Both my Bottlehead based home systems include vinyl playback, driven by an Eros and an integrated Reduction. I always read about systems describing "black background" with envy and some sense of failure. Both systems use short, decent cables and neither exhibit hum nor mains noise; but there is certainly not a black background. There is a difficult to describe low-level background hiss/buzz audible within about 6" of my speakers and in my headphones. It does not exist when using my solid-state phono preamp or a digital source.
As an experiment, a very expensive experiment, I built a respected board-based tube phono preamp. I built it "BH style" to drop into my systems, but with the PS in a separate, shielded enclosure.
Either I made the same mistake 3 times (actually 5 if you count the 2 rebuilds of my Reduction) or there is just some level of audible noise associated with all tube phono.
What is considered an acceptable level and how do I measure it?
The flip side is that it really doesn't detract from the fact that I think both systems sound d**n fine spinning vinyl!
Karl