is there a way to tighten pins in tube sockets?

Get some socket savers. They come in 8 or 9 pin. Before you put them in just squeeze the female pins a tad and then stick the socket saver in so it fits tight. Now you will always replace your tubes in the socket saver not the sockets on your amp. I use them on my amps and they solve the problem.

I forgot to mention. They will raise your tubes about an inch taller so if you have a cover over tubes make sure they will clear if no cover no problem.

+1 for the socket savers ONCE the pins are tightened. I got the ones from the tubemonger and I will say the sockets on the saver are real tight. I had a loose socket where the bias would drift and lost some pretty expensive tubes as a result before figuring that out. For me I had the sockets replaced first.

I was thinking there might be a "special tool" for performing the tighten operation. Since I work on BMW's, they have a "special tool" for everything. I'll take a look at the amp this weekend and see what's possible.