John Curl's Blowtorch preamplifier part IV

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I didn't think you could, no problem

It often helps to specify the question.....

@billshurv,

the basic (ok, it's a matter of definition wrt "basic") engineering does not help, as normal bandwidth calculations show that everything is ok.

I've said in the past that it would help to draw the most basic configuration of a signal source, preamplifier and an power amplifier with ground connections and asymmetrical interconnections to see where problems might arise.

IMO even basic engineering leads to the conclusion that this quite typical configuration is able to provide many open doors for common impedance coupling, interference - some selfinduced,some from the outside - so problems more likely than unlikely.
 
It often helps to specify the question.....

@billshurv,

the basic (ok, it's a matter of definition wrt "basic") engineering does not help, as normal bandwidth calculations show that everything is ok.

I've said in the past that it would help to draw the most basic configuration of a signal source, preamplifier and an power amplifier with ground connections and asymmetrical interconnections to see where problems might arise.

IMO even basic engineering leads to the conclusion that this quite typical configuration is able to provide many open doors for common impedance coupling, interference - some selfinduced,some from the outside - so problems more likely than unlikely.


Zactly. These are all measurable. Many without advanced equipment. I would make no claims for audibility but one could at least rank cables according to how well engineered they are for the task at hand.That would be a start.
 
So you jump straight into the flooby side without looking at basic cable engineering...

Bill,

There is a cable manufacturer who wraps a cellophane like material around the foil shield layer in some of their audio specific cables. This allows them to extrude the jacket easier and faster. Of course it makes the cable triboelectric like nothing else. Doesn't really stand out as a problem as it is meant to be an installed cable on low impedance circuits.

Of course if the cable path runs into vibration like from a ventilation fan the signal to noise ratio on microphone level circuits drops below acceptable levels. Most folks don't pick up the problem as it is generally at 20 or 30 hertz! But it does tend to overload inputs until the gain trim is turned down and the signal to noise ratio degraded.

So the problem does occur and is almost always ignored or missed.
 
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