Question regarding to output power trans

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hc167

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Joined 2006
hi:

I have a question. And hope someone can help. I have a Accuphase E202 and it stopped working. What was happening is when it powered on. I can hear "pop pop" sound so I shut it off right away. Then I did the same thing again to verify that the relay is click on. I hear the click from the relay. However, it also created some smoke from around the power trans region. I have not yet inspect the amp yet. So I would inagine that the power trans are gone. And the power trans are 2SA679 and 2SC1079. What are the best substitution for those transitors since I do not expect to get the original one (30 yrs old amp, what can I expect?).
 
unclejed613

unclejed613

Member
Joined 2006
according to www.datasheetarchive.com the replacements for these are as follows:
2SA679:
2SA1028, 2SA1042, 2SA1061, 2SA1072, 2SA1097, 2SA1102, 2SA1103, 2SA1205, 2SA1265, 2SA1694, 2SA1685, 2SA1859, 2SA1866, 2SA1907, 2SA1908, 2SA1909, MJ15002

2SA1079:
2SC1584, 2SC2522, 2SD424, 2SD425, 2SD551, 2SD675A, 2SD733, MJ15001

you will probabky need to crossreference these to find which ones are intended as complements. if you look up the daa sheet for 2SC2522, it will tell you which of the 2SA numbers is it's complement. the MOT/ON devices ARE complements and are better (higher Vceo, Ic and Pd ratings with a similar beta range) devices than the originals.
 
H

hc167

Member
Joined 2006
OK, so basically, what should I get? japanese transitor or Moto/OnSemi transitor? I know there is no right or wrong answer. But is it better for japanese amp to get the japanese transitors to make it sound as close as original? Or Moto/OnSemi transitor will actually do a better job? Also, since it is very old amp. Should I replace the drivers trans also?
 
S

spind

Member
Joined 2003
Paid Member
Don't forget the MJ21193/94's or MJ21195/96's---probably the best TO-3 outputs that you can still easily buy. It sounds like there is more damage in this amp than just the outputs. The drivers on this amp are TO-66's which may be harder to find---however, I did get some from Consolidated Electronics a couple of years ago.
http://www.ceitron.com/

Good luck getting this amp going again,
Steve.
 
H

hc167

Member
Joined 2006
thanks a lot for all of your help. I do think that the only thing failure are the power transistors. because it was working a month ago. and I did a recapped about a year ago. Obviously, I am only guessing until I respect the amp. But I am thinking of getting a better sounding trans. and also replace the driver as well since I am going to work on it. I also did a google search and look like MJ21193/4 are the best in turn of the availability, and the power rating. Basically, I am just wondering if it is better to get the japanese transistors or the american transistors for a vintage japanese amp.
 
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