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Brand of TO-3 transistors?

L

Larryhere40

Active Member
Anyone have any options on Audio Power transistors! I know they are an off brand! But are substantially cheaper! I am retired and on a budget! The Toshiba claim to be original, genuine, but they look different from my original ones! At least the printing on them! Maybe a later production?? The other manufacturer’s are also so expensive! Just wondering if anyone has used the AP transistors and there experience and don’t need the “get what you pay for” advice, it’s not always true! Lol, thanks Larry
 
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Hello. Giving the transistor number will be helpful.

Most people just avoid buying parts from ebay and buy only from trusted sources. Any other source is a gamble. If you are in a budget and you don't have money to burn, that's another reason to avoid anything that is 1% doubtful. I'd stay with the usual large distributors. I buy only from Mouser.com (no affiliation). There are other trusted sellers too.
 
If the price seems to good to be true. They generally are. Stick with name brand from a authorized distributor..;)

Digikey
Mouser
Element14(Newark/Farnell)
B+D Enterprise
Allied

to name a few.
 
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I read several topics about manufacturers which are well-known but one does NOT EVER see at Mouser, RS-online, Farnell/Element14/Newark and Digikey.

One popular brand for the audio repair business in my country is Inchange Semiconductor

At least, I found several ISC brand transistors in three of the (maybe 50 in my life) vintage audio amps I bought, always as repair replacement, and also always they were defective (again).
Usually, the "all three legs shorted" mode.....
A reputable service shop in my neighbourhood sells them, too. The shop is legit but probably they hardly know what they sell.

There are numerous questions on forums about this brand.

Myself I finally found the evidence about reliability, and it actually is in one the ISC newer datasheets! This from the BD798 transistor:

"ISC products are intended for usage in general electronic equipment. The products are not designed
for use in equipment which require specialized quality and/or reliability, or in equipment which
could have applications in hazardous environments, aerospace industry, or medical field."

Apparently this applies to all of their products. I have no reason to doubt their statement.

Therefore, a bunch of transistors I bought years ago, went in the garbage.


I am pretty sure in the industry the brands reliability figures are well known, but as a hobbyist it is so very hard to find data.
Therefore, the debate about manufacturers (and suppliers like NTE) goes on and on.

As an example, I bought some "Diotec" and "CDIL" small signal transistors, which are around 3 cents each buying 100, one day I want to find a way to test them somehow, especially for noise.
 
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gslikker said:
I read several topics about manufacturers which are well-known but one does NOT EVER see at Mouser, RS-online, Farnell/Element14/Newark and Digikey.

One popular brand for the audio repair business in my country is Inchange Semiconductor

At least, I found several ISC brand transistors in three of the (maybe 50 in my life) vintage audio amps I bought, always as repair replacement, and also always they were defective (again).
Usually, the "all three legs shorted" mode.....
A reputable service shop in my neighbourhood sells them, too. The shop is legit but probably they hardly know what they sell.

There are numerous questions on forums about this brand.

Myself I finally found the evidence about reliability, and it actually is in one the ISC newer datasheets! This from the BD798 transistor:

"ISC products are intended for usage in general electronic equipment. The products are not designed
for use in equipment which require specialized quality and/or reliability, or in equipment which
could have applications in hazardous environments, aerospace industry, or medical field."

Apparently this applies to all of their products. I have no reason to doubt their statement.

Therefore, a bunch of transistors I bought years ago, went in the garbage.


I am pretty sure in the industry the brands reliability figures are well known, but as a hobbyist it is so very hard to find data.
Therefore, the debate about manufacturers (and suppliers like NTE) goes on and on.

As an example, I bought some "Diotec" and "CDIL" small signal transistors, which are around 3 cents each buying 100, one day I want to find a way to test them somehow, especially for noise.
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Yes, kind of sucks, I’m at a point at 66, retired, and a diy guy! Love it, and also end up putting a transistor in only to have it short again! Sometimes the receiver isn’t worth the parts! When one transistor is say, 20 bucks, and the receiver calls for eight, 5 pairs for 30 bucks sounds super! I would like to do all at the same time, cause there all the same age, and the time involved in doing the repair! The cost to make one is probably a dollar! Just wish they had a decent quality product for ordinary guys like me! Haha, good luck right!
 
I buy CDIL transistors down here. They worked fine. At least they have a name on them. They are sold by a large local distributor I trust.
 
usually end up with OnSemi stuff from Mouser and Digikey. For reasons I don't understand, every order I've done in the last few years, half have come from each supplier just to make a pair. Its very annoying.
 
Larryhere40 said:
Thanks, have used the moto mj21194 and 93 that was suggested on here, then the tech said they were not right? May go with the ones you have suggested as are a better match! Thanks
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What unit were they in? They are a great sub for to-3 transistors in almost anything.
 
I have been collecting pioneer, sansui, realistic, mostly! Had a couple realistic 2000, 2080, and one 2300. I have been working on my last 3 2100d’s! All but one of the main amps is working! I put the moto in and couldn’t figure out why it didn’t work, so I went to a tech guy who goes, that won’t work ! I knew they had higher specs, but was suggested on AC they would work! Anyway after all he said, she said, I figured I would get the mj15024 and 25 which is a match! I am still learning and have to get advice even though sometimes I get a no and other time a yes! As it is I am still troubleshooting the the best I know and changing unknown stuff! I really love the mystery and have been at it over 50 years on my own,lol
 
Also, I replaced 2 bad transistors on the right amp which has 2 more original ones that still were good! I think I need to do all 4 at the same time, maybe the problem! I will try to add a picture!02E3E6B1-BF16-4A47-9ABA-5248AB938D4B.jpeg
 
I would not advise mixing transistor types in a channel like that. Seems like a problem waiting to happen.

Heck I don't even mix them within an amp. If one channel smokes and I have to re-transistor it, I compare performance to the working channel and usually change the parts in the good channel so it all matches. Unless its just something crappy enough to not justify the effort, then it gets what it gets.
 
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