically realized as Music in Full Glory.

Regarding 2A3 selection, my impression here is that we all +/- understand the in's and out's of operating points; but we all have different systems and it sounds like we also have different expectations at this time.

Lastly, the choice of an output tube for MF-only DSET for a single 109 dB horn-loaded compression driver casts an entirely different light on the subject, I think. If there is a real possibility, then this might be close to a case where one need only look at the straightest part of the plate curve of a 2A3 (or 45) and build to that, irrespective of "power". I have had some luck adapting phono stages this way; but so far, no keepers from amongst the small SETs I've played with.

Paul S

Rerurn to Romy the Cat's Site