RCA 6V6GT "Gray Glass"
These are the famous RCA 6V6GT "GRAY GLASS" Tubes from the 40's and 50's that are so highly prized and universally regarded as the best sounding 6V6GT tube ever. All tubes are NOS (New Old Stock) versions of this famous tube.
What about the GRAY GLASS?
The "gray glass" is reported to be an RF shielding material that is sprayed on inside the tube to absorb stray electrons. This gray coating often hides the plates from view, and is often streaked where the spacers were inserted during installation. The RCA gray glass 6V6GT is in such demand that worldwide stocks of this "out-of-production" tube are rapidly dwindling. We have great difficulty finding them in premium condition and reject more than we keep.
Why not just use the new current production versions?
Simple! It's the sound. The current production tubes just cannot compare to glorious, rich, smooth sound of these vintage tubes.
RCA private labeled this tube for many different companies throughout the years. The RCA manufactured, private branded versions are EXACTLY the same as the RCA branded versions!
The Firestone 6V6 Mono blocks are shipped with these NOS RCA 6V6GT's as standard equipment.