John Curl's Blowtorch preamplifier part III

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Yes same here, and since I was a kid. Battery types made a difference too I noticed.

Another thing I noticed as a kid is that the polarity (orientation) of the standard reversible Fig 8 AC power cable makes a further difference. I have tested this over time with a large range of 'portables' and same result. Perhaps somebody has theories as to why this is ?.

Dan.

Maybe because a battery is lower impedance than a electrolytic capacitor ? I certainly cant tell difference between car radio and mains radio. And I cant explain why figure of 8 cable reversed makes a difference. I tried my radio both ways around and it sounds the same.
 
Current noise induced by signal current and having decay and spectral characteristics.

Sorry, "current noise induced by signal current" doesn't compile at this end. However, I am now pretty confident we have a gap here between your understanding and the mere mortals EEs understanding of "excess noise".

Could you be more specific, some examples will be great.
 
Well T, maybe you have a good point. However, just this Sunday they had a lithium battery fire at the Tesla factory plant in Silicon Valley. IF they can't handle it, who can?

Chasing maximum energy density is always going to be a little dangerous. I'm sure you could make an exceptionally safe cell and pack but you're going to be losing some capacity, and that's the figure of merit for lithium ion / polymer batteries right now.
 
Sorry, "current noise induced by signal current" doesn't compile at this end. However, I am now pretty confident we have a gap here between your understanding and the mere mortals EEs understanding of "excess noise".
Could you be more specific, some examples will be great.
Ok, conductance noise of resistors is one example that has decay characteristic and spectral nature.
By applying 'dithering' of sorts this and other system noise characteristics can be changed at will.
I have recordings where I am able to discriminate this difference perfectly clearly, I am still working out how to post analyse it, CSD would be useful I think.


Dan.
 
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There are behaviours (excess noise is one) that are not revealed by stationary signal excitation ie sine wave excitation, however the ear readily picks up on these errant behaviours.
THD/IMD/N numbers and associated spectral analysis go some way to describing how an item or system sounds but not all the way, CSD plots of excess noise would go further.

Dan.
What are model and brand names of DAC, preamp, amp and cables that caused such audible difference?
 
Scott, do you know who Lev Landau is? Now, if Pauli insulted him, it is because Pauli did not understand him at the time. Landau is far more powerful a physicist to be put aside, except by someone prone to put others down in the same way.
It reminds me of a short discussion with Barrie Gilbert that I had with him at the ISSCC conference that I attended in 1974. I tried to relate what I had surmised about TIM to him and Barrie thought that I was NUTS! Of course, I was already gaining fame from my Levinson JC-2 preamp that was recently introduced, and that incorporated Matti Otala's suggestions, and in return had 100V/us slew rate on the line stage, for example. Of course, about 20 years later, a begrudging Gilbert gave Matti Otala some slim praise, and then went on to mathematically prove with hard calculations Matti Otala's PIM distortion prediction some 15 years earlier. He who laughs last, laughs best! '-)
 
Or a simpler story of Landau and Pauli is one of a student learning and a grouchy professor. I certainly wouldn't read any more into that. Goodness knows how much crap and sophomoric understanding I went through (ahem, go through). Certainly I'm no Landau, but I don't see much in it.

Sorry, John, Gilbert's legacy is enormous. Trying to justify yourself by kicking his grave seems a bit crass.
 
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What are model and brand names of DAC, preamp, amp and cables that caused such audible difference?
I am fitting filters to power and/or signal and/or speaker lines.
Every item or system that I have experimented on exhibits changes....the list is long.
Try a close listen to typical clip-on type ferrite filters....system noise gets cleaned up but there are new or newly audible remnants that are non musical/harsh and don't belong.


Dan.
 
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