solid state vs tubes


has anyone compared a tube amp to a solid state amp and discovered that the diffference sonically between them was undetectable. ? if so what was the tube amp and what was the solid state amp ?

the reason for the question is the basic issue of the ability to distinguish a tube amp from a solid state amp.

this is especially interesting if the components were in production during the 90's , 80's or 70's.

if the components are in current production the probability of such aan occurrence might increasea.

why own a tube amp if there exists a solid state amp that sounds indistinguishable from it ?
mrtennis
"The break down rate on the tubes was only slightly higher retubing for my preamp was $ 550. per year , my power amp $2200. per year"

Wow, that's scary.

The tubes in my ARC sp16 are coming up on 2 years with a lot of play. I have had minor noise issues that I have alleviated by shuffling existing tubes, but I think the time is coming to replace all. From ARC, the cost of doing that is about $30 a tube or $180 dollars total for 6 12AX7s.

I really like the ARC but if I were shelling out hundreds a year just to retain the good sound, it would probably be out the door and back to all SS for me.
So many possible responses.
Isn't it true that when connecting to the various taps on a transformer that you are using more or fewer windings? Won't that change sound more than the load variations to a SS amp?
I like the talk of sensitivity and efficiency as different things. Also on the plate is impedance...and not just a single nominal number, but the range, along with min / max for any given speaker.
Than again, nobody has yet mentioned phase. I am told that Harbeth makes LS 3/5a type speakers and though they are about 83db sensitive, make a wonderful match for tube amps. Benign phase and moderate impedance range are key.
My panels should work with tubes, as well. Reasonably flat impedance curve and no wacky phase problems.

Naw, I think the concept at least is pretty simple. Compatibility / synergy can be chosen electrically. Magic happens when you get it REALLY right. It shouldn't take a lot of money for a good, basic, solid, good sounding simple system. No need to spend a bundle on cables, either.

Again, damping has come up. And nobody has mentioned speaker 'Q'. What role does the design of the speaker have in all this? Can't a critically damped speaker produce fine bass in an 0 damping factor system? I suspect so.
You don't need a DF of 10,000 to get good bass 'control', which is one of the red herrings of audio. A speaker with 'Q'=1.25 will be sloppy almost no matter WHAT you do.
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.