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Forum Index : Electronics : Looking for AC187/AC188 transistors....

Posted: 05:38am
23 May 2026
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Grogster
Admin Group


I have an old 70's amp here(PYE 554-P radio-gram), with blown output transistor pairs on both channels, so I am looking for two each of AC187 and AC188.

I understand these are EXTREMELY rare these days, so I am happy to consider equivalents if anyone knows of sets that could be used.

They are Germanium transistors, so need to be the same type because the bias of the amp will be set for 0.2v Germanium type, and standard silicon with 0.6v would require adjusting the bias, and it appears to be fixed on this amp - no bias trimmers.



Smoke makes things work. When the smoke gets out, it stops!
 
Posted: 06:14am
23 May 2026
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Godoh
Guru

Seems to be some on ebay

AC187


AC188
 
Posted: 07:42am
23 May 2026
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Grogster
Admin Group


Yeah, but I don't trust ebay.  
Many of their parts are FAKE.

I want GENUINE replacements.

But thanks for posting!  
 
Posted: 08:03am
23 May 2026
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Revlac
Guru


Apparently there are a few forums around that play with this old gear.
Not sure if its much help, it links to another page etc.
https://www.vintage-radio.net/forum/showthread.php?t=188664
 
Posted: 10:00pm
23 May 2026
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Pete Locke
Senior Member

Michael Dranfield would be worth asking.
Cheers
Pete'
Hokitika.
 
Posted: 11:48pm
23 May 2026
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Grogster
Admin Group


Lovely, thanks.  
 
Posted: 11:46am
02 Sep 2026
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Solarnewbie
Newbie

Best I can do.
 
Posted: 11:28pm
02 Sep 2026
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InPhase
Senior Member


It's probably easier altering the bias network to use silicon than it is to source authentic working replacements.
 
Posted: 12:14am
03 Sep 2026
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Grogster
Admin Group


Thanks, guys, but the deal is done and finished, and the customer took the amp back after paying an evaluation fee that I charged to look into this issue, so I no longer have the unit.
 


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