I found a large bag of mpsa42g in my parts bin. I used to do a lot with tubes, so they were probably for a ccs or something. Are they usefull for a preamp or buffer of some type? Does anyone have a proven schematic?
Thanks,
Chris
Thanks,
Chris
This will be moved I'm sure.
They are npn, so they can be used for the input stage of a TGM8 power amp, or a phillips 15 w - 20 w. They are 500 ma capable, or 625 mw. They are kind of high voltage, 200 so you can use them directly on the rail voltage of a power amp as long as the resistor keeps the power level in check.
Nearly anything on analog line level that has npn signal transistors could use these. The extra noise of using these instead of BC546 should be nearly inaudible. You can't buy noise figure tested BC546 phillips parts anyway, and the substitutes mostly don't quote the noise figure. 90's later Motorola and On had their processes under control IMHO.
I've found late model On Semi parts have rather extreme Hfe performance, compared to the run of the mill specs. I'm getting about 300 out of MPS8099 pnp which I used for an input stage of AX6.
They are npn, so they can be used for the input stage of a TGM8 power amp, or a phillips 15 w - 20 w. They are 500 ma capable, or 625 mw. They are kind of high voltage, 200 so you can use them directly on the rail voltage of a power amp as long as the resistor keeps the power level in check.
Nearly anything on analog line level that has npn signal transistors could use these. The extra noise of using these instead of BC546 should be nearly inaudible. You can't buy noise figure tested BC546 phillips parts anyway, and the substitutes mostly don't quote the noise figure. 90's later Motorola and On had their processes under control IMHO.
I've found late model On Semi parts have rather extreme Hfe performance, compared to the run of the mill specs. I'm getting about 300 out of MPS8099 pnp which I used for an input stage of AX6.
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I use MPSA42 for lots of things.
Differential amplifiers, VAS, constant current source, current mirror and Vbe multiplier.
They are 300 volt transistor so will work on many amps.
Its friend the MPSA92 is pretty much the same but pnp.
Differential amplifiers, VAS, constant current source, current mirror and Vbe multiplier.
They are 300 volt transistor so will work on many amps.
Its friend the MPSA92 is pretty much the same but pnp.
No logo, picture is of the back, and parts-express is not an ON distributor. 3rd party, probably not as high gain or quiet as real ON parts.
MPSA42 is much older than ON Semi, older even than PartSEXpress. These could be "vintage", Albuquerque-made, dust-of-ages, yada-yada.
And yes, they could be an odd lot from a back alley circa 2005.
And yes, they could be an odd lot from a back alley circa 2005.
Can’t go wrong or blame the supply chain for a nickel. I got a huge batch surplus made by CDIL that I’ve had absolutely no trouble with. Better Hfe and match between devices than newer Fairchild. Buy a handful, and test the vceo to be sure they are what they say they are. They’ll either take 300 volts or they won’t. If they do, stock up. If what you’re working on is super critical or for paying customers I wouldn’t use them. I have A stock and B stock for that reason. My A stock happen to be KSA44 from Mouser. The B stock A42’s I paid a lot less for.
