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-   -   how many of IRFP240 will match in one batch of 100 units? (http://www.diyaudio.com/forums/pass-labs/230167-how-many-irfp240-will-match-one-batch-100-units.html)

rhythmsandy 16th February 2013 05:37 PM

how many of IRFP240 will match in one batch of 100 units?
 
I am about to order the IRFP240 and 9240 with 610 and 9610 I just wanted to know that in the reel of 100 how many of them are matching in how many sets? just to order the quantity.

Nisbeth 16th February 2013 08:51 PM

43 ;)

You don't really know that until you get them and start measuring, do you?

/U.

Nelson Pass 17th February 2013 02:57 PM

How tightly are you matching them, and what is the group size?

For .1v Vgs and pairs, it will be nearly all of them.

:cool:

KatieandDad 17th February 2013 03:58 PM

I bought 50 to get four groups of 6 for an Aleph 4 build.

rhythmsandy 17th February 2013 04:10 PM

it would be a set of 7 but tolerances... I believe Nelson sir you should tell us how good it has to be how many millivolts

rhythmsandy 17th February 2013 04:11 PM

original IRF and Vishay both are same or different?

KatieandDad 17th February 2013 04:30 PM

Are you after 7 matches ? Seems like an odd number.

In the Pass amps only the MOSFETs in one leg need to be matched, not one leg to another.

Unless you are building an Aleph X which is a different kettle of fish.

nigelwright7557 17th February 2013 04:56 PM

I have never found the need to match 240/9240's
The source resistor should help balance things.

Nelson Pass 17th February 2013 11:02 PM

It is rare that anyone bothers to try to match P to N's. In an output
stage the big thing is to get DC current sharing so that no one device
hogs the current.

:cool:

oneplustwo 17th February 2013 11:07 PM

I just went through this exercise with just the 240's for an Aleph X build. I was shooting for quads within 0.010V of each other or better and was able to get matches for about 80% of them. There were a few that were pretty far off for whatever reason (edge of the die?) and a few that were grouped tightly for 3 or a pair, but not four.


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