there's an error on the
schematic I have,  I just noticed I didn't correct it in the new schematic
from the chan 2,3 schematic there's a wire that goes from the first tube's
anode to the clean channel.   There's no coupling cap, and there most
certainly has to be one.  I don't know what the original cap is,  22n should
work fine.

there's only one line outside the drawing  it goes from the coupling cap to
the switch.   The values of the tone-pots are 250k