I just picked up a pair of Jan Philips 6L6WGB from the tubestore. I wasn't expecting a change in tone and wasn't sure I even needed to replace the JJ tubes that were in there. However I didn't have a set of backup power tubes so I figured why not. After the change I found I had noticeably more volume and clean headroom. The bass seemed tighter. Overall a tone improvement. So I'm wondering if the JJ tubes that were in there may have been worn. Or there could be another reason that it sounds better. Full details: Amp: Allen Accomplice. Recommend Bias range: 30-35MA I decided to check the bias on the old tubes first before I took them out. After about a 20 minute warm up I found them idling at 29-30ma. I could have sworn when I biased a couple months ago that I was closer to the "Allen" recommended maximum of 35MA. Lately I've been getting a bit of an ugly tone mainly in the mids. Wondering if it was because I had this biased on the cold side. So then I put in the NOS tubes and biased to 34-35 MA (Just about exactly the pair were within 1MA or slightly less of each other). I let them amp warm up for 20 minutes. I then plugged in and noticed the improvement. So was it because the new tubes were fresh and the old ones possibly worn out or because I biased it warmer? Is 5ma warmer that much of a difference?