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Old 16th November 2012, 09:07 AM   #21
SY is offline SY  United States
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Quote:
Originally Posted by Merlinb View Post
If absolute fidelity is your goal (e.g., a fast efficient car), why use valves (e.g., T-Bird)? Answer: fidelity has surprisingly little to do with enjoyment...
For some, perhaps, which explains the popularity of effects boxes posing as amplifiers (and there's solid state effects boxes as well). For me, no, I want fidelity in my electronics and I have no problem achieving that with tubes.
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Old 16th November 2012, 09:34 AM   #22
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For me, no, I want fidelity in my electronics and I have no problem achieving that with tubes.
But no valve circuit will acheive the <0.001% THD, noise, power, efficiency, damping, and low cost of even a trivial SS amplifier. Hmm... so what you're saying is, you want some fidelity, but it doesn't have to be the most. You're happy with second best, just as long as it's not third or fourth best. What a peculiar philosophy...
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Old 16th November 2012, 09:58 AM   #23
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Originally Posted by Merlinb View Post
But no valve circuit will acheive the <0.001% THD, noise, power, efficiency, damping, and low cost of even a trivial SS amplifier. Hmm... so what you're saying is, you want some fidelity, but it doesn't have to be the most. You're happy with second best, just as long as it's not third or fourth best. What a peculiar philosophy...
Letīs not start a war here .

If we wanīt to compare letīs start with a zero feedback pre amp.

When it comes to current amplification the SS wins end of story !
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Old 16th November 2012, 10:05 AM   #24
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If THD is the sole metric, that's indeed true. If you take the attitude that below a certain point, it's not particularly meaningful in an auditory sense (that, after all, is the purpose of these components), then that's not very important and other factors rule.
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Old 16th November 2012, 10:24 AM   #25
DF96 is offline DF96  England
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Quote:
Originally Posted by Merlinb
But no valve circuit will acheive the <0.001% THD, noise, power, efficiency, damping, and low cost of even a trivial SS amplifier.
If you use the word 'trivial' with anything like its correct meaning then I would suggest that a trivial valve amplifier will always outperform a trivial SS amplifier in terms of listening quality. To improve SS you have to make it much more complicated. To improve a valve amp you only have to make it a little more complicated. You can eventually get the SS to surpass any valve amp in measured performance, but by this time both amps are well past the point where you can actually hear any difference with just your ears.
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Old 16th November 2012, 10:57 AM   #26
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what, no love for the pentode driver?

Anyway, there seems to be two camps of thoughts when it comes to tube amps. I've heard both results to varying degrees. A 300B amp that was so colored - it must have been pumping out just gobs of 2H distortion - that the character was evident with every recording. The owner thought it was the bees knees. Or a certain manufacturer whose tube gear might as well be solid-state. At least personally, I like to find a happy medium.
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Old 16th November 2012, 11:10 AM   #27
Merlinb is offline Merlinb  United Kingdom
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Originally Posted by SY View Post
If THD is the sole metric, that's indeed true. If you take the attitude that below a certain point, it's not particularly meaningful in an auditory sense, then that's not very important and other factors rule.
But if you ignore distortion, what other factors are left to measure fidelity?

Quote:
Originally Posted by DF96 View Post
If you use the word 'trivial' with anything like its correct meaning then I would suggest that a trivial valve amplifier will always outperform a trivial SS amplifier in terms of listening quality. To improve SS you have to make it much more complicated.
I dunno... it takes fewer than ten transistors to make an SS amp with gobs of feedback and outstanding measured performance. I consider that trivial.

Last edited by Merlinb; 16th November 2012 at 11:14 AM.
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Old 16th November 2012, 11:26 AM   #28
DF96 is offline DF96  England
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With two valves you can make a trivial amplifier which needs no feedback provided you don't drive it too hard.

Ten transistors is not trivial. Four or five maybe would be.
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Old 16th November 2012, 11:32 AM   #29
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With two valves you can make a trivial amplifier which needs no feedback provided you don't drive it too hard.
Ok, but exactly the same is true for transistors- e.g., Nelson Pass. I suspect the transistor version would have the lower distortion, since it would presumably have more gm available to be wasted in local degeneration.

Last edited by Merlinb; 16th November 2012 at 11:36 AM.
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Old 16th November 2012, 11:43 AM   #30
DF96 is offline DF96  England
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Local degeneration raises output impedance, the opposite of what you want in a trivial amplifier.

The problem you always have with BJTs (and to a smaller extent with FETs) is that they are essentially small-signal devices. A bare BJT will give you 1% THD with 1mV peak input voltage.
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