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2SA798 opinions

rhodus said:
I wonder if anyone has done any "bench testing" of them if that's possible.
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Yes, it is possible if someone wanted to do a thorough voltage, current, and pulse test. But why waste the time when it is so easy to use KSA992 and heat shrink them together? Plus you wouldn't know the consistency or QC of those counterfeits. They tend to throw in any old die and slap a label on them.
xraytonyb has a few videos on transistor types and their effects in circuits. Some include counterfeits. This is just one of them...
 
blhagstrom said:
I wouldn't trust them.

We know how to gain match a pair of KSA992 so why not do what we know works?
Unless you are not set up to gain match KSA992s. I suppose there is a market for someone to sell matched ones for that purpose.
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Even a Peak DCA55 or DCA75 will get you "close enough". I have pulled many a 798 type (dual) that were off by over 100 hFE each die with vBE quite a difference, and still "worked". Not that well sometimes, but smoke wasn't puffing out. :D 1% or less is ideal, 2% still dandy, but 5% or less will still be "good enough" and not cause audible issues.
 
I checked the Peak readings with a big curve tracer I had access to once. The Peak was just as accurate or better. Reading the analog curve tracer curve is an eye test at best to get accurate readings.
 
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