More Questions about Tube Noise

If you will recall, perviously I posted a question about some noise form a pair of RT 12AU7 tubes in my CJ PV10A. (Thanks for the great info everyone, by the way.) I sent them back to the dealer and he found that one of the tubes was noisy and replaced both. I installed the replacements today but am still hearing noise of the tubes. Although, it is very faint and can't be heard unless my ear is within an inch of the speaker. The other tube is making no noise. So, my questions are: How much noise from a tube is acceptable? If a tube is noisy does that mean that it is 'bad' or not functioning optimally?

Thanks again!!!

Brad Day
Atlanta, GA