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Old 2nd May 2012, 10:00 PM   #5001
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Default Type of noise .

It's called need to have some sleep . Still does any of it seem reasonable ? 1/f noise in valves , yes . Is that so of transistors or is it more Johnson noise ?
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Old 2nd May 2012, 10:08 PM   #5002
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Nigel, you are outside your knowledge level. Do a little Googling on noise. All active devices have both 1/f and Johnson noise. It is just the ratio of each and the onset of the 1/f or the transition frequency, below which the 1/f dominates.
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Old 2nd May 2012, 10:13 PM   #5003
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Default Noise

John I risked that and knew it . Just wish I knew what Malcolm said . I wish Joachim Gerhard was in the debate as he told me . He seemed very convinced .
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Old 2nd May 2012, 10:16 PM   #5004
a.wayne is offline a.wayne  United States
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John,
Did you look at any of the links I posted .. Thoughts ..?
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Old 2nd May 2012, 10:22 PM   #5005
FrankWW is online now FrankWW  Canada
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Low level noise is not trivial in masking/modifying effects of low level sound.

Get a a white or pink noise source you can run separately from your system and put it near your speakers. You will be surprised at how little you have to turn it up before it affects your musical experience.
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Old 2nd May 2012, 10:28 PM   #5006
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Default Joachim Gerhard

Joachim your in box is full . Your moment for glory has past .

Perhaps it was this .

AES E-Library Ultra-Low-Noise Amplifiers and Granularity Distortion

Last edited by nigel pearson; 2nd May 2012 at 10:39 PM.
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Old 2nd May 2012, 10:39 PM   #5007
a.wayne is offline a.wayne  United States
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You can find him in the SSA thread ... ....
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Old 2nd May 2012, 10:40 PM   #5008
bcarso is offline bcarso  United States
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Quote:
Originally Posted by DF96 View Post
I doubt it. I would expect that a cascade of stages, each with a smooth gain curve around zero-crossing, has a total gain curve which is also smooth although perhaps slightly less smooth. This assumes that there are no mathematicians' pathological functions lurking around.

I would not want to do a proof, but I expect that the product of a few rapidly-convergent smooth infinite series is itself a rapidly-convergent smooth infinite series. Distortion will then be monotonic with signal level, for sufficiently small signals.
If the nonlinearity is truly time invariant I'd tend to agree (and that's one of our tacit assumptions).
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Old 2nd May 2012, 10:41 PM   #5009
bcarso is offline bcarso  United States
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Quote:
Originally Posted by nigel pearson View Post
Joachim your in box is full . Your moment for glory has past .

Perhaps it was this .

AES E-Library Ultra-Low-Noise Amplifiers and Granularity Distortion
And I was hoping that someone would mention the "granularity" stuff.
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Old 2nd May 2012, 10:49 PM   #5010
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well you can expand to include slowly time variant nonlinearity too where the time constants are less than the nominal circuit speed - then the slow time variance is separable in the perturbation theory sense - one reason I really can't get excited over Lavardin/"memory distortion" from thermal device modulation - just too slow relative to feedback amp dynamics to have effects worth worrying over in a high feedback amp

of course low local feedback only amps could have thermal drift transfer function modulation of operating points give possibly audible response changes - clear win for global high feedback

the only class of time variant/memory distortion I see to worry about is hysteresis

Last edited by jcx; 2nd May 2012 at 10:54 PM.
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