i found this vintage single channel pa system in a second hand store... i want to use the preamp to see if it sounds any good for recording. The tubes seem to be in good condition they look pretty new so i dont think theyt are original. 10 bucks so i said why not.... It has an xlr input but the outputs to the speakers is a weird 8 pin connector, its got like 8 xlr pins in a circle, ive never seen this before? I soldered an unbalanced 1/4 cable to the other end and tried to run it in to my mbox via line input, it worked but it sounded like a ground loop, i got shocked also... the power chord has a grownded power chord.... was wondering in anyone had any thoughts and if anyone can answer these questions that would be great 1. what is the 8 pin circle connector called and is it poosible to buy/build a balanced connection from that to 1/4 inch? 2. How can i get rid of the ground hum? 3. Has anyone heard of these units before? thanks alot marc ps. it works through the speakers that came with it but they sound like $*^t so i still cant tell what the pre sounds like!