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Replacements for 2SB557 and 2SD427 transistors

mauser

mauser

New Member
Hello,

I have some dead transistors in a Sherwood S-9910, and am looking for a viable new replacement, since it seems that Chinese counterfeit transistors are actually a thing. I have seen 2 different sets of transistors mentioned consistently in the forums, and am interested in the difference as it might apply to my situation. I am in the process of learning this stuff, so please bear with me if my ignorance is showing. :)

I have seen the recommended replacement for 2SB557/2SD427 are the MJ15015G/MJ15016G pair.

I have also seen the recommended replacement for 2SB557/2SD427 are the MJ21193G/MJ21194G
pair.

Can anyone shed light on the difference, or what might work best for my situation?

Thanks much!
 
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mauser said:
Hello,

I have some dead transistors in a Sherwood S-9910, and am looking for a viable new replacement, since it seems that Chinese counterfeit transistors are actually a thing. I have seen 2 different sets of transistors mentioned consistently in the forums, and am interested in the difference as it might apply to my situation. I am in the process of learning this stuff, so please bear with me if my ignorance is showing. :)

I have seen the recommended replacement for 2SB557/2SD427 are the MJ15015G/MJ15016G pair.

I have also seen the recommended replacement for 2SB557/2SD427 are the MJ21193G/MJ21194G
Click to expand...

Welcome to AK!

The biggest help you can provide to get the best answers for your question are:

  • Which circuit in the S-9910 are these transistors located? E.g. preamp, power amp, tuner, etc.
  • Which component numbers are they? E.g. TR402, Q501, etc.
  • (Extra credit) post an image of the schematic where they are used. You can find the schematic at hifiengine.com if you don't already have it.
 
dlucy said:
Welcome to AK!

The biggest help you can provide to get the best answers for your question are:

  • Which circuit in the S-9910 are these transistors located? E.g. preamp, power amp, tuner, etc.
  • Which component numbers are they? E.g. TR402, Q501, etc.
  • (Extra credit) post an image of the schematic where they are used. You can find the schematic at hifiengine.com if you don't already have it.
Click to expand...
Thanks for the quick response, here is the info you thought would be helpful.

The transistors are part of the power transmission and relay circuit.

The component numbers (per the service manual) are TR651a and TR652a

I have highlighted the affected components on the section of the attached schematic, the complete schematic was too large to upload here.

Appreciate the help!
 

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The Toshiba 2SB557 and 2SD427 are lower power versions of the popular 2SB554/2SD424 pair. On Semi MJ15024/25 pair are good replacements for the 2SB554/2SD424. The MJ15015/16 pair were considered economy transistors at one point in time but should work fine. You can't go wrong with either MJ15024/25 or MJ21193/4 pairs. Also there's not much choice any more for TO-3 xsistors everything is going the cheap plastic route.

Craig
 
If you haven't already done so, check out the ARS function on this receiver.

With 4 speakers hooked up, you simply switch to ARS on the speaker selection knob.
Supposed to work a little magic, especially on live or multi-mike recordings.
Definitely worth a listen.
 
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