reverb problems on a Mark I

[guy_incognito]

So I've got an original Mark I, and a while ago, the reverb started making this horrible distorted sound at any volume. I took it into the shop to see what was the matter with it and get it fixed, and I was told one of the tubes was microphonic, which he replaced and the problem seemed to be solved. But, now, it's doing it again; not all the time, but only when the amp is on the louder side. I can crank it with the reverb turned all the way down with no problems at all, but once you start putting the 'verb into the mix, it starts to crack up and sound awful at higher volumes. None of the tubes look like they have anything wrong with them, to my untrained eye, but they have been in there for a few years now...

So, should I probably just replace the rest of the tubes, or might there be another problem at work here?

 

[Boogiebabies]

:roll: