Ok, thanks for your reply, that sounds like a risk I'd rather not try out then.
It seems pretty much impossible to find an amplifier switch box over here (The Netherlands). Only speaker switch boxes, and the manufacturers (I e-mailed them) all say their devices can't be used reversed (but none could tell me why...).
So after your reply and some search I found out, it should be easy to create myself (something like this
Now I just wonder if there should be a specific maximum ampere the DPDT (2x) or 4PDT (1x) switch(es) would be able to handle?Edit:
Or a way to calculate that?
I used 2x DPDT switch of 10A. Works excellent and I can't hear any differences in sound quality.