My Transistors, original or copy?

[asuslover]

Hello ,
I am not questioning the authenticity of these,
but I am just curious if anyone else seen these before.
Thanks

 

[anatech]

I have seen that regulator before, but not by Linear Technology. I would have to dig out a databook from those years to check the markings to be sure.

Failing that, you would have to test them on a heat sink. Now for the big question. Where did they come from (that you know is fact)? That path and their condition might tell you something. They are extremely clean for an old part number from 1992.

 

[asuslover]

They are old indeed, I have them since 2000, not used.
These 338k were made by National, Texas Instruments , ST . But I cannot find info showing 338K( K is the key here ) was made by LT.

 

[anatech]

I've seen the "K" designation. One was a steel case and it was more expensive, good for higher current. Made by LT? No, it would have been even more expensive I bet.

 

[K-amps]

I have seen that regulator before, but not by Linear Technology. I would have to dig out a databook from those years to check the markings to be sure.

Failing that, you would have to test them on a heat sink. Now for the big question. Where did they come from (that you know is fact)? That path and their condition might tell you something. They are extremely clean for an old part number from 1992.

So nice to hear from you after all these years my friend 😊

 

[anatech]

Hey! How are you?

Good to see you too!

 

[K-amps]

Doing well. Do you still run the Adcom/Nakamichi service Business Chris?

 

[petoluk]

They are old indeed, I have them since 2000, not used.
These 338k were made by National, Texas Instruments , ST . But I cannot find info showing 338K( K is the key here ) was made by LT.

Here you go (page 2 shows the K package).

 

[anatech]

I was looking for markings information on the package. Some companies detail exactly where the markings are and the current logo at that time.

 

[asuslover]

@petoluk
Thanks but I was aware of the datasheet and the K and P packages listed there.
ST and TI are listing their lm338 metal can(k package) as LM138k/338k, but Linear Technology does not( or I cannot see it)

 

[anatech]

Hi Kanwar,
I'm glad to hear that!

Yes, I service all decent brands. I updated all the Counterpoint preamp power supplies for improved performance and reliability. You won't see my changes on the 'net. I do similar things for other equipment where improvement is possible. I don't chop and hack PCBs, but engineer changes to work with the existing circuit.
Life has been calmer and pretty good since my wife died. Sad to say I guess, I would never wish her dead.

 

[K-amps]

Kanwar is Apex Audio or something... :-D My name is Arif. Sorry to hear about your wife. :-(

 

[anatech]

Gee, sorry Arif!
I guess it has been too long ! lol!

No problem. It happens to some of us.

 

[petoluk]

@petoluk
Thanks but I was aware of the datasheet and the K and P packages listed there.
ST and TI are listing their lm338 metal can(k package) as LM138k/338k, but Linear Technology does not( or I cannot see it)

Sorry for the late reply - I wanted to take a pic of my LT regs, but that part of my stock didn't make it to our new house until today. I'm not aware of any document detailing the LT part marking convention, but - going by the actual parts I collected over the years from various trusted suppliers - the package designation letter is always printed on the case.

Hope this helps at least a bit...

 

[anatech]

Yes, you are absolutely correct - for every manufacturer in fact.

 

[asuslover]

@petoluk
What a collection you have there!
Thank you!

 

[umut1001]

Hi.I bought 1000pcs of these 2sa1408 transistors.I thought they are genuine jewels and it may have a usage for audio but i did not find.Where can it be used? Should i give them back or can sell or use them for audio applications? Any examples?

 

[K-amps]

Might be used as drivers in medium power AF amplifiers since CRT TV's don't exist much. Or maybe make an esoteric power amp with 100 of these in the output stage 🙂

 

[as_audio]

I think these can be used in a driver stage and they are genuine.

 

[umut1001]

I could only find 100pcs of 2sc3621 as complementary. Yes i do not want to give them back because they are rare good items but it costed me money so i should sell most of them 🙂
Can you give a good example which high end amp can i make with them?