Geofex Hummfree A/B/Y noise problem

[served]

Hi.

I built the Hummfree A/B/Y from geofex and generalguitargadgets. http://generalguitargadgets.com/projects/15-boostersrouters/16-amp-aby-switcher-box

I used shielded cable from input jack to board. I used shielded cable from board to two putputs. Jacks are isolated (plastic).
But I am experiencing some really weird humms and problems.
Even with only one amp and clean, I am getting humm and noise.
If I disconnect the input cable I will get crazy noise. If I switch from one amp to other the first one will stay making noise.

Is this normal?

I have thought about the problem. I think that nothing grounds the outputs when they are unselected, and this is why it makes bad things

[trixdropd]

You need to have the 1st output connected to ground. Then the noise will go away. Just run a wire from the ground input of the transformer to the ground of the output jack, and make sure the enclosure is grounded as well.
No matter how many outputs you use, you will need at least 1 with a solid connection to ground.