Fairchild interest.

[buzzforb]

To all GB members. I am going to give it one more week on the 19n20c and 19n20 parts, and then i think it will be time to talk about alternatives. The 19n20C parts are probably not going to happen, I have seen only fakes. THe standard 19n20 parts may be more likely, but kind of in the same scenario. I have found what may be a better match to the 19n20C. It is part 16n25C,also EOL. Still available to some extent, although i dont know if it is quantity great anought o meet demand. I think we need to decide which way to go with this thing. If either of these EOL life parts cannot be sourced, you have nothing but new parts. Although Nelson seems to accentuate the P parts in the article, all the newer parts available for the N channels have much greater Yfs or input capacitance compared to the 19n20C. We can discuss alternatives in a new thread. If no reasonable candidate is chosen, the best option is to go with the FQP version of the parts.

 

[6L6]

I am still in for whatever genuine parts you can source.

Do your best. It's certainly not your fault. We are all victims of the counterfeiters.

 

[bkdog]

i'm still in too - many thanks for all of your efforts Buzzforb! These parts are difficult to source.

 

[albertNL]

Thanks for your efforts, buzzforb. I will check to see how you go.

 

[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.

19n20C
http://media.digikey.com/pdf/Data Sheets/Fairchild PDFs/FQA19N20C.pdf

16n25C
http://media.digikey.com/pdf/Data Sheets/Fairchild PDFs/FQA16N25C.pdf

 

[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.

 

[studeb]

same post as in other thread.

i think the best is to try the 16n25 compare it with the "real deal" and see if you can tell them apart by ear or otherwise.
Could the oscillating "fakes" be tamed, they could have been rejects

 

[buzzforb]

Rejects or not, I am not interested. As for the sound difference, in the F5T article, Nelson shows 19n20 rather than 19n20C, which he sates in the thread linked erlier, were his chosen parts for F5 and F4. THe 19n20 shows greater differences over the 12n25c, when comp[aring to the 19n20c. It is possible the article contains a typo and this is all moot. Unless something is unusual about how the part performs, I dont think most people would ever know a different part had been used. Differences between brands, like irf249/9240 vs Fairchilds is nuanced and subtle, and if you had not heard one or the other, you wold still be getting the main sound that characterizes the F5.

 

[Horio]

Definitely give the 16n25 parts a shot, see how they measure and let us know the results. The spec sheet looks promising.

 

[labjr]

Why not just use IRF parts then?

 

[buzzforb]

LabJr,
Take a look at the link about the discontinuation of the parts. If we can get a replacement for the 19n20C, and retain the 12P, which Nelson highlights, then we have gained ground over the IRF parts, possibly. I have heard 3 different sets of transistors in my BA3. For me it goes laterals, Fairchild, IRF in order of sound. Laterals just have something special in their tone, or they and Farichild would be tied. This is all very subjective opinion and you are correct though, the IRF's will work just fine. They do have a known issue in the P channel part, as pointed out by FLG in the Hansen thread, but this may be of no consequence. I was just trying to stick to what was recommended as best as possible.

 

[buzzforb]

you guys want to add mur3020 to GB list? over 1000, we save $1 per diode.

 

[6L6]

That's a great idea. Count me in!

Edit - Looking at Mouser and Digi-Key, it looks to be a very, very good deal to do this.

 

[buzzforb]

Totally dependent on turnout. Its on spreadsheet.

 

[buzzforb]

If we get 500 of the diodes, we are talking $1.50/piece. quick signup is important because there is a 9 wk delay in maunfacturing.

 

[fdlsys]

That's a great idea. Count me in!
Edit - Looking at Mouser and Digi-Key, it looks to be a very, very good deal to do this.

At $1.5 vs. $2.8 each (in a 25 pack) @ Digikey it's a no brainer. I'm in.

 

[labjr]

Interesting diodes for power supply. Are they soft recovery, low noise?

 

[buzzforb]

Soft revovery for sure. Just know that Nelson uses them in the F5T, so most people will need them. I would assume they are low noise considering the F5T's performance.

 

[habsrock93]

Would these be a drop-in replacement for the BA2?

Thanks

Dave

 

[buzzforb]

Meaning the mosfets, yes. They are actually Nelsons chosen parts . They would need to adjusted as their Vgs vs Ids is different. We are looking at the 16n25c as a replacement for 19n25c.