I haven't had this problem when replacing the old texas instrument darlingtons for TIP's....or at least not that I have noticed. But I have read some comments by Dillen where he advocates the use of good old stock transistors if one can get them.....

Craig

Idle current set correctly?

Martin

Yupp  5,8 mV or there abouts across top of output resistor pairs, just like before, stable

Hmmm.....will need to check, but I think the setting should be 5,5mv from the top of one resistor to ground, 12-15mv across the top of both.....Martin?

Craig

Just checked back on my previous posts and 5.5mv across the topd of the emitter resistors is good (the 12-15 refers to the mA measurement)

Craig

After all of the BM4400 I have set up one would think I should know this by now! 10-15 mV across both resistors, 5.5mV across the tops of both (which is one resistor) 😐

Yepp on the tops, just like Beolover :=)

Forget about the burning in of semiconductors.
I still have to see any scientific proof of any difference, and I have never in my several decades with electronics in general and B&O audio in
particular experienced anything to that effect myself.

Are the new output stage darlingtons chinese counterfeits? Sorry for asking, but even "trusted suppliers" can't safely say, that they are sellling genuine parts. Hence the above reference to my saying that I would very often prefer to fit good used original output stage transistors rather than buy new of unknown origin.

Did you fit low-ESR capacitors in the output stage? If you did I suggest you replace them with standard types.

Martin

Dillen wrote:

Forget about the burning in of semiconductors.
I still have to see any scientific proof of any difference, and I have never in my several decades with electronics in general and B&O audio in
particular experienced anything to that effect myself.

Are the new output stage darlingtons chinese counterfeits? Sorry for asking, but even "trusted suppliers" can't safely say, that they are sellling genuine parts. Hence the above reference to my saying that I would very often prefer to fit good used original output stage transistors rather than buy new of unknown origin.

Did you fit low-ESR capacitors in the output stage? If you did I suggest you replace them with standard types.

Martin

I'm with Martin about this.  Is your BM4400 was recapped?... with what?