vintage pritec tele-page pa system tube pre amp?



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

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!