I have a custom EQ setting set and saved in slot two. If I switch to the default EQ setting #1 a loud pop is heard from the system.
Know what you mean: mine does the same, or rather it makes a 'knack' sound; not a pop

Similarities:
My custom EQ is also in slot-2

Difference:
It 'knacks' when switching to EQ3 (haven't tried to switch to EQ-1), but only the first time 'round. When I keep cycling the EQs, next time when it changes from 2 to 3 it is quiet

And my dimmer does not work when the head lights are turned on. The lead is connected.
Check the voltage on the feeler wires. Head lights on dims my Mk2 without problems
(is the dimmer option for 'lights-on' to less than 100%?)

Henno
mk2 6 nr 6