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How important is transistor gain (HFE) in an amplifier?

The GR 4H and BL 8K look promising. This is how the toshiba parts look like. But even these could have been faked. They have becime exceedingly profficient at replicating the original markings.

The GR 548 and Y 52B are copies made by uncertain chinese manufacturers. Dont use those.
The Y rank is not worth to buy on ebay. You may still find the KSC1815CG made by fairchild which is equivalent to the gr rank.

Keep in mind that many ebay sellers post a picture o genuine parts and then when they ship the goods you receive fakes that do not look like the photo.
I would stick to tge parts i quoted in my previous post because that seller has so far been reliable and many users -including me- purchased from them and parts were.always genuine.
 
JoseHH, I found the 2sc1345 at B+D. I sent them an email asking if they know the gain code D, E, or F. Maybe they'll write me back. Did you get a chance to look at the updated transistor image I posted earlier? Q401 & Q403 right channel differential pair have a difference in hFE of 86. Is this acceptable, or should I consider changing them? I found BC549CTA at mouser. It's only rated for 30V though. https://www.mouser.com/datasheet/2/308/BC550_D-1802078.pdf
 
I have some in the mail at the moment. I just didn't know if their gain was high enough (240?). Which is the question I posed at the start of this thread. My head is spinning. I'm having dejavu. LOL!
 
CalvinBeck said:
I have some in the mail at the moment. I just didn't know if their gain was high enough (240?). Which is the question I posed at the start of this thread. My head is spinning. I'm having dejavu. LOL!
Click to expand...

You just posted photos of 1815s and asked if they were fakes. I gave a recommendation of where to get them if you want to be sure they’re not fakes. Not sure where the disconnect is.
 
I’m sure the disconnect is with me, Gnesen. I didn’t mean any disrespect. I’m new to posting here and the last thing I want to do is offend anyone. If I did, then I apologize.
 
CalvinBeck said:
Did you get a chance to look at the updated transistor image I posted earlier?
Click to expand...
Yes.
upload_2023-2-25_10-53-33.png
Q401 need to be matched to Q403 with gain (hfe ) as close as you can. On the other channel match the gains of Q402 and Q404. Sellect a part with high gain for these positions. 500 to 600 is possible. If you 2 pairs all of them with gains of 500 +/-10 would be fine. You need to get about 20 transistors and measure their gains. Then collect in pairs. If for one channel you get for q401 and q403 :490 and 480 and for the other channel you get for q402 q404 :500 and 510, that is acceptable. Use the left over parts for q405 and q406.

For this the KSC1815Y that @Gnesen suggest are not optimum. But you can use these for Q405, Q406.

For Q401, Q402 Q403 and Q404 note that the circuit calls for gain rank F which if i remember corectly is the 600 to 1200 hfe rank. For this I suggest you use any of these:
2SC2240BL Bdent has them for 10 dollar a piece.
2SC1815BL (if you could source any genuine).
You can also consider the options i quoted in my previous post where i had linked the parts to that supplier.
 
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