I think I've made up my mind

Tvad,

Understood.

My recent move from an amp with 62K input impedance (Musical Fidelity A3CR) to one with a 100K input impedance (BC ref1000mkii) produced a difference in sound of the type and magnitude that would seem to support this theory and the physics behind the theory makes sense to me.


That's not to say that such a change in a single spec assures better sound, but the effects may be somewhat predictable in the case of impedance matching when heard I believe, which is of benefit.

The change in sound in my case was a marginal but noticeable improvement in overall clarity, dynamics and detail. That is pretty much what I was looking for in going to a SS amp (class D in this case) with higher than average input impedance specs that appeared to be a safer if not necessarily better match with a tube pre-amp.

Whether the resulting sound is better or not is always a matter of taste and preference and other technical factors as well. Specs are a guideline to better sound perhaps in some cases (like impedance matching) but only tell part of the story.

I think one of Bel canto's rationals for the design of the mkii version of the Ref 1000s was to help assure an optimal match with more pre-amps, tube pre-amps in particular. The input impedance was raised from standard IcePower 10K input impedance in the original ref1000s to 100K (unbalanced)in the newer mkii versions, which is largely why I sprung for the much more expensive mkiis over the originals, to help assure optimal results with the ARC sp16 pre-amp in my system.

Since higher input impedance always appears to be better, why don't SS desingers provide 100kohm input impedances. I would think the problem is that to do so requires a tradeoff they are not willing to make, but I don't know what that might be -- anyone?

Ack, The discussion regarding the ARC Ref 3 and Pass amp is exactly what Spectral wants to avoid. I am in fact a believer in not only the sonic matching of components, but also the electric matching which is where the system is either make or broken.

Pubul57,

Some (like ARC in their SS amps) and others do provide that.

Some do not.

Hopefully someone knowledgeable in SS amp design can chirp in and clarify what the tradeoffs are.

I guessing it has something to do with what is required to deal with distortion cost effectively then in the amp itself (negative feedback , etc.) in conjunction with driving lower impedance speakers effectively as well.

And/Or it might be that certain amps go for a certain type of sound that can be achieved more consistently with lower input impedance and a SS pre-amp.

I suspect part of the bottom line is just that no two amps work exactly the same way and synergy among components (pre-amp on one side and speakers on the other) then is always key as a result.

Pubul57, Perhaps the better question is why; don't high end manufacturers comply with the highly compatible pro standards?