The problem my friend is almost certainly facing is the parameter(s) that are driving him nuts aren't standard and aren't specified. I'm sure a process engineer could provide us with a wealth of information but just try and talk to one. They are guarded closer then Roman Vestal Virgins.

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I'm going to check

Hfe at different collector currents, well away from the standard tests levels

Ft at different current collector currents

Actual switching speed at different collector currents

I'm trying to figure a practical way of measuring the collector base, base emitter, and collector emitter junction capacitance under different voltages.

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I once used a 2N???? as an electronic variable capacitor by using the collector base and reverse biasing, so I know transistor junction capacitance varies with applied voltage. I wonder if the audio can modulate the variable capactance of the junction [pretty certain it does] and "Does it have any effect?"

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I'm so far over my head I might drown.

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And a lot of audiophile "Standard of belief" is snake oil and smoke.

The idea a special power cable can improve an AC mains powered amp is silly, consider how many feet of house wiring is between the amp and breaker box, how long the cables from the home to the step down transformer, how many miles of wire between "your' transformer and the substation and how many miles of wire between substation and power plant, add to that the interconnectivity of the various national sub-grids....

? Double blind tests are the only subjective tests I accept. Others are entitled to their own beliefs.

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