40ft: speaker cable or interconnect?

The Blue Jeans Cable LC-1 is what I chose because of the same situation. Plain vanilla, but I wanted a shielded cable due to running it very near other interconnects, AC lines and outlets. The cost for 40 foot pair is $110 plus shipping. I placed the amps right next to the speakers and used short speaker cables. It worked for me. If it doesn't suit you, you can return them in 30 days for a full refund. Have fun experimenting!

http://www.bluejeanscable.com/store/audio/index.htm

John, one thing to keep in mind is the output impedance of your preamp and the input impedance of the amp. I was in the same situation as you last year, and discovered to my dismay that my old amp's input stage oscillated uncontrolably with long ICs. I don't think this will happen with the Bryston, but you may want to call both Bryston and your pre's manufacturer to see if there are any recommendations in this scenario.

I tired last night to get a balanced connector through the flexible conduit but it won't fit. Unbalanced works fine. I don't want to push the wire through and then put a connector on after it passes through. That means I'd need to use unbalanced or speaker level.

Sounds like some thought unbalanced over this long a run is no better than speaker cable. Does that sound like the general consensus?

I recommend balanced interconnects when using long runs. Single ended ones suffer from high frequency roll-off and also can be much more susceptible to noise, which are significant reasons why balanced connections used exclusively in professional applications.

John, long single ended *is* possible. I solved the problem I was having (described above) by moving to a new amp (which I was coincidentally looking to do anyway). My new amp is an AVA FetValve, which has a very high (and stable) input imdedance and makes for an easy load to drive with long ICs. The AVA only has RCA in, so I tried a few things and went with well shielded RCA ICs (Purist Venustas) that are 30 ft long. I compared them to what I was using in my old arrangement (Kimber KCAG at 1.5m) and discovered no discernable rolloff or ill effects in using the Purist cables. The resulting combination works very well for me. YMMV, and I would suggest being very careful to assess all parts of the system in trying to find out if this might work with your equipment - even to where the cables will be routed relative to other sources of potential interference. But it can work.