Why don't you just try some solid copper from HD as I suggested. I'm not recommending it as a permanent solution; but it will tell you right away if that (speaker cables) is the problem. Another thing you want to double check is your amplifier taps -- I'm assuming you're aware that when you bridge the 275's into mono, the impedance designation printed on the amp for each speaker tap is no longer valid and you have to go up a tap (i.e., an 8 ohm speaker should be hooked up to the 16 ohm tap.) Check the owners manual.
As for cables other than the Kimber, there's a pair of one of the all-time great workhorse speaker cables (Straightwire Maestro) available used (always buy speaker cable used ;--) on the Gon right now, for no money, in just the length you need: http://www.audiogon.com/cgi-bin/cls.pl?cablspkr&1273259411&/Straight-Wire-Maestro-SpeakerThere are also a couple pairs of Virtuosos, a later design, for a little more money:
http://www.audiogon.com/cgi-bin/cls.pl?cablspkr&1274549629&/Straightwire-Virtuoso-Speaker-
I used both models for years (the Maestros for 10 years) and they are one of those sleeper products that are very hard to beat (especially for the used price!)
If you want to spend some bucks, a pair of mid-priced Virtual Dynamics. Most VD speaker cables come as two separate cables per speaker (a plus run and a minus run) with solid conductors. This completely eliminates capacitance and inductance. If you want to spend a lot of bucks, Purist Venustas or Provectus (the Provectus is solid core two runs like the VD) but you're probably talking $1200+, even used.
As for cables other than the Kimber, there's a pair of one of the all-time great workhorse speaker cables (Straightwire Maestro) available used (always buy speaker cable used ;--) on the Gon right now, for no money, in just the length you need: http://www.audiogon.com/cgi-bin/cls.pl?cablspkr&1273259411&/Straight-Wire-Maestro-SpeakerThere are also a couple pairs of Virtuosos, a later design, for a little more money:
http://www.audiogon.com/cgi-bin/cls.pl?cablspkr&1274549629&/Straightwire-Virtuoso-Speaker-
I used both models for years (the Maestros for 10 years) and they are one of those sleeper products that are very hard to beat (especially for the used price!)
If you want to spend some bucks, a pair of mid-priced Virtual Dynamics. Most VD speaker cables come as two separate cables per speaker (a plus run and a minus run) with solid conductors. This completely eliminates capacitance and inductance. If you want to spend a lot of bucks, Purist Venustas or Provectus (the Provectus is solid core two runs like the VD) but you're probably talking $1200+, even used.