BOSOZ MOSFET Bias

DavidMM · 12th November 2002, 04:07 PM

I am building the BOSOZ, unbalanced in, unbalanced out. For the BOZ, I have read on AA that the MOSFET bias should be about 28mA instead of 40mA. Should this also be done for the BOSOZ? And why?
Thanks.

Dave

halojoy · 12th November 2002, 05:16 PM

If you change the current,
(which I do not think will effect the performance
in any mentionable way,)
you get another voltage at the output. 20 volts it was.
Then you might need to change the value of R104
to get 20 volts again.

(Pass have chosen 20 volts.
And certainly he has a reason for that. Transistor operates good at 20 volts/40mA.)

Change of R104 will change the gain. R104/R108= 10

Gain is R104 and 5kpot+load, in paralellell.
Original this is about 800 ohms giving a gain of 8.

And if you want to keep gain at 8, and change R104
you will have to change R108 accordingly.

12th November 2002, 04:07 PM	#1
DavidMM diyAudio Member Join Date: May 2002 Location: Boston, MA	BOSOZ MOSFET Bias I am building the BOSOZ, unbalanced in, unbalanced out. For the BOZ, I have read on AA that the MOSFET bias should be about 28mA instead of 40mA. Should this also be done for the BOSOZ? And why? Thanks. Dave

12th November 2002, 05:16 PM	#2
halojoy On Hiatus Join Date: Nov 2002	R104 If you change the current, (which I do not think will effect the performance in any mentionable way,) you get another voltage at the output. 20 volts it was. Then you might need to change the value of R104 to get 20 volts again. (Pass have chosen 20 volts. And certainly he has a reason for that. Transistor operates good at 20 volts/40mA.) Change of R104 will change the gain. R104/R108= 10 Gain is R104 and 5kpot+load, in paralellell. Original this is about 800 ohms giving a gain of 8. And if you want to keep gain at 8, and change R104 you will have to change R108 accordingly.

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