So i have two 27 band (odd?) urei 539s. They have terminal blocks on the back, however there are also 1/4" jacks. The manual i found doesn't indicate they have them so i'm thinking it was a custom job. So i hooked them up with unbalances TS cables and they wouldn't process, they just passed the audio through. Could it be that i must use TRS? Or is it that i just have to cut and strip some TRS cables and assume the custom job was no good?