Hi
Have to replace some final stage bjt, sanken sa1294/sc3263.
I do not have any idea how closely each pair should be matched, maybe it requires rhe hole 6 pairs per channel to be matched, do not know...
Any knowledge anyone?
I do see all are siries y, which Sanken state have hfe 70-140.
Also emitter resistor is 0.22 ohm 5%
Thanks
Have to replace some final stage bjt, sanken sa1294/sc3263.
I do not have any idea how closely each pair should be matched, maybe it requires rhe hole 6 pairs per channel to be matched, do not know...
Any knowledge anyone?
I do see all are siries y, which Sanken state have hfe 70-140.
Also emitter resistor is 0.22 ohm 5%
Thanks
The factory produce NPN and PNP power transistors with different Hfe rank, in normal case, the same batch transistors Hfe are very close, but NPN and PNP will be different, so that NPN and PNP power transistors are very hard to match with each other, it need to test a lot of transistors to do the NPN to PNP match.
Normal we can only do match among the same batch of NPN / PNP transistors, so that they are no NPN to PNP matched.
If you cannot do the match, you just buy the same batch transistors for replacement, for more safe to balance these not matched transistors, you can change all the emitter resistors to 0.33 ohm or 0.47 ohm.
Normal we can only do match among the same batch of NPN / PNP transistors, so that they are no NPN to PNP matched.
If you cannot do the match, you just buy the same batch transistors for replacement, for more safe to balance these not matched transistors, you can change all the emitter resistors to 0.33 ohm or 0.47 ohm.
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Thanks for the reply.
How tight should the matching be?
Which is more important/accurate measurment: hfe, Vbe, voltage drop on emmiter resistor?
How tight should the matching be?
Which is more important/accurate measurment: hfe, Vbe, voltage drop on emmiter resistor?
Matching suppose in perfect matched, but in practice it depends on how many transistors for you to do the selection, when you test all your batch transistors and you will know how tight you can do the matching.
They are all important, I think hfe is more important, others let the emmiter resistors to balance them.
Hi there,
Have a look here: you will find quite some info here.
Guidelines: Vbe Within 1mV @ bias current, Hfe within 10%.
https://www.diyaudio.com/forums/sol...ransistors-class-tou-match-2.html#post6159938