The one here tracks very poorly at low volumes.
You'd have to source a similar value stereo volume control pot and replace it. It might be possible to disassemble and rehab the pots, but I wouldn't tackle it myself (the odds of the pots' survival would be low indeed were I to try surgery on them).
Looks like the volume control pots are 1 meg audio taper -- if I am reading the Pioneer SX-34(B) schematic correctly.
(obviously at least one non-stock knob on mine :) )
all the best,
mrh
