Looking for advice on these speakers

Al, I may have asked this question some time ago.

The output stage coupling of most ARC tube amps, at least my Ref 150, "is a combination of 'ultralinear' and Audio Research’s patented 'partially cathode-coupled' topology, which is superior to conventional pentode or triode operation." The foregoing cite is off of the ARCDB web site link to the Ref 150.

I have absolutely no idea what ARC is talking about, but suspect it may be a form of local negative feedback of sorts. ARC also touts that its circuit topology makes for better performance than "conventional pentode or triode operation." No comment.

I mention that here because of your last several posts which recommend caution in using some very low power SETs, especially if the amp will be called upon to drive dynamic music. Certainly, there are higher power amp options that may get one close to the presumed benefits of a SET amp, e.g., Ralph's zero NF OTL amps, or VAC amps, etc.

Maybe you can push the fog away.

Hi Bruce,

Yes, as Ralph had indicated here the ARC topology you are referring to is indeed a form of feedback. I have no idea, though, if that topology would cause the resulting sonics to be to some degree more SET-like, or if its presumed benefits might be in some other direction.

Best,
-- Al

I'd suspect that a circuit that is reliant on a feedback loop(as Ralph described) is not in the direction of SET sound (generically speaking). One of the "major" attractions of SET amplifiers is their simplicity and lack of need for NFB. Now which direction one chooses to follow is certainly individual choice.
Charles,

Al and others, I appreciate that adherents of low power SET amps believe, and perhaps with some justification, that the benefits outweigh the downsides (e.g., low power output).

My only point is that opting in favor of that direction necessarily limits the universe of speaker options -- that is, speakers having high sensitivity specs. I'm not sure if SETs also have high'ish output impedances, but if so, then other trade-offs may be required.

I for one like flexibility and options. My bias (pun intended) would be to shy away from this class of amps.

Flexibility limitations can exist in both directions (inevitably). Low efficiency speakers lessen the choice of amplifiers that can drive them. Honestly either option can work out successfully. Fortunately there are enough fine high efficiency speakers available to satisfy the low power amplifier aficionados among us, so all is good.