query on the PSU of a preamp

ray_ben · 25th December 2005, 04:14 AM

Hello all,

I DIY a tube preamp based on a circuit from a old magazine.
It based on a 6DJ8 and 12AU7. I have some query on the power supply circuit. The circuit is attached.

Are the 2 Zener diodes (27V and 12V) in the right positions or they should be swapped?

Do you know the purpose of these 2 diodes?

regards, Ray

hacknet · 25th December 2005, 06:20 AM

i think its alright..

the 12v zener is to prevent the mosfet from destruction when the Voltage across the gate and drain exceeds the maxium allowable.

the 27v zener is supposed to do the same for the regulator.

marconi · 1st January 2006, 11:40 PM

between gate and source you mean...
But you are correct for the rest.

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25th December 2005, 06:20 AM	#2
hacknet diyAudio Member Join Date: Nov 2002 Location: sg	i think its alright.. the 12v zener is to prevent the mosfet from destruction when the Voltage across the gate and drain exceeds the maxium allowable. the 27v zener is supposed to do the same for the regulator.

1st January 2006, 11:40 PM	#3
marconi diyAudio Member Join Date: Apr 2004 Location: at home	between gate and source you mean... But you are correct for the rest.

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