Its too bad that this had to happen, since it gives the technologically squeamish something to hand wring about.
The technology isn't really anything ground breaking when you get right down to it. Basically an IC controlled bias monitoring/adjusting circuit no more complicated than a scientific calculator chip.
Even though the technology is old school, the idea is brilliant in that it makes running a four power tube amp like this much easier and less high maintenance, especially if you loose a 6L6 during a show! You also are freed to use less matched tubes and let the circuit tweak them into shape. You could never get away with that with any other tube power amp like this!
Mine has worked perfectly since I got my 100t many months back, and have rolled over a half dozen power tube sets through mine to see how well this little bias circuit could handle it. I even deliberately put widely unmatched 6L6s in mine to see what the amp would do, and damn if it didn't match them up and make them sound great together! Took it about four times longer than normal to stop blinking, but it did manage to bias them.
I even put a known shorted tube in mine. Not a bad short, but definitely a borderline 6L6, and my amp refused to use it!

It turned that tube socket and the other tube in that pair RED which kept the funky tube from possibly damaging the amp!
So, to all the hand wringers... GET A CLUE! The auto bias system is a fantastic feature and there is no need to fear it! Just educate yourselves as to what it is and what it does, and you will see why it is better to have it in there than not!
