BOZ..how to set bias? need help

tone · 3rd December 2002, 05:21 PM

Boz running at 50volts..the preamp is working but clipping..can someone guide me to how to set the bias? im getting only 4volts after resistor R103.. and 1.2volts at IRF150 Source pin before 100ohm (R108)..pls help..thanks in advance..

rgds
tone

Henrik · 3rd December 2002, 07:04 PM

The powermosfet IRF150 is not suitable for BOZ. You should use some TO220 fets like IRF610 or IRF510, then every thing will work.

eLarson · 4th December 2002, 03:07 PM

I concur with the IRF510 suggestion. I've been using that config
for the last few years and its working very well.

Erik

Taco · 4th December 2002, 03:14 PM

I have used the IRF610 but the amp also clips with very high inputs. (>1,5 volt). I put on the input a 100k POT in series. And adjusted until it was gone.

See also:
ESP Death of Zen preamp vs BOZ

3rd December 2002, 05:21 PM	#1
tone diyAudio Member Join Date: Aug 2002 Location: Malaysia	BOZ..how to set bias? need help Boz running at 50volts..the preamp is working but clipping..can someone guide me to how to set the bias? im getting only 4volts after resistor R103.. and 1.2volts at IRF150 Source pin before 100ohm (R108)..pls help..thanks in advance.. rgds tone

3rd December 2002, 07:04 PM	#2
Henrik diyAudio Member Join Date: Feb 2002 Location: Copenhagen Denmark	The powermosfet IRF150 is not suitable for BOZ. You should use some TO220 fets like IRF610 or IRF510, then every thing will work. __________________ Henrik

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4th December 2002, 03:07 PM	#3
eLarson diyAudio Member Join Date: Aug 2002 Location: Gaithersburg, MD	I concur with the IRF510 suggestion. I've been using that config for the last few years and its working very well. Erik

4th December 2002, 03:14 PM	#4
Taco diyAudio Member Join Date: Nov 2002 Location: Place in the Netherlands	I have used the IRF610 but the amp also clips with very high inputs. (>1,5 volt). I put on the input a 100k POT in series. And adjusted until it was gone. See also: ESP Death of Zen preamp vs BOZ

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