40 feet balanced between preamp and Levinson....

If you using ML you should deffenetely go for Transparent Audio or MIT. They are best working in long length.

I agree with Sean on this - LAT will be able to help you with a quality cable and good/fair price - I use them.

Go to the local electronic parts house and have them make up a pair. Bet it's a lot less than $800 (used!). According to the manufacturer of my Atma-Sphere pre-amp, it can drive lengths as long as 200 feet. Don't know about the Audio Research. You could ask 'em I bet.

It is my understanding that the folks at Atmosphere are using runs of balanced Belden cable between their top end preamp and power amps. Would be worth a call to Atmosphere to find out what they have to say about it. I'm sure they are able to use whatever they want. One of the advantages of balanced cable is they are suitable for very long runs and they are said to have much less of a sonic signature than single ended cables. Just a thought and it would not cost very much to find out. Given that Belden caters to a different market there is no hype or the snake oil so often present in the world of high end audio cables. Good luck with it.

I used to have 33ft between ML380S and ML336 (recently replaced with Halcro) I am very pleased with Stealths CWS balanced cables, they were customized to offer low inductance (helps performance at long lengths (return/ground path must have low inductance in order to provide 'transparent" ground link at all frequencies (not only low ones )according to Stealth)
Matt