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

I feel better already.

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.

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.

I use new JJ EL84s (7189s) in my Burriss Royal Bluesman amp, and they sound great.

Here's an interesting tidbit from the Atma-Sphere FAQ page:

"Atma-Sphere equipment is designed to work with commonly available tubes, making our products easy to live with. The 6SN7 tubes we use are produced in China but there are many aftermarket versions available. The output tubes are Sovtek, Svetlana or Chinese. The miniature triodes used in the preamps such as the 12AT7 and the 12AU7 are usually Chinese. Other types of tubes may be available on request."

I think you should avoid the 6SN7s from that manufacturer as clearly something's wrong...but preamp tubes or driver tubes generally should last a very long time. Also, 250 bucks is some large cash for 4 driver or preamp tubes...sort of my lifetime preamp tube cost, although I can see (at thetubestore anyway) 6SN7s seem pricier than some other preamp types.

I confess I use Mullard CV4024s, but mostly because the JAN Phillips 12AT7s they replaced self destructed after about a month, and I like the "start-up flash" the Mullards display...we need more tubes with that start-up flashing...it's exciting. Note that the EH 12AT7s were fine, I was simply overcome with curiosity. I do like the new Mullard 12AX7s in my Burriss guitar amp, but they, sadly, don't flash on start-up.

There is some subject dodging going on here...like regarding KT120 tubes. Do they have badly fired getters? Why do many feel they are great sounding, even compared to NOS whatever? Why have my 120s lasted 2 years of daily abuse and still show no signs of age? Do Psvane Treasures have badly fired getters? Why do the ones I use sound fabulous? Is New Sensor a factory full of worthless slackers pounding out junk? My re-issued New Sensor Mullards in my Class A guitar amp are perfect...why? Am I insane? I am? Oh...well...nevermind.

I had a sloppily made Psvane pair that I sent back, but that was cosmetic really (on one tube) and it was a matched pair...they did seem to sound OK. The next pair was better, and have remained in their sockets. I wonder what the number of bad 120s is relative to others at ARC, as there hasn't been much reporting of 120 failures otherwise, or at least from what I found in my research (research...ha...more like "lazily poking around").

It's fype.

I use some "vintage" tubes...I like chrome dome Sylvanias and Mullards that "flash." I don't know why manufacturers keep putting KT150s, KT120s, and Gold Lion KT88s in the amps they build...don't they know new tubes suck? They even fooled me into enjoying all of those and thinking they sounded great...some for years...

How many tube guitar amps are out there? Small niche? I'd bet they're 90% of the tube market...gotta scratch that niche.

I suggest you try what Billy Gibbons allegedly did with a bunch of amps...his crew piled them up in a sort of large box configuration and stuck a mic in the middle of the heap...not sure how it sounded but hey, why not?