solid state vs tubes

There is a technique in image processing called contrast stretching. Essentially it means if you clip off the extreme bright and dark extents of the image or picture, you can then stretch out what remains and often show subtle contrast details that are otherwise not apparent. Seems to me soft clipping as found with many tube amps and even some SS, operates similarly. Peaks are clipped in a softer manner that is more digestible to the ear. That allows volume to increase to higher levels than otherwise. Now more subtle variations can be heard in the rest also.

Now take clipping out of the picture by using an amp/speaker combo capable of achieving this at realistic listening volumes. Peaks go louder sooner (though are not cliped or distorted necessarily) and, ouch loud things can hurt now perhaps sooner rather than later because, hey those peaks are loud as they should be. But you now may need a really good ss amp with excellent resolution and detail in order to actually hear the subtle details because, hey things are not louder overall now so subtle differences in teh sound are harder to discern, especially if you do not have good ears and or a very quiet listening environment where what is played can be clearly heard.

Am I off somewhere in describing things this way?

As a corollary, here are a few factors that might push one into the stereotypical (no pun intended) soft clipping/tube amp camp rather than the stereotypical SS one.

1) recordings must be played too loudly in order to hear subtle details (increasingly common these days compared to past with many modern loudness wars recordings)

2) hearing/ears not what they could or used to be (typical as we grow older)

3) too much background noise to discern the low level details that might be heard otherwise

Please not that I do believe that, as Bob Carver seemingly demonstrated, SS amps can tweaked to sound like a tube amp if you have a way t accurately measure the differences and you have tthe knowledge to know what amp parameters or characteristics need to be changed to accomplish the goal.

As a consumer, the trick then is to do you homework and find a SS amp that plays better in this scenario than most S amps, and more like typical tube amps.

Mapman, I am **not** talking about clipping, although it is true that in clipping, tube amps generally make less odd ordered harmonics than transistors do.

What I am talking about is the fact that when you use feedback to control distortion, the price of the feedback is distortion of the loudness cues (5th, 7th and 9th harmonics). Not by much, but as I mentioned before, 1/100th of a percent is audible. It seems crazy to think that the ear is that sensitive, but after all, it has to be sensitive to *something* and this is the mechanism that we use to determine the volume of a sound! So when you see amps with very low THD, its likely that this mechanism has been interfered with.

The result: the SS/tubes controversy since SS amps usually use a lot more feedback than tubes do (which can be built with no feedback at all)- IOW tubes more closely mimic the rules of human hearing, and so make much less of these particular harmonics, even though they often make more of the lower harmonics (which the ear finds less objectionable, though they are often credited with the 'tube sound').

Its not so much that I prefer tubes, what I really prefer is amps that don't violate human hearing rules. So that is an amp without feedback, more than it is tube or transistor.

Now, without feedback, it might be better to have either a higher impedance in the speaker and/or a flatter impedance curve, but if that is the price to be paid it seems small if it is the difference between something sounding like a stereo and something sounding like real music.

Hmm, not sure I see a consensus that use of negative feedback is always categorically a negative. It seems to be debatable at best.

The soft clipping characteristics of tube amps in general seems to be pretty widely accepted. Soft clipping means that dynamic range is restricted to some extent as I understand. That means loudness cues are reduced relatively, all other things aside, as well, right?

The discussion here is equally facinating and confounding. Because the arguments are great. But, lets remember that original post was about whether in direct comparison between tube and solid state amps the difference was non discernable. Atmasphere as usual presents a well thought out technical discussion regarding the benefits of tube amplification and some drawbacks for solid state. As I pointed out, with well engineered/designed tube or solid state amps, I'll take either because a correct well engineered design is just that, regardless of whether it is tube or solid state. Most of the arguments (not all) against solid state really stems from the mass produced stuff produced in the 70s and 80s. It wasn't really terrible, it was just not really good enough for serious listening, but background music. I have several systems in my home that are used specifically for background music when I'm not doing serious listening. However, Bob Carver was correct in that if you give a good engineer enough time and money, they can make an amp sound like the best made. Just copy the transfer function of the best. But, solid state distortions vs tube distortions, come down to how hard the engineer wants to work to eliminate the worst kind of distortion and leave only distortions that aren't bad. Both in tube or solid state. Nelson Pass has an excellent article on his DIY Pass Labs site about this very topic. Wonderful reading. Compromises abound in this industry. How much time and money does the engineer have to work with? If unlimited, you will have a solid state amp that no tube amp can touch and the same can be said for a tube amp. I have heard some not so great tube amps and some not so great solid state amps. I have also heard some wonderful tube amps and some wonderful solid state amps. sooner or later I'm going to hear some Atmasphere tube amps and I bet they are absolutely great and I would be faced with the decision to go broke again for a short time or not. But, even when I'm sitting worrying about how much money I just spent, I ultimately end up smiling when I realize that the music is absolutely wonderful and life is good. First thing first. I know good music when I hear it and I can tell a bad recording or simply bad music when I hear it. I played classical violin (first chair), oboe, sax, and many other instruments. I know Jazz, R&B, rock, classical, etc. I know live unamplified music and have heard very good amplified music. So, I know what a real symbol sounds like. So, my point is when you sit in front of that special system and listen to music, does the singer come out on stage? can you see the stage? where is the piano?, drummer, etc? can you see it? how deep is the stage? If you can't see this, then 1) either something is wrong with your system, 2) something is wrong with the recording or a combination of both. but, you absolutely should know that something is wrong. I am a advocate of making friends with a very good stereo equipment shop and on occasion go in and listen to their best system (that you know is good) and reacquant yourself with what a great system should sound like, so you will know what is wrong with yours and work slowly in fixing (a piece at a time) yours. It takes years, unless you have a lot of money now. Enjoy the music. Life is short. Equipment come and go and does slowly improve over time. But, don't marry the equipment, marry the music. I really enjoy reading your threads.

enjoy