Why aren't new vacuum tubes as good as old ones?

This thread is astonishing. Many new tubes are fabulous (KT120s have been nearly unanimously accepted as great), guitar amps use FAR more of the available tubes than home audio geeks ever will, and new "boutique" tube amps and reissued amps sound mostly better than ever (and 99% of 'em are sold with new tubes). Tubes like the high end Psvanes are beautiful, very well made, and sound amazing. I've only had a few tubes not do the job or fail in my many years of using 'em, and among those were NOS tubes. So, basically, you're all insane.

I hope Atmasphere is right. The man over a Vintage Tube Services in Mich. told me it is an human craft. Like Ebm says. You da man Ebm. Anyway he told me the extent they went to to produce good ones. And that to bring new tubes to the level of the good old tubes just a computerized regimented process can't really match. It hasn't yet. It sounds like it is still is a human endeavor to make the best tubes. I have had several tubes and can hear a big improvement with my NOS over new stock. Anyway it would be nice if it does.

Whew! That's a relief. Thanks Wolf. Can you recommend a really good 7189?

My experience indicates that new tubes are as good or better than old tubes in most cases, and since there are new designs that hadn't existed before now it renders that argument moot for those examples. I use Psvane 12AX7T-IIs in my hifi and guitar amps that I believe are better than any old stock 12AX7 I've used, and KT120s are amazing, didn't exist until recently, and have been adopted as a standard tube by some heavy hitter amp companies. The myth of old tubes being better is simply silly...they may sound different, people might prefer them, but design, construction quality, and consistency is fine for new tubes from many manufacturers.