i got a Audio Research D160 tube amplifier, but it's no tubes.No biasing is needed for the small signal tubes.
so i need to buy all the new tubes, but i don't know how to adjust the tubes bias,
the (12ax7 6922 12at7 12bh7 )tubes need to adjust the bias? or just the 6550 need to adjust the bias ？
For biasing the 6550 power tubes go #5 and start there.