Does anyone happen to know what the factory bias recommendations are for a 101B XTC? I know you can measure plate voltage and calculate it, but having owned a Shiva previously and biasing it, I know that there is usually some drift and that having been said Bogner usually has the factory bias nailed down to a particular value. For a Shiva, it was a bit lower than I would set up a Marshall for any given tube type. Wanted to see if that might be the same for an XTC.
The reason I am asking is I've noticed when pushed, my XTC gets a slight chorusing effect on it at higher volumes. Having worked on amps, built amps that's usually the sound you get when the tubes are biased hot and start to red plate.
I had the same chorusing effect on my Shiva when I had it and was able to get rid of it by adjusting the bias down. Interestingly enough with Bogners, while I've seen them sound like they might redplate, neither actually does. Which is good. Most Marshall's aren't that forgiving.
The reason I am asking is I've noticed when pushed, my XTC gets a slight chorusing effect on it at higher volumes. Having worked on amps, built amps that's usually the sound you get when the tubes are biased hot and start to red plate.
I had the same chorusing effect on my Shiva when I had it and was able to get rid of it by adjusting the bias down. Interestingly enough with Bogners, while I've seen them sound like they might redplate, neither actually does. Which is good. Most Marshall's aren't that forgiving.