BeatleFred
Super Member
Its for that very reason you mentioned (the pot being so sensitive) that it should be adjusted very carefully. Unless the adjuster has very steady fingers, all it can take is the slightest turn and the bias value can soar to some high value.
And its likely, as you observed, that the value can drift from what it was set to. 3 minutes, as shown in the manual seems way too short of a time period to me. I'd atleast let it warm up to operating temperature before making the measurement and adjusting anything. Someone Online who runs a hi fi business, in an email to me, he strongly recommended leaving an amp On for 72 hours before performing any checks. He also recommends leaving amps On all the time, but that can go into a discussion unto itself.
In my case, the BA-5K's I have seem to run a bit warmer than I think they should. Not right away, but after about an hour when I place my hand on the cover, behind the transformers, its hot, not super-burning hot, and the fan isnt on, but very warm. I think the bias needs to be lowered closer to the 180mA range. I was going to try it last night, but I couldnt find the right size socket amongst those I had, thus why I asked if you knew offhand what the size was.
B/F
And its likely, as you observed, that the value can drift from what it was set to. 3 minutes, as shown in the manual seems way too short of a time period to me. I'd atleast let it warm up to operating temperature before making the measurement and adjusting anything. Someone Online who runs a hi fi business, in an email to me, he strongly recommended leaving an amp On for 72 hours before performing any checks. He also recommends leaving amps On all the time, but that can go into a discussion unto itself.
In my case, the BA-5K's I have seem to run a bit warmer than I think they should. Not right away, but after about an hour when I place my hand on the cover, behind the transformers, its hot, not super-burning hot, and the fan isnt on, but very warm. I think the bias needs to be lowered closer to the 180mA range. I was going to try it last night, but I couldnt find the right size socket amongst those I had, thus why I asked if you knew offhand what the size was.
B/F
