Long Speaker Cables/Short Interconnect or reverse


I'm considering re cabling my system and have a question regarding the desirability of using of long speaker cables with a short interconnect, as opposed to shorter speaker cables with a long interconnect. I currently run a 21 foot pair of speaker cables from my equipment stand to my speakers, and a one meter interconnect between my pre and power amp. I could move my power amp closer to the speakers which would allow me to use a 11 to 12 foot pair of speaker cables, however would necessitate about a 11 foot interconnect. My preamp is an Audible Illusions L3 which does not use a cathode follower and has a relatively high (1.2Kohm) output impedance, however they claim a longer interconnect can be incorporated as long as it is of a low capacitance type. It is a single ended pre so a balanced interconnect is not possible. So is it advantageous to cut the speaker cable length by 10 feet or so if the interconnect is lengthened by 2+ meters? My speakers are specified as 8 ohm nominal, 6 ohm minimum (I read a post by the technically well versed Almarg who stated that allowable cable length is dependent on speaker impedance), and my amp is solid state with an input impedance of 50K ohms. Although logistically trickier, I could also possibly move both the preamp and power amp closer to the speakers, and run the longer interconnect from my cd player (RA Opus 21 with an output impedance of a low 100 ohms) which would need to physically stay where it is
Thanks in advance for all your advice...
weebeesdad

Showing 3 responses by almarg

Weebeesdad, thanks for the nice words. And thanks for providing the relevant specifics in your post.

I'll mention first that I suspect that the actual output impedance of your preamp is somewhat higher than the specified 1.2K. The output impedance of the Audible Illusions Modulus 3A was identically spec'd at 1.2K, but was measured by Stereophile at close to 1.8K.

That said, if you use a very low capacitance cable such as the Blue Jeans LC-1 (12.2 pf/foot) that was suggested by Czarivey, you should be ok with an 11 foot length as far as the most predictable adverse effects are concerned, namely the possibilities of high frequency rolloff and phase shifts. But as Stereo5 alluded to, a relatively long length such as that might increase susceptibility to less predictable length-dependent effects such as ground loop-related hum or noise. And the same possibility cannot be ruled out in the case of the CD player, despite its low output impedance.

So although as you've probably seen in my posts in past threads on this question I tend in general to be biased somewhat in the direction of long interconnects/short speaker cables, in this case, given also the impedance of your speakers, my instinct (assuming you are happy with the sound quality you presently have) would be to leave well enough alone. Or if you do want to experiment, the Blue Jeans cable is fairly inexpensive, even at an 11 foot length, so there would be little risk in giving it a try.

In saying this I'm assuming that the speaker cables are heavy gauge (i.e., gauge number not higher than 14), and have reasonably low inductance (say less than around 0.15 uH/foot or thereabouts). If you're not certain about those parameters, let us know the make and model of the speaker cables.

Best regards,
-- Al
Brad, to the limited extent that speaker cable performance can be predicted based on technical parameters, with resistance and inductance usually being the most important ones, biwire Signal Cable Silver Resolution is an excellent choice for a 21 foot run, given the impedance characteristics of your speakers. I'm less certain about the Clear Day Double Shotgun cables, even at 11 or 12 feet.

In saying this I'm assuming that the goal is for the cables to have as little effect on the signal as possible, as opposed to acting as tone controls to some degree.

I've been puzzled by the technical descriptions provided at Paul's website. It indicates that the conductors are 24 gauge solid core silver, with the double shotgun version using 4 conductors for + and 4 conductors for -. In silver that would equate to a little heavier than 18 gauge for each conductor (closer to 18 than 17). Yet a separate indication is provided, apparently referring to a single pair of conductors, which states "resistance = 0.00325 Ohms/foot run." That corresponds to a much heavier gauge than even that double shotgun equivalent, and one which I would not expect to be achievable in pure silver at anything close to the prices Paul offers.
Al, however I'm guessing that for the long length you would suggest running two pairs for the biwire as opposed to one pair and jumpers (would this effectively lower the gauge?).
What would lower the gauge more effectively would be to run two pairs in parallel, in other words, with the jumpers in place. Although since biwiring is alleged to often provide other benefits, it might be worth trying it both ways, with and without the jumpers, using a variety of recordings.

Regarding the JPS cables, I don't see enough technical information at their site to comment. Regarding compatibility if and when you change to a tube amp, perhaps all that can be said is that the more closely the cable approaches behaving in a neutral/accurate manner in combination with your present amp and speakers, the more closely it will do so with the tube amp.

The bottom line, IMO: While you may or may not find the Clear Day cables to be subjectively preferable to the present Signal Cables, if neutral/accurate behavior of a long length is the goal I would have a higher degree of confidence in Signal Cable. Given, as I said earlier, that the predictability of all of this is of course limited.

IMO. Best regards,
-- Al
Hi Kijanki,

I believe that what I said is correct. According to this wire gauge table the diameter of 14 gauge copper wire is 1.63 mm. Plugging that into this inductance calculator, together with a length of 12 inches, results in an inductance figure for a physically isolated single conductor of 358 nH, or 0.358 uH.

Signal Cable Silver Resolution is spec'd as having an inductance of 0.13 uH/foot, presumably reflecting the combined inductance of the two conductors, which are described as having a twisted and "cross-linked" geometry.

Clear Day is described as having an inductance of 0.30 uH/foot run.

Certainly there are many audiophile-oriented cables having inductances that are way lower than both of those figures. But 0.13 uH/foot, and perhaps even 0.30 uH/foot, would represent low enough impedances at frequencies of interest, at a 21 foot length, to be insignificant in relation to the impedance of Brad's speakers. Even more so considering that the impedance of most dynamic speakers (which I presume are what he has, based on the impedances that were indicated) tends to rise at upper treble frequencies and beyond.

Best regards,
-- Al