Yes, which is my point, since you referred earlier to 110V. The DC output is not regulated and will vary by a similar % to the AC line voltage in the primary winding. That will differ from Bryston's nominal 120V, according to your local supply condition.
AndrewT makes an important point about the transformer's "regulation" which has a specific meaning here. In general terms, it is the % secondary voltage drop according to maximum rated load. However, I doubt there is any "leakage" that would cause around 10% voltage drop, since it implies significant power dissipation and possibly damage. Disconnect the power supply from the amplifiers, measure primary and secondary voltages as well as DC again and find out.
Andrew, Ian, thank you for your inputs I will do measurement and report. But looks like the DC offset leakage on terminals issue is somewhere else...
I think my new 10000uF 100v caps will arrive within 2 weeks, we will see if cans will change the DC offset.
I think my new 10000uF 100v caps will arrive within 2 weeks, we will see if cans will change the DC offset.
Andrwe, Ian, thank you for the feedback. My PSU caps arrived, replaced but still DC offset. I gather some feedback in other thread http://www.diyaudio.com/forums/parts/151392-best-electrolytic-capacitors-72.html#post4875700, but maybe the right thing to keep posting about Bryston 3B in here.
I measure the voltage on NFB at the point after the 470/16 cap, and got DC on both channels (about -8,14mV and -9.4mV), so maybe matching pairs 2N5087 and 2N5210 will be a good idea but both are EOL now.
I good advice was given by Anatech http://www.diyaudio.com/forums/parts/151392-best-electrolytic-capacitors-72.html#post4876947, looks like I need to try this way.
I measure the voltage on NFB at the point after the 470/16 cap, and got DC on both channels (about -8,14mV and -9.4mV), so maybe matching pairs 2N5087 and 2N5210 will be a good idea but both are EOL now.
I good advice was given by Anatech http://www.diyaudio.com/forums/parts/151392-best-electrolytic-capacitors-72.html#post4876947, looks like I need to try this way.
PSU caps should have very little influence on the offset, as long as +/- supply voltage is the same.
What offset are you getting at the output? Up to 25mV or even 50mV should be fine. Anatech's advice about matching the input transistors is a very good one, which you should undertake.
But I think you should try this trick first. Unsolder one end of one of the 15K resistors on the LTP and solder a 50K multiturn trimpot in its place, set close to 15K. Try to null the offset increasing or decreasing the trim.
You may try the same unsoldering one end on the 47K input resistor.
What offset are you getting at the output? Up to 25mV or even 50mV should be fine. Anatech's advice about matching the input transistors is a very good one, which you should undertake.
But I think you should try this trick first. Unsolder one end of one of the 15K resistors on the LTP and solder a 50K multiturn trimpot in its place, set close to 15K. Try to null the offset increasing or decreasing the trim.
You may try the same unsoldering one end on the 47K input resistor.
I thought I would share my adventure in Bryston biasing.
I decided to bias until all crossover distortion had gone.
Bryston 4B Refurbish - YouTube
I decided to bias until all crossover distortion had gone.
Bryston 4B Refurbish - YouTube