Arny Krueger wrote:

A 50 foot cable with RCA's at both ends.

Usually off-the-shelf cables are only 20 or 25 feet long, but standard cable
joiners work, tape 'em up if they tend to pull apart.

As Mike suggests, you might have to pay attention to how you route the cable
to avoid picking up hum.

If you can get away with plain wire in an application like this, it will
probably sound better than transformers unless you drop big bucks on the
transformers.

Thanks, Arny. If it ends up being much of a problem, I'll just use my
Mackie (which means more hauling stuff around). But it will be cool if
the RCA does the job adequately.