You could always use round white/or brown? junction boxes fitted with
threaded compression terminals with gaps for securing thick wires. Cheap.
Some are 4-, 5- or 6-way, with a screw cover and knock-out entries,
available in both 1.5mm2 or 2.5mm2 flavours.
Most electrics trade shops sell loads of these, usually for hiding above
ceilings and in lofts.

wrote in message
ups.com...
Thanks, Nick.

I _am_ intending to use binding posts at both ends. I just thought it
would be aesthetically neater at the amplifier end to have a wall
plate, with the binding posts protruding from the wall plate.

Perhaps, I need a bigger soldering iron (my electronics iron may not be
meaty enough to heat up heavy gauge copper).

I would still prefer to screw the cable to the back of the plate,
rather than solder it though.