is there any way to reduce buzz from master volume knob on marshall code 25? the difference between level 1 and 2 is tremendeus,  beside ist get a little crackly while turning knob from 0 to 2 or 3 (7-8-9 o'clock)

Hi everyone!

Recently I bought Marshall CODE 25 and it's a great amp but I have one little problem with it.

There is a problem with MASTER potentiometer. I noticed that when I set it between 0-0.99 it is very very quiet but when I set it about 1.0 it becomes very loud. And in the effect it is very hard to play at "bedroom" volume levels. I must say that I'm disappointed - I had Yamaha THR 10 previously and it could play very well at every volume and it could play very quiet.

So to sum it up, is this some general issue with all CODE amps or something is broken in mine? Maybe master potentiometer needs repair?