I was looking at building douglas self's "preamplifier 2012" but i am having issues locating the 2sa1085 part for the moving coil section. I have a quote for 2.25 per transistor in 200 qnty, but only need 8.
Is anyone else having issues locating this in small qntys? anyone interested in a group buy?
Is anyone else having issues locating this in small qntys? anyone interested in a group buy?
I had not found your thread, so I started one myself, with exactly the same topic. How can a design published in 2012 use a critical transistor which becomes discontinued in 2013? Sigh... 🙁
The 2SA1085 is nothing special. Just a PNP Silicon transistor that was made obsolete in 1982.
Use a KSA992FBU. Much higher Hfe and less noise plus a hight voltage rating.
Available in singles if required.
I hold a stock of 15 at present.
Mouser part number 512-KSA992FBU at 15p each or 12p each in 10's.
Farnel, RS, ITT and others etc also keep them.
Use a KSA992FBU. Much higher Hfe and less noise plus a hight voltage rating.
Available in singles if required.
I hold a stock of 15 at present.
Mouser part number 512-KSA992FBU at 15p each or 12p each in 10's.
Farnel, RS, ITT and others etc also keep them.
Fantastic. Is this a pin-compatible replacement? I want to use a ready-made PCB (the Doug Self Elektor 2012 preamp) where I need these transistors.
KSA992
Yes, they are pin-compatible. Both are TO92 ECB pinout. Thanks! 😀
Have yet to compare the other parameters.
Available from Digikey at 21 cents each, in singles.
Yes, they are pin-compatible. Both are TO92 ECB pinout. Thanks! 😀
Have yet to compare the other parameters.
Available from Digikey at 21 cents each, in singles.
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1085 cf 992.
The voltage Vce0 is the same.
The Gain hFE in the groups is the same.
If I am reading the noise charts correctly the 1085 is quieter
The 2sa195e/c2547e is an excellent transistor pair.
Yes, it is obsolete and has become difficult to find.
The voltage Vce0 is the same.
The Gain hFE in the groups is the same.
If I am reading the noise charts correctly the 1085 is quieter
The 2sa195e/c2547e is an excellent transistor pair.
Yes, it is obsolete and has become difficult to find.
What about the BC556? Will that work well here?
Of course the transistors will have to be inserted the 'wrong way round' in the Elektor PCB. The pinout seems to be CBE here, not EBC.
Of course the transistors will have to be inserted the 'wrong way round' in the Elektor PCB. The pinout seems to be CBE here, not EBC.
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Apologies for the 3 year bump, but is that noise spec on the ksa992 correct? That seems considerably worse than the 108x series. I'd be using these for mic preamp so noise is important. Anyone measure noise on the ksa992 yet?
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I've search high and low but not finding these measurements. Searched ksa992, ksa992 noise measurement, 2sa992 etc. Must be buried in a thread I cannot find.
Care to help out?
Care to help out?
There is a NF graph on the last page here
http://www.ids-elektronik.de/421.pdf
Clearly a high Rb part for MM rather than MC
http://www.ids-elektronik.de/421.pdf
Clearly a high Rb part for MM rather than MC
2SA1085 equiv.
Replacement of this transistor can be seen here: -
KSA992FBU - FAIRCHILD SEMICONDUCTOR - Bipolar (BJT) Single Transistor, PNP, -120 V, 100 MHz, 500 mW, -50 mA, 430 hFE | Farnell element14
Replacement of this transistor can be seen here: -
KSA992FBU - FAIRCHILD SEMICONDUCTOR - Bipolar (BJT) Single Transistor, PNP, -120 V, 100 MHz, 500 mW, -50 mA, 430 hFE | Farnell element14
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