Possible for mix IRF + FQA as complementary mosfet?

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Sorry if this sounds a silly question, but I don't think I've seen one done it yet.

Is it possibility to mix IRF and FQA as complementary mosfet ( e.g. IRF for P channel and FQA for N channel, or vice versa) provided similar transconductance? If not, why.

Thanks in advance.
 
I'm interested in the same issue.

Attached is a quick comparison of the available (except SFP9610) types that could be used as small signal mosfets.

Do I see it the right way when I say FQP3P20 + FQP3N30 are the best (available) complementary pair?
 

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  • IRF_FQP_comparison.jpg
    IRF_FQP_comparison.jpg
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This is a good and interesting thread but also very loaded.
As far as I know, there are no more complementary low power mosfets suitable for audio. Toshiba had the last ones and those are only available as NOS. Prakit on the forums has some available last i checked. So this mix n match approach may be the the only potential solution for production parts But to decide the most important parameters to match ain't always obvious.
I'd go for transconductance as THE most important parameter for a push pull stage.
 
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well - you didn't said in which apparatus you are planning to use them

F5.

(also, may be other Class AB Hexfet push pull amp.)

In addition what I try to understand is whether or not verticle mosfet P and N channel ( regardless of brands) can be mixed and matched .. based on the gain and Ciss at a particular fixed voltage
 
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yes , they can be mixed

additionally - P3 in F5 is your best friend , if you arm your self with THD analyzer , be it real one , or sound card based + adequate software

Thanks , Zen Mod.

I am now looking on the IRFP240 - P9240 datasheet. Say, at 30V Vgs 4.5V the Id of P240 is ~0.6A while P9240's one is 2A. Very different. I wonder how it actually happening when the working amp..... Solely let the NFB to solve the un-equal gain of both halves?
 
as said numerous time before (search for ilimzn's posts ) , if you are so concerned regarding complementarity of IRFP parts , use 240 and 9140 (if memory serves me well)

owever , I wouldn;t loose my sleep over that issue too much - Papa took all necessary care , prior to publishing that jewel project

use 2SJ/2SK parts (1058 and cousin ) there are plenty still around

as always , (pre)amp is greater than just sum of parts ; A class is pretty forgivable , and many times concept is much more important than slight nuances in parts selection

as I said - P3
 
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