XLR & 1/4" combo jack wiring question

Hi!

I am confused. I built a bass preamp with both 1/4" and XLR output jacks, and I also built a power amp to go with it. Initially, I just used a standard TS 1/4" cable to connect them, and that works just fine.

When making some otherwise cosmetic changes to the amp, I decided to install a combination XLR/1/4" jack to take the place of the single 1/4" input jack. I wanted to do that to keep noise to a minimum.

Here comes the question. the amp board input only takes an unbalanced (hot and ground) input so I wired the jack so that the hot wire goes to the T connection and the shield/ground wire goes to the S connection on the jack, and that works just fine for the regular 1/4" TS cable.

What wires do I connect together so that, if I am using an XLR cable, it will work properly?

It would seem to me that I should run the wire from the T connection to BOTH pins 2 and 3 and the wire from the S connection to pin 1. Is that correct? If not, please correct me.

Thanks in advance for your assistance.