zen and irfp240

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nightdrg

nightdrg

Member
Joined 2003
dev.segv.cc/
Hi,
I'm newbie in audio and i'm working with Zen first variation. I use IRFP240 instead of IRFP140 (i can't find IRFP140 in my country). After a few seconds R1 (0R33/2W) is really hot and it smokes. I take 2R0/5W inestead of it. Now i have about 1.1V on R1. Is it OK? Or should i change R6/R7?

regards,
pawel.
 
moe29

moe29

Member
Joined 2002
A value of 0.33 ohm, 2 watts for R1 works - if the circuit has been
correctly assembled. Other parts will work, as Mr. Pass mentions
in the article, but i would say it's probably best to stick as close as
you can to the parts list for your first build. After you have a
working amp, feel free to experiment from that point ;) - A good
place to start would be the upgrades reccomended in the
Zen Revisited article that can be found on the PassDiy web site.
 
MikeW

MikeW

Member
Joined 2002
Bias

The voltage drop should be .66 volts. It is set by the base to emitter drop of Q3. The value of R0 (.47 ohm) and R1(1 ohm) set the bias. They are .33 ohms together it is .66/.33 or 2 amp bias. If R0 (2 ohm) and R1(1 ohm) that would be .66 volts/.66 ohms or 1 amp bias.
IRFP 240 should work fine. Good luck.:D
 
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