Tube vs Solid State Is the War

[fas42]

If I'm reading you correctly, you're talking about transistor crossover notch distortion? If so, that's nothing new and been known about for what, a couple of decades? And in that time, solid-state designers haven't figured out a solution?

As Tim ably pointed out, engineers, especially ones who are well past the need to sound technically impressive, tend to be a bit casual with their language, so I will straighten my tie, and attempt to be a bit clearer.

Transistor notch distortion can be a problem, but as you implied it has been "solved" for many years. There are various techniques, each amplifier designer has his own favourite combinations of methods to achieve a reasonable outcome: look up the literature by Self, Cordell, Duncan, etc. As a start, they use variations of local feedback, bias control and global feedback to do the job.

But that's not what I'm talking about: in most of these solutions you still have the situation that the power supplies have to supply high levels of current to the output devices while they are "on", and then switch that current flow off very abruptly when the device is "off". The current waveform through the output device is like a rectified AC voltage, a sine wave with the bottom half chopped off. So, if you do the maths on this waveform you find it full of very high frequency components, well past the audio range if amplifying high frequency musical tones at high volume, and the lower the bias the worse it is.

Now if the engineering has not been done adequately, the power supplies may not be able to cleanly deliver this type of current waveform, and to make matters worse, those very high frequency, relatively high current signals inside the amplifier can interfere with parts of the circuitry, and generate significant levels of high frequency distortion -- the sort of unpleasant noises that make some people less fond of class AB SS ...

Something close to pure class A doesn't do this, and tube amps rely on varying high voltages rather than large currents, also meaning less of a problem.

Frank

 

[JackD201]

Is it me or are you actually making a strong case for tubes being easier to implement for less money Frank?

 

[fas42]

Is it me or are you actually making a strong case for tubes being easier to implement for less money Frank?

Gee, it's half a dozen, and six of the other, Jack. As Mark (mep) has frequently pointed out, there can be a lot of trauma with using tubes, they age, only last so long, sensitive to speaker load, personally I don't like the fact that they are a friction fit in the unit, not hard wired. I wouldn't go that way myself; obviously if you do everything right they are very impressive, but I would never feel comfortable using them.

Frank

 

[MylesBAstor]

John and Jane Q Public have always driven the market, Myles, and it has always been driven by convenience. Convenience is exactly what vinyl was all about. But none of that changes the fact that there is no audiophile market for solid state amplifiers built to sound like tube amplifiers. They are two separate camps, as is illustrated by this thread and a thousand like it. Is it absurd to believe those camps won't cross over in significant numbers because someone can build tubes that sound like SS or SS that sounds like tubes? I think it would be naive to believe anything else. But your mileage, of course, may vary.

Tim

No because there are some people that no matter how good tubes sound, and willingly admit to that, will never buy a tube products (s). They don't want to deal with the issue of replacing tubes every year or two or three, depending up usage. Or they don't want to deal with the issue of heat (unless you're dealing with one Dan's Class A designs ). Or weight. Or size. Or worrying about the quality of the tubes. Or maybe the reason most often given: reliability (despite evidence to the contrary with the modern gen of tube products).

Then of course, there's those of us who don't want their tube amps/preamps to sound like their ss counterparts, just music. And if there was a ss amplifier that I could afford that gave me the same musical satisfaction and the same long term, fatigue free listening experience, I would have to give it serious consideration. But I haven't had one come my way yet.

 

[MylesBAstor]

The term "tube like" is a common term. One of the highest honors bestowed upon a solid state device. Hybrid is an attempt to marry the virtues of both camps.

Hybrids remind me of the Russian geneticist T.D. Lysenko's experiments. To appease Stalin, do honor to the cause of Communism and feed the masses, Lysenko proposed crossing, because they are of the same family, a radish with a cabbage; what he envisioned was a plant with the head of the cabbage and the bulb of the radish. What he ended up with, though, was the leaves of the radish and the roots of the cabbage Whether it's true or not is inconsequential; it's what the result of most hybrid designs turn out--with a few exceptions (and know you like your Moscode ).

 

[JackD201]

Most hybrids are gritty (radish leaves) and have less bass control (cabbage roots)? That would make sense if most had SS input and driver stages and tube output stages but from what I've seen most configurations are the opposite.

 

[Gregadd]

Hybrids remind me of the Russian geneticist T.D. Lysenko's experiments. To appease Stalin, do honor to the cause of Communism and feed the masses, Lysenko proposed crossing, because they are of the same family, a radish with a cabbage; what he envisioned was a plant with the head of the cabbage and the bulb of the radish. What he ended up with, though, was the leaves of the radish and the roots of the cabbage Whether it's true or not is inconsequential; it's what the result of most hybrid designs turn out--with a few exceptions (and know you like your Moscode ).

To continue your salad analogy Myles. Most salad dressings are mixtures where the original quality of the ingredients are lost. What you need is an emulsion like Italian dressing. All the ingredients maintain their original character.

