Hi Mr Electro,
The first place to start is by looking at the manufacturer's data sheet. Do the markings agree with spec? Does the date code make sense?
Then of course there is the question ... where did you buy it? If you got it cheap off Ebay or the other usual suspects ... well then who knows? If it is new manufacturer the answer is no for discontinued products.
If the part should be new (you got it through proper distribution), you can test it to see if it agrees with published specs. Don't bother if the markings don't agree.
This is what we do. So when you pop up and ask "is this real?", at least one of us is going through those steps. This thread is really about educating people to be able to do this on their own. If they have examined the part, then post.
The first place to start is by looking at the manufacturer's data sheet. Do the markings agree with spec? Does the date code make sense?
Then of course there is the question ... where did you buy it? If you got it cheap off Ebay or the other usual suspects ... well then who knows? If it is new manufacturer the answer is no for discontinued products.
If the part should be new (you got it through proper distribution), you can test it to see if it agrees with published specs. Don't bother if the markings don't agree.
This is what we do. So when you pop up and ask "is this real?", at least one of us is going through those steps. This thread is really about educating people to be able to do this on their own. If they have examined the part, then post.
I apologize, you are right, I should provide more information about it, I got the material from a trusted supplier, but when searching for the ST company datasheet I did not find that it is manufactured in this type of encapsulation, so I thought someone from here I could easily recognize if it was counterfeiting or not, or have some information if ST outsources the manufacturing to another company. I took measurements and it seemed to behave well, but the encapsulation caught my attention, Regards
@Mr Electro , Looking at this post, and I don't know if these transistors are genuine, but I do really wonder where in audio do you use high voltage switcher??? I'm really curious.
I have a bag of NOS CRT television transistors, linear high voltage mid current parts and don't know what to do with them... Feel sorry to put them in a bin..
I have a bag of NOS CRT television transistors, linear high voltage mid current parts and don't know what to do with them... Feel sorry to put them in a bin..
Hi Mr Electro,
If they behave as expected and you bought them through proper channels, I would trust them. If they fail when they shouldn't, go after the place you bought them.
I would measure electrode capacitances and beta as quick checks.
Hi Drbulj,
Some English manufactured amplifiers used these as outputs. Maybe others, but I have direct experience with amplifiers that were designed and manufactured with those parts.
If they behave as expected and you bought them through proper channels, I would trust them. If they fail when they shouldn't, go after the place you bought them.
I would measure electrode capacitances and beta as quick checks.
Hi Drbulj,
Some English manufactured amplifiers used these as outputs. Maybe others, but I have direct experience with amplifiers that were designed and manufactured with those parts.
Hello,
Please throw some links or opinions to this. On specs these old TV transistors look linear, but they are not made for audio, and specs don't show enough useful details .....
Thanks,
Drazen
Hi Drazen,
I agree with you. However the equipment was designed with them.
I was the Canadian Service Manager for Creek and Cyrus, I think it was Creek that used them. At any rate, I am not free to release the service information to prove my point. These transistors were also supplied as spares from the factory. I repaired a few amplifiers using these transistors.
I will only substitute transistors if the originals are NLA, or if the parts clearly cannot withstand the circuit conditions. The engineers designed the products with these, and they stabilized the design with them. Why would I second guess them, and have to stabilize the amplifier design again without good reason?
-Chris
I agree with you. However the equipment was designed with them.
I was the Canadian Service Manager for Creek and Cyrus, I think it was Creek that used them. At any rate, I am not free to release the service information to prove my point. These transistors were also supplied as spares from the factory. I repaired a few amplifiers using these transistors.
I will only substitute transistors if the originals are NLA, or if the parts clearly cannot withstand the circuit conditions. The engineers designed the products with these, and they stabilized the design with them. Why would I second guess them, and have to stabilize the amplifier design again without good reason?
