nightmare transistor problem!!

fatboy · 4th November 2004, 12:23 AM

Hi Guys,

Nice forum, Ive had a good read, and found some interesting discussions.

Anyway, Ive got a power amp, with 2 tranys gone short on the output stage. They are a 2SC3856, and a 2SA1492. I am having trouble finding a supplier here in the UK, so I was wondering if you could recommend an equiv.

Ive searched the forum, and come up with a 2SC3281 and a 2SA1302 which may do the job. Can someone just confirm that it will be a straight swap, as they are quite expensive here and I dont want to buy them if they are no good.

If Im wrong, can you recommend anything else I could use.

Thanks chaps,

Martyn....

jcx · 4th November 2004, 03:06 AM

don't know if they are good subs for your original pair but onsemi (fromerly motorla) MJL2381A/1381A have superior SOA specs - less likely to blow again

Andypairo · 4th November 2004, 06:46 AM

You can't go wrong with the MJL1302/3281 , as they are similar but more rugged.

Cheers

Andrea

Elso Kwak · 4th November 2004, 07:00 AM

Quote:

Originally posted by fatboy
Hi Guys,

Nice forum, Ive had a good read, and found some interesting discussions.

Anyway, Ive got a power amp, with 2 tranys gone short on the output stage. They are a 2SC3856, and a 2SA1492. I am having trouble finding a supplier here in the UK, so I was wondering if you could recommend an equiv.

Ive searched the forum, and come up with a 2SC3281 and a 2SA1302 which may do the job. Can someone just confirm that it will be a straight swap, as they are quite expensive here and I dont want to buy them if they are no good.
If Im wrong, can you recommend anything else I could use.
Thanks chaps,
Martyn....

Hi Martyn, I second the suggestion for the Onsemi parts but you have also to replace the drivers, check all diodes, emitter resistors and the well being of the protection circuit.

richie00boy · 4th November 2004, 08:01 AM

Have you tried Profusion here in the UK? Try looking under Sanken.

Avoid the 2SC3281 and 2SA1302 as any you get will most likely be fake as they haven't been made by Sanyo for about 10 years and were replaced by 2SC5200 and 2SA1943 (which Profusion sell).

I would also replace the drivers for good measure as they are likely damaged and may fail later down the line.

fatboy · 4th November 2004, 04:35 PM

Thanks folks,

The only ones I can find here are the 2SC5200 and 2SA1943 suggested by Richie. I can only buy 10 at a time of each from Profusion, which would be a bit silly as I only need 1!

Im trying a few suppliers, who are getting in touch with a price

Thanks again for your help though.

audiopro · 4th November 2004, 05:16 PM

Try Farnell. They stock the OnSemi MJL's noted by previous posters.
The 2SA1301/2SC3281 are available from Digi-Key in the US. They're cheaper but the shipping will probably be too expensive.
These are not fakes, by the way. Toshiba, not Sanyo, makes them.

richie00boy · 4th November 2004, 05:44 PM

Yes, Toshiba not Sanyo. My haste

I think RS do the C5200 and A1943.

I cannot stress enough, take heed of Elso's and my advice to replace the drivers as well, unless you want to be doing the job twice.

4th November 2004, 12:23 AM	#1
fatboy diyAudio Member Join Date: Nov 2004 Location: south wales	nightmare transistor problem!! Hi Guys, Nice forum, Ive had a good read, and found some interesting discussions. Anyway, Ive got a power amp, with 2 tranys gone short on the output stage. They are a 2SC3856, and a 2SA1492. I am having trouble finding a supplier here in the UK, so I was wondering if you could recommend an equiv. Ive searched the forum, and come up with a 2SC3281 and a 2SA1302 which may do the job. Can someone just confirm that it will be a straight swap, as they are quite expensive here and I dont want to buy them if they are no good. If Im wrong, can you recommend anything else I could use. Thanks chaps, Martyn....

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4th November 2004, 03:06 AM	#2
jcx diyAudio Member Join Date: Feb 2003 Location: ..	don't know if they are good subs for your original pair but onsemi (fromerly motorla) MJL2381A/1381A have superior SOA specs - less likely to blow again

4th November 2004, 06:46 AM	#3
Andypairo diyAudio Member Join Date: Sep 2002 Location: near Milano , Italy	You can't go wrong with the MJL1302/3281 , as they are similar but more rugged. Cheers Andrea

4th November 2004, 08:01 AM	#5
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Have you tried Profusion here in the UK? Try looking under Sanken. Avoid the 2SC3281 and 2SA1302 as any you get will most likely be fake as they haven't been made by Sanyo for about 10 years and were replaced by 2SC5200 and 2SA1943 (which Profusion sell). I would also replace the drivers for good measure as they are likely damaged and may fail later down the line.

4th November 2004, 04:35 PM	#6
fatboy diyAudio Member Join Date: Nov 2004 Location: south wales	Thanks folks, The only ones I can find here are the 2SC5200 and 2SA1943 suggested by Richie. I can only buy 10 at a time of each from Profusion, which would be a bit silly as I only need 1! Im trying a few suppliers, who are getting in touch with a price Thanks again for your help though.

4th November 2004, 05:16 PM	#7
audiopro diyAudio Member Join Date: Feb 2004 Location: Hamilton, ON	Try Farnell. They stock the OnSemi MJL's noted by previous posters. The 2SA1301/2SC3281 are available from Digi-Key in the US. They're cheaper but the shipping will probably be too expensive. These are not fakes, by the way. Toshiba, not Sanyo, makes them.

4th November 2004, 05:44 PM	#8
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Yes, Toshiba not Sanyo. My haste I think RS do the C5200 and A1943. I cannot stress enough, take heed of Elso's and my advice to replace the drivers as well, unless you want to be doing the job twice.

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