Thoughts on Tube vs SS amplification for Sony SS AR1s

If you could find a used Adcom 535 you see how your speakers react and then sell this amp for nearly what you paid. This is the only amp that Adcom made that I liked. In fact this amp powers my garage system. I also owned the 555 and the 565s but could never warm to the sound.

Hi all
Per the advice everyone has provided I am looking into some separates that have reliable specs for power into 2 ohms (seems like there are a number of good options here) - will definitely report back as this is an interesting subject. 

Thanks!

Hi All,
I know it's been a while, but I thought I would report back as so many of you gave me helpful advice. I had a chance to try the SS AR1s with a very capable Accuphase integrated and the results were clear and surprising. 

Relative to the tube-based Luxman LX380, the solid state (and much more powerful class A/AB) Accuphase was muddy and muffled (and I say this as someone who was highly biased towards the Accuphase and was anticipating great things). As soon as I swapped them I could tell something had happened to the mid and high end of the spectrum - things were not nearly as clear or articulate - it was like there was a veil of something in between the music and me (really obvious on things like voices and acoustic guitar for example). I really can't think of any better word than 'muffled.'  I thought perhaps I was mis-hearing things so I had my wife do a few casual tests with her back to the equipment, and unprompted she made the same comments about "amp B" (the Accuphase).   With the Accuphase I certainly noticed a bit more definition in the lower registers and bass lines had a bit more clarity to them, but a) the difference wasn't like night and day relative to the Luxman (they were very close), and b) it seemed to involve a massive trade off for what I can only describe as 'transparency' in the high end. with the Accuphase in place vocals and acoustic instruments sound like a thin door has been closed between the music and my listening position (honestly)

I am really surprised/stumped as to the results, as I had high expectations for the Accuphase and the SS AR1s. This Accuphase amp is highly regarded and in all the literature I read I would never have expected this outcome, but that's what my ears told me in the end. Obviously this is all down to individual taste and opinion, but the clarity of the Luxman was not bested by this entrant.

re next steps, I guess im looking at either something like very capable SS mono blocks (like the Marantz ma9s2) to see if that can overcome the acuphase's shortcomings, or a more powerful tube amp (which again, on paper, shouldn't play this well with the SS AR1s, but there you have it) - still not sure how the LX380's specs on paper should be working this well with these Sony's, but they sound far superior to the first SS contender~

Till next time!

@sfmorris,
There could be something wrong with the Accuphase.  It should not sound muddy and muffled.  You may want to check on that possibility before moving on.

I am really surprised/stumped as to the results, as I had high expectations for the Accuphase and the SS AR1s. This Accuphase amp is highly regarded and in all the literature I read I would never have expected this outcome, but that's what my ears told me in the end. Obviously this is all down to individual taste and opinion, but the clarity of the Luxman was not bested by this entrant.

In a nutshell, high damping factors are overrated! Duke LeJeurne of Audiokinesis gave an excellent reason why (as a speaker designer):

" A high damping factor will provide very good control of the bass drivers."

Hmmmm.

For a quick summation of my thoughts, skip to the last two paragraphs. Apologies for getting fairly nerdy in between here and there.

In practice, any series resistance in between the amplifier and the woofer’s voice coil effectively ADDS TO the amplifier’s output impedance, and correspondingly reduces the damping factor.

Let’s run some numbers. Supposes our speaker has a nice 2.5 kHz second-order crossover, which calls for a 1 mH inductor in series with the woofer. Power handling requirements are easily met by an 18 gauge air-core inductor, which can handle 300 watts before saturation. The series resistance of this inductor is .51 ohms.

And let’s suppose we have an uber-amplifier with a damping factor of one zillion. Or one zillion zillion. Or one zillion to the zillionth power. It won’t matter.

After the signal passes through that inductor, our uber-amplfier’s amplifier’s effective damping factor is now about 17. And this is assuming only the one series inductor, and ignoring any other wiring.

So in most cases it really doesn’t matter how high the amplifier’s damping factor is. The series resistance in the crossover (and/or speaker wires) dominates.

Okay, but what about this "very good control of the bass drivers" that we’re apparently missing out on?

Well, turns out that it’s not nearly as dramatic as the wording implies. It all shows up as a change to the electrical damping of the woofer’s motor - the electrical system Q, or Qes.

Assuming a typical high-quality 8-ohm woofer in the example above, the series inductor effectively raises the woofer’s electrical Q by about 7%. So if the woofer’s electrical Q was .28, the series inductor effectively raises it to about .30. This could EASILY be an improvement! We'll get more bass with a higher Qes, but the designer should take it into account by sizing and tuning the box based on our modified Qes of .30. And if he hasn’t, this difference can still be largely compensated for with a few handfuls of stuffing material.

I think amplifier marketing departments may have oversold the benefits of having a high damping factor.

Or to put it another way, in my opinion, super-high damping factors are, in most cases, of academic interest only. I certainly would not trade off anything that really matters in order to get a high damping factor.

Duke

This post is fromhttps://forum.audiogon.com/discussions/how-to-accurately-gauge-speaker-sensitivity-to-match-with-tub...

Our most popular amps have a fairly low damping factor- if DF were that important, we'd have been out of business decades ago.