Yes -Isolation. When there is the potential for an AC grounding issue. That was my main concern. About a potential for a ground problem. The speakers we are using are EV SX80+ They are will handle 175 rms continuous. They will but out 92 db with 1 watt in. The power amp we were using was located at the back of the auditorium. So the speaker wire was 80ft on the main and 100 ft. on the monitor. I would like to relocate the amp in the front of the room. That was why I asked about the quasi or Pseudo balanced input. Yes I do know about the differential input and the related op amps. Thanks for your thorough reply. Here is a link to an article at Rane Notes. I found it quite interesting. About the pin#1 problem. http://www.rane.com/pdf/whitlock.pdf I am sure you probably know all about this issue. That article got me to thinking about transformerless balanced inputs. Thanks again for your time.
I have been looking at the XLS Series and like the specs. We are a small church of less than 100. We have one main speaker, and one monitor, so its mono. We have 10 mic lines, a Mackie 1604 VLZ mixer. I am thinking of relocating the amp in front of the auditorium so the speaker lines would be a lot shorter. The speaker lines are #12 if I remember correctly. One of the features of the amp is the balanced input doesn't use a transformer. I know this is common in a lot of input that are supposed to be balanced. I believe the Mackie mixer doesn't use transformers either. I am looking at purchasing the XLS 202 as it looks like it will meet our needs. Any comments are welcome. You may e-mail me privately if you like. Lynn Blakely retired electronics tech.