40ft: speaker cable or interconnect?

This comes up pretty regularly here at Audiogon. I have seen posts answering both ways.

In my opinion you are better off with low loss interconnect as that signal fairs well in long runs, compared to high power through speaker wire. A good example of long interconnect is microphone cables in recording studio's, 100 feet and longer is not uncommon.

Too, long interconnect is much cheaper than equal length of speaker if your using any popular name brand cables found here at Audiogon. Personally I run nearly 40 foot runs of interconnect in my own system with short speaker and my performance is excellent.

My results are identical to Tonyptony. I have nearly 40 foot runs between my tube preamp and amps. The amps are VTL 750 (single ended design) so I use RCA connectors at both ends.

Just because an amp has XLR connectors does NOT mean it's balanced.

Many amps have both types of input jack but pulling the cover you discover there are jumpers running from the XLR over to the RCA.

At that point it's merely a convenience jack, providing a place for the owner to use an existing cable. There is no gain to be had wiring the circuit this way, unless you just happen to prefer the XLR connector over the RCA design.

The trick to maintaining performance is choosing LOW IMPEDANCE, low loss interconnect cables. The reason Tony had positive results, the Venustas he choose are approximately 17 pf per meter, meaning a 50 foot single ended run represents a capacitive load of only 250 pf.

I don't have the charts or specs for the input impedance of your amp/preamp, but I'll bet roll off would not occur until about 300,000 kHz. That’s far beyond the range of doing harm to music bandwidth and should provide you with the lesser of the two evils of running signal over a long path.

Whatever brand of cable you choose, be sure the impedance of your amp/preamp interface COMBINED with the total pf capacitance of the cable run do not represent a bandwidth problem. Most engineers understand this, you might call an impartial party such as the maker of your amps for specs and advice for maximum load that can be placed on your equipment.