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Anyone else need more matched IRFP240/9610's

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I ran out and have one unfilled request. Does anyone else still need some? I was charging $100 plus shipping. for 4 matched sets of 6 and two matched pairs of 9610's (plus two for CS). If I get a couple of requests, I'll buy some more.

Best Regards,


P.S. How many people have completed projects with the fets recieved from me? Were there any issues? How does the amp sound. I have all parts, but have had no time to assemble the chassis...

Please email me at



That is the datasheet,

The package is a TO-247. It should be the same as the IRF240.

These are definately bigger than TO-220, but they should be the parts that the board is made with. The IRF9610's are TO-220.

Please send me direct mail at dherman@ksaria.com, so that I can add you to the list and give you payment options...

Best Regards,


P.S. The previous batch matched great. I only sold those groupings that had a max deviation of 20mV on VGS.
The IRF9610's had a max of 4mV.

For those who care, I ordered 250 IRFP240 and 150 IRF9610. With a bit of my time, this should yield some very good matched sets. I just wanted to make sure that people realize that I take this seriously, and do not skimp on getting good results. I match my resistors to .1% also (NOT selling these)...

So far, I have around six new clients. I think this type of collaboration (including the fine efforts of many many others) helps us all out who couldn't afford to get boards made or buy enough fets on our own. Can't wait to hear the details on the new projects. If my aleph takes much longer to assemble, perhaps it will become an Aleph-X or X100RE.

Thanks to all who have answered my never ending questions!

Joined 2002
Hi Dale, Guys,

I went ahead and ordered some extra 9610's (from Dale)
1.)The hope is to build a second Aleph at a later date.
2.)It sticks in the back of my head that in an old thread (un-findable with "Search") Mr. Pass said (not a quote, just from memory) that it does little good to match the differiential FETs. That the Pass method is to substitute 9610's until the DC offset disapears.

Does any one have experience with matched 9610's providing good results with a low DC offset voltage, or will it still be necessary to try several devices?:confused:

Slowly, but surely, I'm getting there.
Rodd Yamas***a
IRFP240's matched

As promised, here are the results of the output fet matching.

Special thanks to my wife, Rosie, for labeling all of the fets and to Peter Daniel for suggesting some test sockets which made testing easier.

I will sort out and send all packages on Saturday.

Best Regards,



  • irfp240.zip
    4.1 KB · Views: 98
Info on prices:

4 Sets of # IRFP240, 2 pairs IRF9610 Plus 2, Total #, Price
A5: 3 1 18 60
A4: 6 1 30 100
A3: 2 1 14 50
A2: 6 1 30 100
A1.2 12 1 54 250

Input Fets Only: Matched pairs plus spares:

2 6 25
4 12 50
6 18 75

Plus shipping: (US = $3.00), $5.00 WW

Paypal adds 3%

Best Regards,


Hi Guys,

The following shipments went out this morning via USPS:

Rodd Yamashita - IRF9610's
Harry Campbell III - Aleph 3 FETS
Robert Cowan - Aleph 2 FETS
Walter Chick - Aleph 5 FETS

All of the matched sets/pairs are marked on the outside of the static bags. If you want to know the values, check the posted results. All of the values are 4.XXX Volts Vgs.

Good luck on all of your projects.

P.S. Several people have expressed interest. I need to get form commitments (payment), so that you don't miss out. I may not do this again. It takes too much work...
Thanks much Dale. It is greatly appreciated.

The reason for two sets is:

One set is for me.

The other set is for when I blow up the first set.

If I bought only one set then I would violate the Murphy's Law corallary about parts conservation.

Actually, the second set is going to be the "raison d'etre" to learn CAD for my Fall semester students.

I haven't selected heatsinks yet. I've made heat dissipation and heatsinks research into an exercise for my summer intern.

I am leaning toward PCB's rather than PTP.

Thanks again,

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