Help isolate hum

[Hiwatt5]

I built an 18 watt amp following the Trinity SIII layout, but with only 2 input jacks, with the normal and tmb channels internally linked with a wire across pins 2 and 7 of V1. If I keep the normal channel volume at 0, the TMB channel sounds great whether plugged into the lo or hi input jack. No hum.

When I start turning up the normal channel volume pot, I hear hum that gets louder as I turn the volume up, and the guitar signal sounds weak. It seems that this is a grounding issue. Could it be related to the input jack grounding or simply the normal channel volume pot?

[Hiwatt5]

Found my mistake. Didn't get the jumper wire soldered on pin 2.