got the pedal back, builder was very helpful in fact.
the tone pot is changed so it gives a much more usable sweep.
the volume control still gives a fuzzy tone with certain guitars. by far the worst is my hamer with aftermaths, but some others do it a touch too.
i feel sure this is because of bass frequencies on the pedal input.
as i say, the problem also affects my klon, but not my sd-1 or od-1
i wonder if it would make sense to include an input parametric shelf filter on high end pedals to adjust low-end cut <- answers on a postcard.
generally i have found with clean boosts that the boost only works so far and then things fall apart unless you do some frequency tweaking. thats why i like to use EQ pedals as a clean boost.
overall, klon vs od820, i have to say i like them both alot. the drive seems to sound a bit different. i know people say the 820 is better than the klon, but i couldn't honestly agree with that. both are excellent, i'm pleased i have both.