"This amp came in for a good service because, although the amp was working, the owner was concerned at the amount of "popping noises and kettle sounds" that were coming from it. I changed all the components, except for one wire wound resistor (these are usually ok), and believe it or not the main smoothing capacitor was still perfect! All 3 original Mullard tubes were fine too (including the EF86........uhh, not one of my favourite valves!!).
After its service, the little amp sounded great. She is as good (actually better) now than when she was new. Not a blemish of noise anywhere.