I have a Boss GT-1 guitar pedal. I can't get a good monitor while I'm on stage so I'm thing of buying a decent amp and I'm thinking about buying the new JC-40 amp. Can I listen to this amp from its speakers on stage while the line out is being used by the PA system? Thanks.
You can do this with any amp that has a line out. Line out isn't like a headphone port, which usually switches out the internal speaker, but an output from the pre=amp to go to another amp - or in your case, a p.a. system.