New vs. Old

[playonit]

So I guess.. I wonder ...... since I am not really well versed on actual tube knowledge.. with NOS and the older tubes becoming more and more expensive and harder to come by... what makes the nos/older tubes more desirable?? What makes newer tubes inferior? if that is actually the case?

[Cantplay]

Mostly, yes.

NOS tubes were made to very high standard. Alloys used make a big difference.

Some technologies like thoriated tungsten heaters are very dangerous or expensive to produce today, so lower cost options are used.

Every metal object I see from China has scrimped on metallurgy, Its no wonder their tubes don't exceed NOS.

There are some decent tubes from Russia recently, EF86, and some of the EL34's.

Has anyone yet made a 12ax7 better than the <>Telefunken, or triple mica 5 stars? NO.

John

[playonit]

Thanks for the info... I have all Nos Tubes in all my builds pre-amp sections and newer manufactured tubes in the power sections.. Like the Tung-Sol 5881 re-issues in my 5e7 build and the Mullard EL84's in my Dc30 circuit.. I still keep an open eye out for any NOS bargains that fit my bill...