Tubes and their problems

Atmasphere, thank you for your in depth answer. I was hoping that you could explain arc-over and its cause.

Daveyf,

I wouldn't presume to offer a tech answer when the likes of Ralph (Atmasphere) provides such comprehensive advice. That said, being a fellow "tube-o-phile," I would only mention that many manufacturers suggest that tubes be replaced within a certain life span. I surmise that tubes are more susceptible to failure or performance degradation if use exceeds recommended replacement points (as measured in hours in service).

In my case, ARC recommends that 6H30 signal tubes be replaced at the 4000 hour point. I understand that the new KT-150 power tube has a 3000+ hours life span.

I'm sure every manufacturer has its own recommended re-tube specs. Ralph, what do you recommend for your amps??

Bifwynne, of course, let us pray!

Actually the tubes that are making the noise are ( I think ) in my preamp. One of them lets me listen to the Al-Jareera radio station when the gain is turned up! Interestingly, they are not that old, probably have only a few hundred hours on them, if that. Nonetheless, I am happy that they are in the preamp vs. the ARC amp. My ARC D70mk2 amp is a bear to re-bias if it needs tube replacement.

Daveyf, lets hope the bad tubes if any are in the preamp. I think you have some concerns but more importantly you are picking up a station I've never heard of.