making progress on mosfet booster hiss...

[rpjones]

As per suggestions from the good people of this BB I made an audio probe and have "isolated" the hiss from my AMZ mosfet booster. if I probe the drain resistor, I have no hiss on the +9V end of the resistor, but it is there on the transistor side of the resistor. It is the resistor directly below the trimmer in this picture.

You can see the schematic on the AMZ website, the mosfet booster. I have also discovered that if I ground the left end of the resistor in the lower left hand corner, which is the input resistor between the poly cap and the mica cap, it grounds out the hiss, but it is still there if I ground the poly cap before the resistor. Does this give anyone any ideas on a possible source of the problem? Regards and thanks, so much knowledge out there!