Ampeg TRS input

[jessmann]

just bought a new ampeg svt8 and like on my old rig i want to rack mount all the gear i will be using . i am trying with this amp to run a input to the back of the amp so i can leave everything hooked up . i like my effects run into a channel not using a effects loop i think it just sounds better . can any one tell me why ampeg has chosen to use a trs input with 3 wires on it for an input .
wondering how that works given all guitar cables are ts. i did hook up a normal input and it did not work . any help in understanding this would help . thanks
Jess

[anderbass]

Don't push the TS plug all the way in, they'll usually work in a TRS input if only inserted until you feel the first detente.
(or if you cant feel that first detente: try pushing the plug all the way in, then pull it back out like a 1/4 inch)

[jessmann]

if you dont plug it in all the way no signal from the bass get to the amp

[Jerrold Tiers]

Ok this is the 8PRO?

The original 8PRO didn't have any input on the rear, so I assume this is the newest version? They must have changed it.......... except that the manual on-line is the same, and the unit looks unchanged externally.

So.... what and where is this "input" that you are using????????