Why is high capacitance good?

Thanks, Pani!

As you probably realize, there is no one right answer to your questions, because there are many system-dependent variables involved. And as you've probably seen, there have been lots of inconclusive debates on those questions, here and elsewhere. But following are some general guidelines, as I see it.

First, keep in mind that overall system synergy can sometimes be best served by cabling that functions in a non-neutral manner. But assuming that neutrality is the goal:

1)The likelihood that long interconnects will function in a neutral manner is increased if:

-- The interface is balanced (xlr's).
-- Cable capacitance is low.
-- The output impedance of the component driving the cable is low, particularly at high frequencies. (Having low output impedance at low and mid frequencies, as well as at high frequencies, can be important in relation to the input impedance of the destination component, but that is a separate issue).
-- The resistance of the cable shield (or other signal return connection) is low, particularly for rca cables. That is something that is not usually specified, but figures to have some degree of correlation with the overall quality of the cable.

2)The likelihood that long speaker cables will function in a neutral manner is increased if:

-- Resistance is low.
-- Inductance is low.
-- Speaker impedance is high.
-- The speaker is capable of sounding good with an amplifier that does not have a high damping factor. A speaker which is tube amp friendly will generally meet that criterion, irrespective of whether it is actually being used with a tube amp.

Best regards,
-- Al

Thanks for the world of info you have provided Al, very rarely do I come across such meticulously written technical posts.

Just one last question, could you please suggest what range of figures of Capacitance, Inductance and Resistance do you consider "low" for speaker cables and interconnects ?
I dont want to ask the manufacturer of my cables to answer these questions because he will try to always respond in a positive manner :).

Hi Pani,

What would be best, of course, is an analysis reflecting the particular component impedances, cable lengths, and cable parameters that are being considered. But that is probably impractical to cover here in a generally applicable way. And if you were to present your question about how low is low to ten different engineers, probably no two sets of numbers would be the same. But as a rough general ballpark I would say the following:

For interconnects, where capacitance is particularly important:

Low capacitance: Below 25 pf/ft (picofarads per foot)
Medium capacitance: 25 to 75 pf/ft
High capacitance: Above 75 pf/ft

For speaker cables, where resistance and inductance are particularly important:

Low resistance: Below 12 gauge (lower gauge = thicker)
Medium resistance: 12 to 16 gauge
High resistance: Above 16 gauge

See a wire gauge table, such as this one, to convert gauge to resistance, if necessary for analysis purposes.

Low inductance: Below 100 nH/ft-run (nanoHenries per foot-run, representing two feet of wire for the round-trip through both conductors)
Medium inductance: 100 to 500 nH/ft-run
High inductance: Above 500 nH/ft-run

Best regards,
-- Al

Thanks for the info Al.