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-   -   NEC 2SD180 Trannys (http://www.diyaudio.com/forums/solid-state/110948-nec-2sd180-trannys.html)

dark_avenger 29th October 2007 10:50 PM

NEC 2SD180 Trannys
 
hey,

i've got an old amp that has managed to blow the 2 transisters on the right channel. just wondering if anybody knows somewhere in aus where i can find replacements

they are

NEC 2SD180
LA07


cheers.

linuxguru 30th October 2007 05:59 AM

That's an NPN 80V, 5A, 50W, TO-3 transistor, with the PNP complement 2SA626. There are many better transistor pairs available now - for instance, ON Semi MJ21194/21193 or MJ31184/31193, with much higher voltage, current and power dissipation ratings.

When replacing the transistors, check the pinout and replace both transistors (NPN and PNP) in the pair.

dark_avenger 30th October 2007 10:43 PM

thanks linuxguru the amp is class a and only has 4 of the nec transisters. not complamentry pairs.... do have a suggestion on a transister to replace them all with ?

wg_ski 31st October 2007 12:21 AM

Being a class A amplifier is enough reason to use 'overkill' trannies like the MJ21194. But if you had a cheap source for 2N3773's (or else anything with a purely thermally limited SOA at 80 volts) they'd work, too.

linuxguru 31st October 2007 07:07 AM

Since it's class-A, base-emitter charge storage effects (capacitance) don't play a significant role - so you can go with a bulletproof, monster-die tranny, even with its larger capacitance. I'd second the recommendation to go for an over-engineered, relatively-recent TO-3 like the MJ21194 or 31194 - just ensure that the beta exceeds that of the original, over the operating range.

jacco vermeulen 31st October 2007 08:51 AM

Sansui 555 ?

GK 31st October 2007 01:47 PM

2 Attachment(s)
Quote:

Originally posted by jacco vermeulen
Sansui 555 ?

jacco vermeulen 31st October 2007 01:54 PM

Bra wrencher,

you're the ace, i missed the Gas Research part.
Oz seems to be the place for high power LPG, a lot cheaper than overhere too.

(the 5PPM biggy looks impressive as well, think you bought the last of the 404's)

dark_avenger 31st October 2007 10:59 PM

cheers for all the advice i'll track down some MJ21194 and give them a go.

david

GK 1st November 2007 05:35 AM

Quote:

Originally posted by jacco vermeulen
Bra wrencher,

you're the ace, i missed the Gas Research part.
Oz seems to be the place for high power LPG, a lot cheaper than overhere too.


And here the government actually gives you a $2000 freebie grant to help towards the conversion cost, as part of an environmental initiative to encourage people to switch to a less polluting fuel.
This, in part, makes it easier for all us petrol heads to get our 30-litre-per-hundred-kilometers-fuel-guzzling 6 litre-plus hotted up V8ís converted for use as economical daily drivers on a cheap fuel.

Thatís pretty funny, I reckon.


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