I just finished building my first truepath. After some sticky muting issues it actually worked! At least almost
2nd channel seems to work, but the coil of the 1st channel heats up quite quickly. Almost too hot to be touched after a minute when no input or load. I have tested it briefly with some audio input with a speaker connected and it actually seems to work, but coil keeps heating intolerably hot.
I have tried to track the problem without success. The 2nd channel doesn't have any issues, but I can't find any differences i.e. when comparing voltages and resistances between the 1nd and 2nd channels.
My strongest theory would be that there is an strong high frequency AC voltage in FB1 net (which my multimeter can't measure). Otherwise there can't be current flowing trough the coil. There reason could be the feedback circuit (FBKOUT1/FBKGND1) but there is not any anomalies there either.
I have only a multimeter (no oscilloscope) to test with. 2nd channel has about 80mVac on its output on idle and so has the 1st channel. Is it normal? Has anyone else had a similar problem?