 

[microstrip]

The answer to that is simple: There's no market for it. Those who believe in the superiority of tubes have never accepted the success of the Carver challenge, and the last thing those who believe in the superiority of SS want is an SS amp made to sound like tubes. In this age, you could probably create a SS amp with digital modeling circuitry in it to emulate the sound of Lamm, Conrad Johnson, etc, and a few of the more famous SS amps (though they'd all sound enough alike that it wouldn't be much of a challenge). But the people who even know what Lamm, Conrad Johnson, etc, is wouldn't believe in the concept and wouldn't buy the product. Why do you think the guy who made a relatively inexpensive SS amp sound like an esoteric tube amp is now building tubes?

He wants to sell some amps.

Tim

IMHO, the absence of market is really a very poor excuse for the single and unique experiment.

But in one point you are correct - why would Bob Carver be interested in developing better amplifiers if most of his supporters claimed that all current competently designed amplifier sounded the same?

 

[Ron Party]

Why would any tube amp designer want to perform this trick?

Well, I'm going to break a promise to myself to not feed the trolls. The simple reason, amongst many, would be for the same reason Carver undertook to do what he did. Now please follow along and re-read the question raised by Greg in his OP.

 

[Ron Party]

Oh, I see I forget to add AFAIK before the sentence (and any other in this particular debate, as we are discussing poorly documented facts - I only read the magazine reports).

No worries. In the few pages in this thread immediately preceding your post, a few of our members raised an issue concerning the posting of an opinion as fact. Given that background, I read your post as containing a rhetorical question:

Why until today no other designer of transistor amplifiers has managed to repeat the trick? Should we believe that Bob Carver was the only magician?

************

If you know otherwise please educate us.

I did not make the claim. I am following this thread closely, seeking to learn from others who have more knowledge and/or experience than do I. Regrettably there is very little knowledge being imparted thus far, save that which Mark has contributed.

Apparently now it is a given that you do not know if any tube amp designer has manufactured a tube amp that was found to be indistinguishable from a SS amp in a blind test. If any of our other members know of such an example please contribute your knowledge on the subject.

 

[mauidan]

Well, I'm going to break a promise to myself to not feed the trolls. The simple reason, amongst many, would be for the same reason Carver undertook to do what he did. Now please follow along and re-read the question raised by Greg in his OP.

Carver is back in business selling tube amps.

Why don't you contact him and ask him if he can make his new tube amp sound like a your favorite SS amp.

 

[cjfrbw]

It always surprises me the tenacity with which audiophiles on the boards cling to that old "Carver challenge" from Stereophile, believing that it actually demonstrated something about making a solid state amp sound identical to a designated tube amp.

Carver himself has stated publicly that he regrets that period of his career where he was most interested in gaining publicity for himself by engaging hyperbole and a bit of hucksterism. His main regret is that he feels it forever banished him from serious consideration as a genuine high end designer.

The so called "transfer function" was just a 1 ohm resistor placed across the speaker outputs to make the amp in question an undamped transistor amp instead of a transistor amp with a high damping factor, a feature of his amplifier series which he later designated as "voltage" amp rather than a "current" based amp rather than "tube like" vs. "transistor like". The distinction was apparently supposed to optomise the amp for planar vs. dynamic type speakers.

In any event, at the time of the challenge, it should have been obvious that a true, modeled "transfer function" would have required sophisticated, fast response computer modeling incorporated into the amplifier, a feature that the amplifier apparently did not possess at a time when such computational power was very expensive and bulky.

 

[Phelonious Ponk]

It always surprises me the tenacity with which audiophiles on the boards cling to that old "Carver challenge" from Stereophile, believing that it actually demonstrated something about making a solid state amp sound identical to a designated tube amp.

Well, I don't think anyone here is clinging to any belief that the Carver challenge demonstrated anything more than the obvious -- that with a few pretty minor tweaks and some null testing, Carver created a SS amp that a couple of golden-eared audiophile journalists couldn't differentiate from the high-end tube amp that it imitated. Does it prove anything more than what happened with those 2 guys and those 2 amps? Nope. But it sure informs a discussion which often borders on the metaphysical and seems to be saying that the difference those two distinguished audiophiles couldn't hear is obvious to anyone with ears.

Tim

 

[KeithR]

I really don't get all the discussion about Bob Carver in general. Has he been relevant sans mini subs in the past 20 years?

Sheesh, let's move on.

 

[Steve Williams]

Keith

I agree

The debate between solid state and tubes IMHO is getting old with the same old players and the same factions saying the same old things which does nothing whatsoever except to consume bandwidth with these old and tired arguments.

To me it's simple. I like it all, digital, analog and tubes and play whatever moves my juices at the time.

For some to say, "wrong, wrong" or that one just sounds like music whereas the other doesn't is again nothing more than a preference.

For one side to try to convert the other side to their own is foolish, childish and just plain boring.

So in order for all of us to wake up and smell the roses I am going to close this thread as IMO it has gone on too far with members bashing on others in order to inflict their own strong points of view.

Keith is right

C'mon guys surely you can all see that this is a no win situation. What grieves me more than anything else in threads such as these is that highly intelligent members are suggesting that "listening trumps science" and we really should all know better than this.

It is my strong intent that going forward any new threads on tubes vs digital or analog vs SS will be closely moderated and will be closed if the same nitpicking by members continues. I for one am all for listening but will never suggest that science doesn't know it all and that listening rules supreme