Long ICs versus long speaker cables

As was indicated, opinions on this question will be divided, and there is no unequivocally correct answer. I would add the following to what has been said, though:

1)The higher the output impedance of your preamp, the more important it is to have low total capacitance in the interconnect cable. That means either having shorter length or lower capacitance per unit length, or both. Most preamps will have low enough output impedance that this will not be a concern with typical cables, for a 6 meter run, but that will not always be the case, especially with some tube preamps or with cables that have high capacitance per unit length. If it is a significant effect, the symptom would be upper treble rolloff.

If you wish, let us know what preamp you are using and I can calculate some specific numbers.

2)Assuming the interconnects are unbalanced, longer interconnects can increase the likelihood of ground loop hum and noise problems, due to the increased shield resistance that results from the longer length.

3)Having adequate wire gauge is obviously more critical for the speaker wires if they are longer, or resistance may increase to the point of affecting the bass.

4)Capacitance is, in itself, usually unimportant in speaker cables, because of the very low output impedance of the amplifier. For long cables, inductance may become significant enough to affect the upper treble. Lower speaker impedance at high frequencies increases the likelihood of that effect being significant.

5)Skin effect losses in speaker cables may have marginally significant effects on the upper treble, depending on the cable construction as well as the length. Lower speaker impedance at high frequencies increases the likelihood of that effect being significant.

6)I don't think that there is a clear answer as to whether the fact that larger currents flow through speaker cables, as compared to ic's, means that the various cable effects that fall under the heading of "unexplainable" will be greater or smaller. A case could probably be made either way.

FWIW, assuming your preamp does not have particularly high output impedance, my instinct would be to go with long ic's/short speaker cables.

Regards,
-- Al

Dpe,

Fortunately most of the Cardas cables have very low capacitance, with the Golden Cross at 25.5 pf/ft, and the Golden Reference at 12 pf/ft in single-ended form (and lower in each case in balanced form, but it looks like the LA-150 only has unbalanced outputs).

25pf/ft x 20 feet (slightly more than 6 meters) = 500 pf.

The capacitive reactance (impedance) of 500 pf at 20kHz is

1/(2 x pi x f x C) = 1/(2 x 3.14 x 20,000 x (500exp-12))
= 15,924 ohms.

That is very comfortably higher than both of the preamp's selectable output impedances. It can be expected that the 400 ohm and 1200 ohm output impedances will vary significantly with frequency, but I suspect that they would only rise significantly above those numbers at deep bass frequencies, where cable capacitance is unimportant.

So I think you will be fine as far as cable capacitance is concerned (with either of those cables), and just go with whichever output impedance sounds better.

Although keep in mind that if your power amp's input impedance is on the low side, meaning in the range of 10K to 30 or 40K or so, the 1200 ohm setting (which probably rises considerably above that number at very low frequencies) could result in some attenuation of the deep bass. That would occur regardless of cable length. If your power amp's input impedance approaches say 75K or 100K, then I'm sure the 1200 ohm setting would be fine in that respect.

As you may be aware, that is sometimes referred to as the 10X rule -- power amp input impedance should be at least ten times greater than the output impedance of the preamp at the frequency for which the output impedance of the preamp is highest, which is usually at 20Hz, especially in the case of a tube preamp.

Regards,
-- Al