Fairchild interest alternatives

[buzzforb]

I am going to open this up to discuss alternatives to the N channel parts spec'd in the the F5T. The P cahnnel parts can still be had, but the 19n20C are pretty much a no go. There are plenty out there, but i have found a 100% fake rate. No one has original boxes, and without it, your chances are sketchy at best. There are over 50,000 of these things floatig around in Asia, some being made in 10' and later. That should tell you all you need to know. There are two other 19n20 parts, the standard version, and the "l" version, both with increasing Yfs and Ciss. Of these two, the standard part is a better match on paper, the 19n20"L" part has double the Yfs(transconductance) and double the Ciss. THis is still available. Another EOL part that i think matches better on paper is the 12n25C. It is EOL, but still available, the question being one of sufficient quantity. OTher than these parts, the only new parts i found that look close are the FQA32N20C and FQA28N15. Other than these, we have the option of the smaller die package FQP of the original parts. I am going to start a poll so that we can vote. I'll look at the results and we will go from there. Please let anyone on the orginal GB know.

 

[fdlsys]

Paapaaaa!!! Help!!

 

[Gyuri]

Sometimes I have that feeling of mine, Papa makes his amplifiers from unattainable components, because it is not possible to make a copy from these so.
This was a malicious comment now.

Let somebody correct me if this is not so.

 

[fdlsys]

Sometimes I have that feeling of mine, Papa makes his amplifiers from unattainable components, because it is not possible to make a copy from these so.
This was a malicious comment now.

Let somebody correct me if this is not so.

Would it make any difference even if a 100 of us corrects you?

 

[buzzforb]

Sometimes I have that feeling of mine, Papa makes his amplifiers from unattainable components, because it is not possible to make a copy from these so.
This was a malicious comment now.

Let somebody correct me if this is not so.

I think that may be a stretch. You could have gotten these components easily when the F4 was released. One ofthe early builders, Cviller, made it well known these were the components used by Nelson.

 

[Gyuri]

As mentioned above, this was just a malicious comment.
You know, I am like that than Gargamel.
Ugly old small bald evil.


I was thinking about these, but not good:

 

[Gyuri]

An evil comment has some truth content because of that.
The small signal J-FET transistors are obsolete products as well.

 

[Zen Mod]

well

if you count a number of his schmtcs given to Greedy Boyz , there is more made of regular and easy obtainable parts , then these made of preputium

regarding those - even small Toshibas aren't too much of a problem , even for guys living on this side of Iron Curtain

 

[buzzforb]

I agree that it is not too big of a deal. There are alternatives, including Fairchild options mentioned. I was trying to keep the P part which is what Nelson highlighted. P3 ishuge help any way you go. I even tried fakes in amp. Sounded normal, slight oscillation problem though. I am going to get all the alternatives of FQA parts and compare them to good "c" part. Should have some real info to look at.

 

[pcb121055]

However this plays out, this is a great effort on your part buzzforb. Thank you!

 

[buzzforb]

I am almost 100% sure that i have secured what i believe to be the best alternative to the 19n20C. I have one more lead on the original, but if it doesn't pan out, I would suggest FQA16n25C. I will provide links to both datasheets and I believe you will see that they are almost identical in performance.

FQA19n20c link from digikey
MOSFET N-CH 200V 21.8A TO-3P - FQA19N20C

FQA16n25c
MOSFET N-CH 250V 17.8A TO-3P - FQA16N25C

This should allow you to get datasheet direct from Digikey

 

[oiphy]

The system cannot find the path specified

 

[flg]

Well, a fine spot we are in eyy? About now, I believe it is time to look back on some comments Charles Hansen made...

 

[buzzforb]

I remember reading this conversation. Fortunately, the P channel parts are not in question and the N channel substitute seem to match the original spec'd part extremely well. Better so than the standard 19n20 part that would be next in line in the 19n family.

 

[buzzforb]

Here is a link with Nelson commenting on the original parts.

http://www.diyaudio.com/forums/pass-labs/148865-fqa12p20-fqa19n20c-discontinuation.html

 

[buzzforb]

I can get FaArichild orginal FQA16n25C parts in sealed boxes. I have some samples on the way and will provide a comparison between it and the orginal 19n20c part. If all looks good, then i will put it into an F5T and try to get some distortion numbers to compare to the article. I also will try to contact all GB members and inform them of what is happening.

 

[oiphy]

so I checked out the datasheets and I agree with you buzzforb, seems that the 25c series is a good place to start. I applaud you for youre tremendus effort with this gb.
Thanks

Stig

 

[pddjsteve]

Thanks for all the work you've put into this. I'm behind whatever the group at large decides, so far it sounds like the 16N25C is the way to go.

 

[Dr_Strangelove]

Hi buzzforb,
Also thanks for all the hard work and the substantial investment on your part!
I'll go with the part you decide.

 

[flg]

Thanks buzzforb. I agree, the 16N25C is an excellent replacement for the 19N20C. I haven't had time to do the research on Charles Hansen's suggestion of basically selecting a higher voltage complement to get the Transcunductance down to match the P part. I use a 150V part sometimes that is 20S! I think we should look for 400V N parts?