Im having some troubles getting my 4-track to record with my amp plugged into it (gotta be able to hear what im playing). Its an AMR 64, MCR 4, real old I think, my uncle gave me it. On the right side of the 4track theres 4 input jacks, but I dont use those, they dont record for some reason... Then on the left side theres sets of [buttons for volume and equilizer stuff, switches, and a "Line" and "Insert" jack]. There are 4 of those sets 1-4 then a divider and a 5th and 6th set. I am using the "Line" jack to plug my bass in on the first set then my friend is also using one of the sets with a guitar in the "Line" jack. We can record and it works great, but we can only hear ourselves through the stereo jack. The problem with that is that the guitar and the bass run are coming out my bass amp, because thats what I put in the stereo jack. Thats not good plus we each wanna use our own amp. So next to the 'line' jack is am 'insert' jack. When we plug our amps into the corresponding insert jacks, we can hear ourselves. Great right? Well now when we record it doesnt actually record what we play on our instruments, it just records a constant humming noise. Im not sure what to do though, any suggestions are appreciated. Thanks so much!