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

You plug your original valves in and everything works.

You plug in a NOS valve and it quits working.

You have a bad connection (I'd doubt) or a bad NOS valve (I suspect)

Nothing needs to be soldered. Nothing is broke.

It never hurts to clean the pins, socket pins and or tighten them if needed. That's not the problem.

Think about what you said.. One valve works one doesn't.

Regards

Quick Update @oldhvymec @tvad 

 I’ve cleaned everything and all tubes below work in a separate LS1 preamp as the sole tube. 

Here’s a summary-

SP9 preamp scenario 1- current state-  both sovteks work but I want an amperex in V2 location

SP9 scenario 2 - desired state-  V2 with amperex works, but sovtek in V1 goes dark, no phono

SP9 scenario 3- V1 w Amperex works and phono works, but Sovtek in V2 goes dark and line stages don’t work

SP9 scenario 4- Gold Lion 6922 in V2 works, and Sovtek in V1 works, all sound good from all outputs 

SP9 scenario 5- swapping the Gold Lion locations from scenario 4 and all works and sounds good

Scenario 6 - all individual tubes work fine during extended listening when used in a separate LS1 that has a single tube in the gain stage. As hoped the Amperex sounds best if only I could get it working in a pair in the SP9 :(

Hi TVad. Thank you. 
The Amperex always works. It’s the others that stop working when the Amperex is put into the mix. 
Then they all work fine under extended use in a separate tube preamp. Hence my bafflement.