Match the NNN and the PPP. Don't worry so much about the N and P having the same values.
Purchase a bunch and match your own. This gives you experience and spares.
Purchase a bunch and match your own. This gives you experience and spares.
carpenter said:
Ugly!
(Choky will wait until you post a pic of a finished amp and present it in its full ugliness 😀 )
p.s. In the dark,it doesn't matter if its ugly or not, as long as it sounds good!😉
Vix said:
So true; I've been told that the same can be said of the person in our bed, sleeping next to us...😀 😉
woodie
please use metal screws for output fets ; these plastic ones are just begging for bubble gum effect ....... then pufff!
please use metal screws for output fets ; these plastic ones are just begging for bubble gum effect ....... then pufff!
You guys are funny...😀
Metal screws carry the fet tab through the mica and into the heatsink, thereby causing a direct short!
Metal screws carry the fet tab through the mica and into the heatsink, thereby causing a direct short!
carpenter said:
Which is why you use an insulator for the bolt 😉
Really, the nylon bolts are going to give up the ghost sooner than you expect.
Magura 🙂
Magura said:
Well, now that you mention it, where do I get a screw kit that isolates that tab. I've been looking everywhere.
carpenter said:
No idea, I just machined some of a piece of FR4 board, last time I needed those.
Magura 🙂
Re: Re: N to P matching
Thanks for info. I got similar result.
I measured Vgs with 20pcs each of IRFP240 and IRFP9240.
Luckily, I found that deviation of Vgs among each pieces was
not bad at all. And, the average absolute Vgs of IRFP9240 group
was about 0.17V higher than the average Vs of IRFP240 group.
By the way, did you use the original R of 22.1K between
the reference and cathode of TL431?
What is the Vdc measured between the gate of N-Mosfet
and the gate of P-Mosfet on the bias condition?
carpenter said:
Thanks for info. I got similar result.
I measured Vgs with 20pcs each of IRFP240 and IRFP9240.
Luckily, I found that deviation of Vgs among each pieces was
not bad at all. And, the average absolute Vgs of IRFP9240 group
was about 0.17V higher than the average Vs of IRFP240 group.
By the way, did you use the original R of 22.1K between
the reference and cathode of TL431?
What is the Vdc measured between the gate of N-Mosfet
and the gate of P-Mosfet on the bias condition?
carpenter said:
how do I know that when I'm living in Serbia?
look at
CookBook - you'll see them on cover pics........that's dreky nipple, nothing else
Magura said:
why I'm not surprised ?
I'll go with the bar.
babowana: -4.26 volts on the P gate and 4.10 volts on the N gate.
Interesting that there's almost the same mismatch as the Vgs readings.
babowana: -4.26 volts on the P gate and 4.10 volts on the N gate.
Interesting that there's almost the same mismatch as the Vgs readings.