I just completed my VTA70 upgrade on my ST70 and it sounds great. As I am biasing my tubes, I noticed some unexpected behavior. Since there is a bias pot for each tube, I expect them to be adjusted independently but when I adjust either tube on the left, the bias for both tubes have the same value and go up and down in tandem as I adjust either of the bias pots. Is this expected behavior or did I forget to remove a jumper wire or something?
Note that left and right channels bias independently but the tubes in either right or left seem to bias together. I am checking bias through the front octal sockets.
What do you guys think?