I have a fully functioning tascam 238 and with my current mixer I can't have audio coming in from the machine and being monitored on the machine without feedback. To "solve" this I have the outputs of the machine routed into the inputs on my mixer and then pan the mixer channels I want to record from to the left and route the left of the main mix to the inputs on the 238 I want to record on and pan the rest of the channels hard right. I also have to unplug the input coming from the 238 on my mixer for the channels I'm recording on to to avoid feedback. It's a hassle to keep plugging and unplugging like this. Am I using my mixer wrong (a Mackie DFX-12), or would I have to purchase a new mixer in order to avoid this issue (I'm looking at Tascam M-1508s but there isn't a single listing with a power supply, or maybe a Tascam M-208 but those are really expensive and usually in poor condition). Any mixer recommendations would be appreciated.