Just picked up 10 nos mesa 12ax7's from the 80's

[shane]

labled either 7025 str 12ax7-a or spax7a

Are these run of the mill or the sought after chinese?
Thanks,
Shane

[sws1]

The SP tubes are very low noise. Mesa typically used those in the first input tube socket. They generally cost twice as much as the non-SP tubes.

I bet they are all chinese.

[shane]

I have had some really crappy chinese tubes over the years but now I hear about nos chinese from the 80's that sound excellent. Is this for real and how can I tell if I have the good chinese tubes?

[trisonic]

I think THD use those '80's tubes ( not labelled Mesa obviously) in their new shipments.

Pete.

[mtndog]

"...how can I tell if I have the good chinese tubes?"

Plug 'em in and play 'em.

[shane]

Thanks for everyone's help. I intend to put these on ebay and if they are sought after I would like to mention it in the ad. They sound good in my carr slant 6 but I don't want to misrepresent them. Any info on markings to look for etc would be appreciated. Thanks

[Slick51]

From Lord Valve's (Willy at NBS Electronics in Denver)... preamp tube catalog...

"NOS CHINESE 12AX7 GREY-PLATES

Along with my lucky score of "Silver Special" NOS Chinese
12AX7s, I also got ~500 pieces of the original "Beijing
production" Chinese 12AX7s. These are the same tubes that
all Mesa amps shipped with in the late 80s and all through
the 90s, and they were used in many Fenders, Marshalls,
Bogners, etc. Excellent for use in all guitar amps.

UPDATE 09/28/03 - I am finding a small but steady trickle
of these, at progressively higher prices. Still worth
the money.
EACH.......................................$15.00"

HTH
Slick51

[Wakarusa]

Originally posted by shane
I have had some really crappy chinese tubes over the years but now I hear about nos chinese from the 80's that sound excellent. Is this for real and how can I tell if I have the good chinese tubes?

There are "NOS" Chinese production that sound great. The grey plates are nice, the "silver specials" are simply fabulous. Particularly in old Fenders (to my ears anyhow...)

Here's what they look like:

http://www.wakarusaamp.com/misc_junk/technical/reference/tube_pix/index.html