The ring on the plug (which is hooked up to one of the ends TS ends) will not make contact with anything in the jack, so one of the two "outputs" will have no signal (it will, in fact, be an open, which is pretty bad for the amp). You need to either move the wire on the Ring connector to the tip connector, or replace the TRS plug with a TS plug.
Also, if you have active electronics (or at least, with MOST active electronics, there are other ways of switching them), if you have a TRS plug the electronics will not be turned on, because the circuit is completed by the sleeve of the plug making contact with both the sleeve AND the ring of the jack. The negative side of the battery is hooked up to the ring of the jack, and so the sleeve of the plug completes the battery's connection to ground.
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