I've noticed that tube preamps are also more sensitive to grounding issues and interconnect mechanical issues than solid state preamps. So you may try using a cheater plug on the preamps power cord to determine if you have a grounding issue and make sure that any locking RCA barrels are tightened.
Once I tried changing tubes several times and couldn't get my tube preamp to quiet down. Turns out all I had to do was to tighten the locking RCA jacks and the noise disappeared. It's worth the effort though, because tube preamps are more sensitive to the musical signal too.
If the noise still persists, then the preamp should be serviced.
Once I tried changing tubes several times and couldn't get my tube preamp to quiet down. Turns out all I had to do was to tighten the locking RCA jacks and the noise disappeared. It's worth the effort though, because tube preamps are more sensitive to the musical signal too.
If the noise still persists, then the preamp should be serviced.