Why Do I Hear Slight Artifacts With Expression to Volume?

You may notice slight digital artifacts (a soft zipper / stepping / grain) when using Expression to Volume, especially on very slow sweeps or with high gain / sensitive amp settings.

That behavior is a known limitation of the current Expression to Volume implementation. We’ve already tuned the firmware as far as we can on this hardware; further cleanup would need a hardware upgrade. It isn’t a fault with your expression pedal, cable, or UniPort assignment.

What helps

• Use a good TRS expression pedal on UniPort 1 or 2 with that UniPort set for expression / volume as documented.
• Faster, musical volume moves usually mask the artifact more than extremely slow fades.
• If noise continues when the pedal isn’t moving, treat that as a separate issue (power isolation, cabling, Constant Clock, etc.).

For setup, see Expression to Volume.