-Chris
Hello Drbulj, these transistors are used in some outputs and also sources, at the moment I am trying to use them in a self-oscillating source that works at about 30 khz to replace transistor2SC4140, which unfortunately I cannot obtain, I am also looking for a replacement for mosfet2SK3603-01MR, but so far without result, it's difficult to get original material where I live, but I do my best. Don't throw away your transistors, they can be used in some applications! what code are they? Greetings colleagues
Hi Mr Electro,
If you are building a one-off, the mosfet may be found in some PC computer power supplies. If you are looking for a steady supply of new parts, you'll be forced to use whatever your suppliers have. Don't use "not recommended for new designs" type parts as they are nearing end of life (EOL).
If you are building a one-off, the mosfet may be found in some PC computer power supplies. If you are looking for a steady supply of new parts, you'll be forced to use whatever your suppliers have. Don't use "not recommended for new designs" type parts as they are nearing end of life (EOL).
BUV48 would normally be in TO-247, not TO-3P. A TO-3P version would be BUW48. It does NOT look like an ST lead frame. The back side is quite unique - going back all the way to the TO-218 when it was just SGS. The corners are beveled off on the TO-218/3P, but the notches were always there.
Attachments
It's actually worse than that. For a couple dollars, you can lose hundreds of dollars in parts and many hours of labour. All for the sake of a couple dollars.
I just looked at a three channel amplifier with a fault in the centre channel. Upon looking at it, I discovered the left and right channels were previously worked on by two different shops. Each repair was an epic fail that simply hadn't blown - yet. One channel's DC offset was -141 mV, couldn't adjust it down far enough (probably bad diff pair - but it uses mosfets), the other channel had a new Mosfet drawing nearly 3x the current of the others. 10 outputs per channel. Both shops were negligent in releasing this amplifier and now I have to repair all three channels (if the customer accepts the estimate). I don't know if the parts used were legit or not yet, I haven't taken it right apart.
It would take a little time to test and match the new parts, and now the customer has to pay to have everything done again. All because techs were lazy or simply stupid. I am so sick of this.
So yeah. Saving a couple dollars can cost others several hundred. Way to go! I see this very commonly, and "fake parts" are very common in repairs that failed again. Poor workmanship goes hand in hand with unsuitable parts.
I just looked at a three channel amplifier with a fault in the centre channel. Upon looking at it, I discovered the left and right channels were previously worked on by two different shops. Each repair was an epic fail that simply hadn't blown - yet. One channel's DC offset was -141 mV, couldn't adjust it down far enough (probably bad diff pair - but it uses mosfets), the other channel had a new Mosfet drawing nearly 3x the current of the others. 10 outputs per channel. Both shops were negligent in releasing this amplifier and now I have to repair all three channels (if the customer accepts the estimate). I don't know if the parts used were legit or not yet, I haven't taken it right apart.
It would take a little time to test and match the new parts, and now the customer has to pay to have everything done again. All because techs were lazy or simply stupid. I am so sick of this.
So yeah. Saving a couple dollars can cost others several hundred. Way to go! I see this very commonly, and "fake parts" are very common in repairs that failed again. Poor workmanship goes hand in hand with unsuitable parts.
Yes, I know. I'm not a repair tech, but as it is, I wouldn't want to take in repair work. Too many headaches and not worth it. Not interested in fixing broken tracks, fixing a poor repair, etc. Most people dont want to pay several hundred dollars for a refurb, unless its something really valuable. I'd rather buy old gear, refurbish, and sell at my leisure.
Hi,
I listed bin of old HV transistors that I have , admin moved it here, see if there is something that fits your purpose:
https://www.diyaudio.com/community/...exclude-shipping-handling.413903/post-7709579
That package is all wrong, but the innards dont look like what they put in fakes. It looks like a real OnSemi package. Markings do look like ST. My guess is it’s a re-mark. What’s the hFE on these things like? Real BUV/W48’s are pretty low (20 maybe 30) but linear. If it measures 50, 100 it’s probably really another type being passed off as BUV48. It’s just as common as outright counterfeiting with 2N3055 (or smaller) dies in them - and white goop.
I bought a pair of Quad 606 clones: https://www.ebay.com/itm/185982898419
it uses 2SD718 output transistors.
Thought I ask before I start to build.Could the 2SD718 be fake?
Anyone else built this one?
it uses 2SD718 output transistors.
Thought I ask before I start to build.Could the 2SD718 be fake?
Anyone else built this one?