I really enjoy my I/50, but I just replaced the left channel 6922EH driver tube. It was probably original, and I bought the amp used (it was used as a demo unit by a reviewer who must have played it). No biasing needed, only the power (6550) tubes need biasing. It is a shame the amp has to be sent somewhere and can’t be modded for user servicability or auto-biasing. I have also a Willsenton R8, KT-88 push-pull integrated, with similar specs, and that unit is set up for user biasing which is not difficult. I have to wonder whether they will continue the I/50 with a similar integrated offering what are considered improvements to the I/50.
