View Single Post
Old 3rd November 2021 | Show parent
Lives for gear
kludgeaudio's Avatar
Originally Posted by M50k ➡️
It's always puzzled me how M50/49s and U47s are kept alive when the tubes go - is there that much AC701 and VF14 NOS still out there?
The thing is, those microphones were designed for exceptionally long tube life. Part of what makes for the coloration of the U47 is how they run the tube with low filament voltage for low emission and long lifespan, so tubes really do last a lifetime. That's a requirement in the broadcast world.

The truth is there aren't very many VF14s out there anymore, even though they were picked originally because they were plentiful and cheap on the war surplus market. For a long time people would just swap the tubes in the mikes when they suspected anything, because the tubes were cheap and easy to replace. Now they aren't so plentiful and they sure aren't so cheap.

Worst case: when the VF14 fails you put the nuvistor kit in there and the mike sounds better with the nuvistor anyway...