In Reply to: Interesting cable problem, need ideas posted by morrowaudio on May 8, 2008 at 04:19:21:
Howdy
You might try propheads (if you haven’t already) or directly email inmate jneutron (http://cgi.audioasylum.com/cgi/mail.mpl?user_ID=15149). He’s great with the math.
My gut guess is that you are running into an amp like some Naims which can’t deal with too much capacitance without problems. Some amps (notoriously early SS amps) use a lot of negative feedback weren't designed well enough when the phase angle goes too far towards the capacitive instead of the inductive. (I.e. when the freq reaches the point that thru a fixed delay (the feedback loop time) that signal is in phase rather than out of phase…) For a more accurate description you might want to read http://en.wikipedia.org/wiki/Negative_feedback_amplifier and in particular http://en.wikipedia.org/wiki/Bode_plot#Gain_margin_and_phase_margin
Put more simply, I believe your first recipe is has too much capacitance for some amps (tho I guess I'm surprised that you are running into amps that are this sensitive.)
There are also posts around the place that talk about the trade offs between capacitance and inductance in various cable geometries.
-Ted
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Follow Ups
- Too much capacitance? - Ted Smith 15:43:40 05/09/08 (1)
- I agree - Russ57 07:58:09 05/12/08 (0)