Having a bit of a change around during the hols, and I need to link up a
computer (Mac Mini) to a USB DAC 5 metres away. I've tried it with a 5m
extension plus a 1m A-B cable, and it works, but the music cuts out from
time to time. Actually, seems fine for the last few hours, but I need an
extension cable anyway.

I would just buy a 5m cable and be done, but ebay sellers are pushing
something called 'active repeater extension cables' for about 5 quid
extra. I can't seem to find anything about them - should I spend the
extra five quid on such a thing?

Unrelated, I've just noticed that I can change the volume of the music
using an iPod Touch remote application through the Mac - on the optical
output and the USB. How does this work with digital?!

Thanks, Rob