solid state vs tubes

Unsound, Paul Speltz who makes the ZEROs has a letter from Steve McCormick, in which Steve asserts that his amps, which have no problem with 4 ohms at all, sound better driving 4 ohms through the ZEROs.

Upon hearing about this (which was about 2 years ago) the next time I was at CES I asked about this subject with several of my friends in the industry who make transistor amps. I was surprised that there was a consensus amongst them, that I can paraphrase (this one stated almost verbatim from Edge's Steven Norber) 'just because it is comfortable driving four ohms does not mean it is sounding its best', this specifically in relation to 16 ohms.

One thing that you may not be considering is the role of the speaker cables, which is critical with 4 ohms but not so at 16 ohms. For example if you do the math, you find that no matter how high the damping factor of the amp, there are no speaker cables that will allow the amp to express anything more than 250 into 4 ohms.

In short, in high end audio there is no compelling case for 4 ohms. Its bad for tubes, bad for transistors. How this might relate to MrT's inquiry is that his job would be easier were he to use a higher impedance speaker.

BTW, I do concede that in my comments 'all other things being equal' is a serious caveat. They never are. Because of that, it took a long time to figure out how important this issue actually is.

Finally, I would like to point out to MrT an issue that must be considered: speakers that are designed to work with transistors may not work with tubes, and vice versa. This is an old conversation, that of equipment matching, but touches on a larger subject:

http://www.atma-sphere.com/papers/paradigm_paper2.html

Atmasphere, auto-formers aren't a new concept. The only ss amplifier I know of that includes an auto-former appears to do so in an effort to adapt to an otherwise speaker mismatch. If auto-formers were of such benefit and without deficits, why wouldn't they be included in all original amp designs? Or if not amps, why not original speaker designs? Of course we don't listen to amps, but speakers powered by amps. That para-phrased statement of Mr. Norbert is quite a bit different than claiming that ss amp sounds better into higher impedance loads.
What aspect of the speaker cable is this attributed to?

Unsound, in this case Mr. Norber was telling me, as did the other manufacturers, that indeed their amps do sound better into higher impedances, despite making less power.

The Mac autoformers are used to load the transistors at a lower impedance if I recall right, quite the opposite of what we are talking about. I have to tell you, I was quite surprised to find that the ZEROs have a benefit to transistor amps in the same way that they do for tubes, although when it was pointed out that this has to do with the behavior of the output devices when more current is put through them, it makes perfect sense.

With regards to speaker cables, it appears to be simple DC resistance.

hi mapman:

the issue of discerning the difference between a tube amp and a ss amp, ceteris paribus, is of great interest to me.

if i can be foooled or cannot tell the difference between a ss or tube amp as party of a stereo system, why have the tube amp.

ralph: i thinki the issue is planar vs cones , not impedance.

it may be harder to tell the difference between amps using cones, than panels, regardless of a con designs impedance curve.

in my case , a planar owner, i think it is easy to tell the difference between ss and tube amp. electrostats and ribbons do not have the same impedance curve, yet they are -panels.

i have heard rowland and avalon sound very pleasant , when combined, but i have yet to hear a panel speaker with a class d or ss amp drive an electrostat or ribbon, or planar magnetic exhibit a well beheaved upper midrange, treble response.

i realize it is preference and i expect that finding a ss amp that will be livable is almost impossible. i have no illusions, but will not give up the quest, as yet.

Mr T.

That's fine I think you need to state the question as might your speakers sound tube like with a ss amp. Nothing else really matters if that is what you seek.

I personally think it is possible with some SS amps, maybe even the better Class Ds. You might want to through some tube gear up front in the pre-amp or source in order to keep things leaning more towards the pure tube sound, but I'd be willing to bet you can do it with a SS pre-amp and maybe no tubes at all.

I would not hesitate to suggest trying the Carver m4.0t that I used with mg1cs for years with no real tubes. A used one would only cost a few hundred. Or maybe even a m1.0T which is the amp that was voiced to sound like the CJ reference amp. My only reservation with this combo was that a sub was needed for the low end to be competitive with truly top notch systems in that regard.