RCA Clear Top Red Tip Low Noise 6CG7 6FQ7 Vacuum Tube With Shields Number It is dead quiet when

It is dead quiet when the preamp is muted and has excellent frequency response and sound-staging

They are dead quiet when the CD player is paused and have excellent frequency response

Two end links are available

I wish I could tell you how they sound and from what I can suss out

perfectly-matched pair of RCA black plate

RCA Clear Top Red Tip Low Noise 6CG7 6FQ7 Vacuum Tube With Shields Number It is dead quiet whenThis new old stock testing RCA clear top, red tip (low noise) 6CG7 6FQ7 dual triode was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. It measured 82 91 where minimum (65%) is 50 50 and 100% is 77 77. This tube has steel support rods; a side D; a clear top with red paint (indicating it is a selected, low noise tube; gray plates and excellent flashing. There is a shield between the triodes