Tube Replacement Problem - Audio Research SP9 MKiii- V1 Tube Goes Dark w/ new V2 installed


Hi, Does anyone have any suggestions??

I’ve tried replacing the original Sovtek 6922 V2 position tube with a vintage NOS 6DJ8/6922 Amperex SQ circa 1969, but the original V1 position phono tube goes dark and I get no sound from my turntable. The new tube in V2 position works fine and sounds terrific despite the no phono with the darkened Sovtek in V1.

However, when I go back to the original 6922s in V1 and V2 position everything works fine and tubes light as normal. Do the new tubes need to replaced as a matched pair or is there anything else that I should know about replacing a single tube?

The unit is a factory SP9 MKIII.
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Possibility 2 is that the old V1 has an internal bad connection to its heater. That is the simplest fix! Just install a new tube with a working heater! Try the wiggle test! A bad internal heater connection can be intermittent also!
Thank you RJ for the suggestions. I’ve tried all 3 and no luck. Back to the originals and all is working as normal. :( I’m gonna have to have it checked out Bc I’m not a great solder guy. 
Is it safe to touch and pull the tubes while on? I see a couple voltage warnings :O :)