I use to constantly check my bias when I first entered into the amber light.
So concerned was I.
As time went on I only checked my bias after 20minutes of warm up time and then once again in another hour...
I was listening to my music after 5minutes of turning on the m125's.
What I have discovered is that if I do not check my bias until 30-40 minutes into play it is just as I left it the day before. This new discovery had me scratching my head.
Why is it that way?
I do have a Variac and and a kil-O -watt making sure before I turn on the m125's the voltage reading in my house/system is no more than 119.6. This discovery is new to me and I was wondering why I never read about this conduldrum.
So the longer I have my tubes warm up from first turning on my m125's the more they are in tune (so to speak)
Happy to discover this working fact.