Musicians Roadhouse

Hey fellas,
My 2266C developed an annoying crackling sound which appeared about 5 minutes after powering up. It would go on for 10 to 15 mins sometimes.
I jiggled one of the KT66's with the amp on; and there was the crackle. I swapped the tubes around and problem gone. Sweet.
So it could be that the tube in question was just not seated properly. Do I need to put the tubes back in their original spots for biasing reasons?
And if the tube is in seated 99% in the slots; how can it not be seated properly? Bad electrical contact?
Can those bear claws actually work to push tubes out of their seats marginally?
Does anyone have experience of this?
Cheers.

My 2266C developed a rattle then a crackle. In that case it was that the glass part of the stock tube had become loose from the brown base. Until I found it the problem was intermittent and depended on how loud I was playing and which notes (some kind of resonance presumably). If it is a problem with seating the tube in its socket and the swap works, you would be ok with bias if the pair was a matched pair and you don't bias too hot. I had a tube red-plate in a second hand 2266H because I hadn't checked the bias (doh!), so better be safe than sorry and check it when you can.
I have used the stock Marshall tubes, Harma KT66s and Gold Lions. The Gold Lions have never rattled or come loose in the Combo and sound the best to my ears. I also use a little electrical contact spray on the pins when I change tubes.

Thanks.
They're Gold Lions and I have always had rattle with them. Maybe the rattling has caused tube damage in one.
I will try the contact cleaner thing too.
I have a new pair of Valve Arts 66's to try out if the problem continues.

I had the same problem with the stock tubes in my 2266c. The glass was loose in the plastic base of the tubes. After changing tubes for Tungsol. 6L6GC STR no problems and great tone!


Dana's blues

I replaced the tubes and also the bear claws with spring retainers.
No problems at all now. Not sure which swap fixed the problem, but the old tubes were rattling pretty bad and that has all gone too.
So its possible the glass had come away from the base of the tube. Just overall tube disintegration?
Sold on these Valve Arts at the mo!
Cheers :