Rare White Tip NOS Pair of The Highest Medical Grade Telefunken 12ax7/ecc83 1952 made for Boonton

The finest Telefunken diamond mark, NOS, that have been further aftermarket screened for low noise, low microphonics, and balance, for critical use in medical equipment. These have the RARE WHITE painted tips, and were only available for the Leeds & Northrup, Boonton, Tektronix test equipment market, or Grass medical equipment. The white tip is the highest grade of these rare selected tubes. Critical use in hospital or aerospace test equipment demanded tubes with super low noise, and tightly controlled output, and these beauties deliver! Better and tighter selection than even the costly ECC803S tubes. The ultimate tube for tube mics and mic preamps! Very fine, very rare tubes, in great demand, especially this selected version. Excellent labels on these. These are all Tele labeled, and have the distinctive Grass Valley white painted tips. All are the real deal, with the diamond mark in the bottom glass. Incredibly accurate, the amazing sound image emerges out of a dead quiet background. The best of the best.