VTA M-125 on 2 tubes

Hello
I just wanted to ask what the bias should be set at for 2 KT-88s. Also what tube position is recommended for the tubes. I switched over from electro harmonix 12BH7 to Gold Lion, Kevin's Stash 12AU7s. Switched the unit on and lost a Webber and a KT88. Going to run two tubes per mono until 8 new KT88s make it in.
Thanks in advance.

It should be .500 V. Half of what you normally bias.

Run in front position where it is cooler.

I think I also read on here that Bob says you can cut them back from 0.5 to 0.45 with no sound quality loss, cooler and improves tube life. I run my M125s with just a pair of KT120 each. Going to try 0.45 next time I check bias.

Here it is, a few replies down: https://dynacotubeaudio.forumotion.com/t4838-wz68-is-not-designed-for-use-in-hifi-amps

I would not bias a KT120 that low, 6550 maybe. Seems to be a fad these days, how low can you go.

There is nothing wrong with going lower. I run my KT120s at 0.40vdc each with no loss of performance. I recall an anecdote I read from a tube seller who spoke with an engineer from Sylvania back in the 80’s. The engineer recommended running power tubes at half their max dissipation and they’ll last longer.

I know many people run them higher but I could never find a good reason to do so other than someone’s opinion that they may sound better. One thing that we do know is the higher the bias the shorter the life span.