Why do old tubes sound better than current tubes?

Doug brings up a great point and I defer to his broader experience. I use mostly vintage gear and have not tried every new small signal tube out there. So, as he so correctly points out, my experience is limited.

We use tube curves based on the old tubes to design gear. Modern tubes behave slightly differently and most certainly the Russian tubes are NOT direct drop-in replacements for old Mullard designs. Russian Tubes today can handle more current in many designs and require it to sound good.
Much of the NOS stuff is fraud and nonsense IMO, as many of the "better" sounding tubes have no bass or treble thus softening a truly nasty speaker,cartridge or CD player and making an awful system palatable. That is, when the NOS tube is what it has been labeled or is not a completely worn out "pull".

Richard

I picked up a few of the new Genalex 12AX7GENGP tubes from NS and did an audition between them and the 04/60's Telefunken I was using in my C500T.

Guess what -- even though still early, and the Genalex have only 5 hours on them or so since the swap out -- I like what I'm hearing & so, they remain in the MC slots.

Impressive so far folks.

Bob

I picked up a few of the new Genalex 12AX7GENGP tubes from NS and did an audition over a weekend between them and the 04/60's Telefunken I was using in my C500T.

Guess what -- even though still early, and the Genalex have only 5 hours on them or so since the swap out -- I like what I'm hearing & so, they remain in the MC slots.

Impressive so far folks.

Bob

Search the archives, this question seems to come up once a month or so.