Tube preamp noise question

I have a question for experienced tube preamp users. I purchased my first tube component, a preamp, a few months ago and am having a noise issue. It uses 5881 and 6SN7 tubes for their respective functions. I have not yet contacted the manufacturer because I wanted to sort out the issue myself if possible. The noise I hear is somewhat like the crackle and pop of a scratched LP. Sometimes, it could also be described as like the “roar” of a natural/propane gas flame (e.g. Bunsen burner), and sometimes it sounds like “squeaking” of Styrofoam rubbing, etc. It comes and goes and does not seem to go away as the tubes warm up. At first it was only in my left channel so I swapped the tubes from L to R but the noise remained in the L channel. My thinking at that point was that it wasn’t tube related and must be something in the electronics of the pre. After a month or so, now the same of noise is appearing in the right channel as well. The noise is not subtle and can easily be heard while music or a movie is playing. It’s embarrassing when having friend over as well.

My question is what may be causing this? My speakers are sensitive (95 db/w) so not sure this could just be tube rush because of the volume and intermittent nature, but I'm not familiar with tubes enough to rule that out. Is it a case of noisy tubes that I can replace or should I be concerned about the innards of the component? I appreciate any insight and thoughts you may have.