It's an excellent combo,I primarily make silver speaker cables, but all my interconnect's are copper.Silver is the lowest resistance metal,so it would work best as speaker cable because of the lower resistance involved.The low level signal's of interconnects dont benefit from the lower resistance of silver like speaker cables do.That's not to say silver isn't good for interconnect's because it really is,but if I where to mix and match I would use silver speaker cable with copper interconnect's.
