I am trying to hook up my efx 500 to my ttm75 sl, I am having a sound issue when i activate the efx unit, the result is that the sound is audible on the left channel only, i am using dual 1/4" one tip connector. Should i be using the 2 ring tip connector...What's the difference between TS or TRS?

You don't need balanced cables for that short run - just TS is fine.

Have you got all 4 cables hooked up properly?

I believe everything is hooked up properly. I will try replacing the cables with another set and see what happens. The EFX unit works fine with any other mixer using the rca cables, but once I go to the ttm57 with 1/4" I hear the problem....might be a rane issue...I will double check and post back later on...

I tried it last night, mixed for a good hour and a half using the EFX and no problems at all with the sound. I also tried the old cables and the problem came back....thanks for your input Pulse!

Aha - so bad cables were the culprit!