Just installed tung-sol tubes in the V1 and V2 slot of my 6505+ what a diffence that harshness in the highs at low volumes went away. Heres some pics and a shitty video i did real quick after a few rum and cokes and a 5 min tube change (hey at least its a real video without a Djent backing track with full instruments to thicken it up) .
Nice. I put a Tung-Sol in V1 of my RD45, and it made a night and day difference from the stock Ruby. Really opened up an otherwise dark amp. Much more articulate, and cut down on a lot of noise too. Tung-Sol rules!