Myles,
I am using an old Knight phono amplifier to run my archtop through. I had the input modified to accomodate a 1/4" jack and the output wired for 8 ohms. It has two RCA black plate 6L6 output tubes.
I began using this amp about a year ago and it has always had a very nice clean tone. (I use it with mainly wit my Guild X150.) However, volume wise, I could turn it up to 10 and I'd guess it wasn't putting out over 2 or 3 watts, even though it says 20 watts. In addition, it never clipped at full volume, but I guess that's by design.
Lately, the volume has dropped to about half of what I was originally getting. For a while it would get back up to its 2 or 3 watts after warming up for 30 minutes or so, but not any longer. My question is does this sound like a tube issue, i.e., is a loss of volume associated with tubes going bad?
Sorry for the long post.
Thanks in advance.