IR vs Fairchild?

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Apogee

Apogee

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Joined 2002
#1
I am about to lay in some stock of IRFP parts for various projects.

Regarding IRFP 240/244's is it worth paying roughly double for the Fairchild parts? I remember there being conversation about a bump in the transfer function of the IR parts, but I also remember Nelson and others stating it wasn't necessarily a bad thing.

With regard to the 9240's is the answer the same?

If the money was secondary, which parts are better to buy for hifi use?

Any input would be appreciated!

Thanks,

Steve
 
#3
Typically, so am I. However, I'm afraid before long (a few years) these through-hole parts will become more and more difficult to get. Hence, in the long run, on a quantity of 100 devices $100-$150 in the grand scheme of things isn't going to make any difference. I'd much rather grab the best parts for my stash while I can.

Also, I don't have any way to test individual parts for distortion, transfer function, etc. so I figured best to ask.

Thanks for your help!

Steve
 
#4
I've had both in an F5. I went from Fairchilds to IRF's because I blew up the Fairchilds in an "accident". There was about a two week period between listening to the F5 w/Fairchilds and listening to the F5 w/IRF's. I don't know that I noticed any difference. If anything, I prefer the F5 now w/IRF's.
 
#9
Bigun said:
IRFP 240/244's -- in some ways these are the 2N3055's of the FET world, they are are ubiquitous and outclassed by many more modern devices yet still very much used. OK perhaps not as bad as the 2n3055 😀
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If that is the case, what would you recommend instead?

I was looking at the Toshiba devices mentioned above but they are getting difficult to find because they're no longer made. They're also darn expensive....

Suggestions for better devices if I'm building Pass stuff?

Thanks,

Steve
 
#10
Apogee said:
If that is the case, what would you recommend instead?

I was looking at the Toshiba devices mentioned above but they are getting difficult to find because they're no longer made. They're also darn expensive....

Suggestions for better devices if I'm building Pass stuff?

Thanks,

Steve
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Both the aforementioned fairchild and toshiba mosfets are discontinued. If you wsnt to buy hundreds of something to stockpile its going to have to be the irf parts. Ive seen people playing with other mosfets and laterals with pass designs but they are usually also discontinued parts which are expensive or hard to get.

If you are interested in buying a few hundred mosfets to insure you can build amps in the future its going to have to be the irf parts unless you have money to burn. If you are interested in knowing what is the best sounding mosfet in pass designs...well thats open for debate.
 
#11
Apogee said:
If that is the case, what would you recommend instead?
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Hi Steve,

Actually, I think your plan to buy a qty of IRFs for the price break makes good sense if you expect to use them. It means you will likely get a batch of parts that are fairly close in their parameters and that they are not fake etc. I think it will be a long time before it gets hard to obtain these parts but it's nice to know you have them in stock. And they are so popular with PASS amps and other amps that there will always be plenty of projects you can use them for (and likely that you can find somebody who will take them off your hands if you don't need them).

As others have said, parts with better on-paper performance will cost more money but no guarantee that you will find them to sound better than the IRFs as it becomes a subjective judgment. There are amplifiers where upgrading from 2N3055 to modern parts makes the amplifier unstable due to the 'better specifications' of the modern parts.
 
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