Hi, everyone,
I own the Meixing Mingda MC300-PRE vacuum valve 300B preamplifier.
On top of the preamp and adjacent to the 300 tubes, are bias adjusting potentiometers.
I recently purchased 2 PS Vane WE 300 replica tubes, which are on their way.
I wrote to Mingda and asked them how to bias adjust the new tubes.
The rep said after installing the tubes, if there is a hum that can be heard from 2 meters away, adjust the potentomer(s) until the hum is minimal.
My question to you folks is, how can I adjust the bias and maximize tube performance without setting the bias too high and sacrificing tube life (without going inside the preamp)?
I've never done this before!
Thanks for the help!
