I just spun two new records (both 180g vinyl) -- Rickie Lee Jones, Rickie Lee Jones and Pop Pop. Interesting result when I swapped out Bugle Boy and JJ 12ax7's.
Background: I recently won a Denessen Soundtracktor on ebay and decided to align my cartridge with it. I had used the Alphason protractor that came with my HRS-100, originally. I was using some new JJ 12ax7's that I got for cheap and noticed they didn't sound half-bad after breaking in. When I aligned my cartridge with the Denessen, I noticed that voices opened up, there was more air, and the soundstage generally cleaned up, but the bass was so thin that I really thought I had better start researching good sub-woofers.
Tonight when I received these two records and spun them I thought I would put the Bugle Boys back in the pre-amp. Of course I listened with the JJ's in at first.
Well, with the Bugle Boys I immediately realized that I don't need a sub-woofer in my current set-up and room. It was such an amazing contrast! Truly immediate and night-and-day. I know that JJ's are basicaly run of the mill 12ax7's, but I never would have guessed nor imagined that the difference would have been so dramatic. I am truly glad that I have 3 matched pair of the Bugle Boys! It will be a long time before I need to use the JJ's.
Besides the incredible difference in bass, I also noticed timbral, soundstage depth and width, mid-range, and high frequency improvements that were significant. On the high end, I noticed a raspiness or edge with the JJ's that disappeared with the Bugle Boys. I thought that the records, being re-mastered were perhaps badly pressed. The edge and rasp disappeared with the Bugle Boys.
My conclusion is that when I look for replacement tubes, it is worthwhile to seriously consider NOS tubes rather than current production ones. I have not listened to re-issues, that is why I say, "consider."
I am really interested to hear from anyone who has experience with re-issues compared to NOS tubes. That might be an interesting tube-roll. Certainly my conclusion so far is that NOS 12ax7's are much, much better than current production JJ 12ax7's. It's a pity to think that good current production 12ax7's are so lame -- what to do when it is time to buy new tubes? Another question I have is, is there such a dramatic difference between current El34's, or other power output tubes, and NOS El34's?