There is a physical defect in the valve. I wouldn't use it. I'll bet the wire is to thick. Simple explanation ay. The problem is the SQ of the valve will reflect that THICK (er) wire. The older it gets the better it will read, but it will NEVER be a great sounding valve. The last test of a valve is to listen to it, believe it or not.. How many do that?. Warm it up and listen.. LOL The only reason I couldn't make living at it.. TO DARN PICKY..
Regards
Regards