So, I can't get the thing to bias. I'm trying to avoid cranking the screw left and right hard. Just minor tweeks and play for a while. But it just won't settle in properly biased. It's a late SLM era. I recently bought it used so I don't know the age of the tubes. What should I look for? What should I try? I'v done a little searching and several threads point to the 12au7 tubes. There seems to be a debate over "gain matched" or not. But that's as far as I got before getting lost in a sea of information that didn't help.