[Spareribs]

I just won an auction for 5 Philco 12ax7 tubes on ebay.

Anyone know which company made these tubes and approximately when?

Five Vintage Used Philco 12AX7 Tubes - Tested Excellent - eBay (item 300324559936 end time Jun-28-09 18:11:29 PDT)

 

[derekbmn]

Sylvania.

 

[Oskari]

312 = Sylvania
6047 = YYWW date

 

[Spareribs]

thanks brotha!