18 watt TMB squeal & hum

[JMPGuitars]

The Speaker Jacks are grounded, I didn't identify them in the pic.

Normal practice is to connect the OT negative lead directly to the output jack, and then run a ground wire back to the star ground. The black lead from the OT is not ground (it's the negative lead going to the speaker negative terminal), but the jacks should be grounded.

[MSVguitar]

Normal practice is to connect the OT negative lead directly to the output jack, and then run a ground wire back to the star ground. The black lead from the OT is not ground (it's the negative lead going to the speaker negative terminal), but the jacks should be grounded.

Thanks Josh, I will make the change to the OT and Speaker Jacks.
Mark