BC560B sub....?

slimecity

slimecity

Super Member
Weird question I know.

Im working on a vintage NZ-built preamp - its really nice.

Each channel has quite a few BC560B's. I have a bunch of six of these that react dramatically to freeze spray (there is characteristic noise of a degrading small tranny).

I cant find this hfe grade anywhere - thru local or overseas suppliers.....I can only find BC560C grade.

Any ideas? Please dont say Mouser or digikey as these are $60 minimum orders to ship to NZ and I'd like to keep costs down for my client, if another sub can be used. For all I know however the B grade could now be obselete? cheers!
 
avionic said:
Wondering what ? Higher Hfe is a good thing in most cases.
Click to expand...
Hmmm - OK now Im going to sound really stupid.....

The issue is in one channel of the preamp - so buy subbing with the C grade in only the one channel - I wont have one channel louder than the other channel?

lols?
 
If you found noisy BC560, replace them all now that you disassembled the unit. The rest will be in the same condition soon, and they are cheap, much cheaper than the time to disassemble the unit again. Fresh transistors will be quieter most of the times.

Alan0354 said:
People worry about not enough beta, C is definitely better. I use all C version.

If you worry about this, buy the BC556B, it's the same beta, just higher voltage transistor. Better than BC560B.

https://www.digikey.com/product-detail/en/fairchild-on-semiconductor/BC556BTA/BC556BTACT-ND/3042483
Click to expand...

Reading the old Siemens datasheet, BC556 is not the same than BC560: BC560 is lower noise and higher fT (I don't know if this 2 parameters make a difference in an audio amplifier)
http://www.alldatasheet.com/datasheet-pdf/pdf/44314/SIEMENS/BC560.html
 
elnaldo said:
If you found noisy BC560, replace them all now that you disassembled the unit. The rest will be in the same condition soon, and they are cheap, much cheaper than the time to disassemble the unit again. Fresh transistors will be quieter most of the times.



Reading the old Siemens datasheet, BC556 is not the same than BC560: BC560 is lower noise and higher fT (I don't know if this 2 parameters make a difference in an audio amplifier)
http://www.alldatasheet.com/datasheet-pdf/pdf/44314/SIEMENS/BC560.html
Click to expand...
Not for Fairchild. Never seen Seimens transistors available, I am surprise they are still in the market.
 
Alan0354 said:
Not for Fairchild. Never seen Seimens transistors available, I am surprise they are still in the market.
Click to expand...
For semiconductor parts it is called Infineon for many years already. This BC series is/was made by most big transistor manufacturers as it is as well-known as 2N3904, 2N3055, etc
 
Fairchild BC560C is still in production. You can buy Fairchild BC556C any time of the day, plenty to go around. I personally have hundreds of them. Fairchild makes no difference between 556 and 560 other than 556 is better, that can withstand higher voltage. I don't care there was Seimens/Infineon, they are not available, never seen them in Digikey or Mouser.

BC5xx are known to have high hfe, which is an asset for amplifier design. For through hole, there is no equal. I have a lot of KSA992, it is not as good, only good point is it's higher voltage.

For people that work on amps, it's good practice to stock up. I saw so many through hole transistors being obsoleted since I first design my amp. If you ever read "My Amplifier" post lately, it's all about hunting transistors. Remember, those transistors might be popular in audio world, it's only a tiny tiny little segment in the industry particular they already moved on to SMD components. It's not going to be around. You don't even know how much stock I am keeping. I just ordered and received 100 each of those big power transistors for $350 this week. I stocked like 150 of each of the driver transistors after desperate search few months ago!!! I don't even have plan to design another amp to use so many of those. I just stock up for whole life time.



EDIT: I just went on "Findchip" link in post #2 above. There is no Seimens/Infineon BC560 available. "Findchip" is one link people should keep in their bookmark, Saved my day on all the driver transistors.
 
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As the noise figures differ for same conditions, 556 is not better, but just different.

Apart from that, Farchild and ON seem to have different properties for their respective BC560 according their datasheets. So now Fairchild is ON-owned, which datasheet to use between those two???? :D:confused::dunno: I have no idea.

BTW the Siemens datasheet provides two noise graphs which might be interesting for you to save, as the others do not.
 
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On-Semi axed all their TO-92s. So going forward, you'd use the Fairchild datasheet. Sadly, from what I've seen, the On-Semi parts tended to be better.
 
Ha ha, you get what you get, it's not as if you have a choice other than Fairchild. I don't think there is equal anymore. Not just high beta, low noise, another very important thing that is very good of this transistor, low capacitance. You have need of this transistor, stock up!!!!
 
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