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2012 Pre-amp: 2SA1085 Replacement

HiFi, LoFi, Tubes, Transistors, ICs, Commercial, DIY

Postby ricky_100 » Tue Sep 17, 2013 12:00 am

I am considering building the 2012 Pre-amp and have been checking availability of all the components. It appears that the 2SA1085 PNP identified for the MC/MM board is no longer available - not from RS or Farnell anyway.

Have so far been unsuccessful in identifying a potential replacement and would welcome any suggestions for this or an alternative supplier for the original 2SA1085 (if it really is still available).

Thanks
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Postby tech45leg » Tue Sep 17, 2013 12:00 am

Hi,

LittleDiode have them:

http://www.littlediode.com/product.php?productid=116315

High price to pay

Cricklewood Electronics suggests 2SA970 as a replacement:

http://www.cricklewoodelectronics.com/Cricklewood/product.php?productid=3560&cat=0&page=1

Im not sure about this though - you'd have to check with Elektor Labs...

Dave.'
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Postby thijsbeckers » Wed Sep 18, 2013 12:00 am

In Germany, Kessler Electronic offers them a lot cheaper: http://www.kessler-electronic.de/Halbleiter/Transistoren/2_SA/2SA1085_i7_460_0.htm. But shipping will add significantly, so Im not sure that's an option. Also, the styroflex capacitors cost an arm and a leg, so I would say it's not worth the trouble to search the globe for a better price if you already found them close to you.'
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Postby ricks » Tue Sep 24, 2013 12:00 am

These old Hitachi transistors came in 3 voltages, so in this case any of the 3 would work.
2SA1083, 2SA1084, 2SA1085
Attachments
2SA1083-85.pdf
(48.2 KiB) Downloaded 301 times
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Postby tech45leg » Tue Dec 03, 2013 12:00 am

Hi,

I'm also building this PreAmp and I have 12 of the 2SA1085 available to anyone who wishes to make me an offer...

Photos of my build are coming soon in a different post

Dave.
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Re: 2012 Pre-amp: 2SA1085 Replacement

Postby deltalight » Fri Sep 19, 2014 4:35 am

What gain bin i.e. <D> or <E> do you want? If <D> bin and total current does not exceed 50mA, then use Fairchild KSA992(f). Mouser has plenty for cheap.
http://www.mouser.com/ProductDetail/Fai ... Wq80Dmc%3d

Otherwise Toshiba 2SA970BU is the way to go as IC=100mA

High gain, High voltage TO-92 BJTs are getting tougher to get :(
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