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TIP142 and TIP147 TO 3 equivalent?

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freaker_pz

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Hi!

I'm new here.

I have audio amplifier with TIP142 and TIP147 transistors... I want to replace them with something from TO 3 series... Any suggestions?
 
Perhaps?, depends if you can find any high power darlingtons in TO3.

The reason for asking why is that when people don't give their reasons, it usually turns out they are trying to do something pointless or impossible.
 
Without knowing what you are trying to do, any recommendations would be wrong almost surely. Why should we waste our time trying to guess what you are up to?
 
I told ya in my first post - these are transistors in my QUAD 405 Amplifier.... I want to change them because the TIPs aren't working properly....

Please, if you aren't going to give an example don't write/....
 
I told ya in my first post - these are transistors in my QUAD 405 Amplifier.... I want to change them because the TIPs aren't working properly....

You said nothing of the kind, you've never mentioned Quad or 405 before this post.

This is why I asked why you were asking, and (as usual with vague requests) your request is completely wrong.

The Quad 405 doesn't use darlington output transistors, the mkI version used BDY77's, and the mkII used 17556's - these are all single NPN devices.

You can't replace them with darlingtons.

I suggest you have a look at **broken link removed** which should tell you all you need to know.
 
take a look at this: 200W Amp
pay attention on T11 and T12 ;)

....partlist....
Т11 – КТ827А (or TIP142) (Darlington)
Т12 – КТ825Г (2Т825A or TIP147) (Darlington)

My QUAD is this version
 
take a look at this: 200W Amp
pay attention on T11 and T12 ;)

....partlist....
Т11 – КТ827А (or TIP142) (Darlington)
Т12 – КТ825Г (2Т825A or TIP147) (Darlington)

My QUAD is this version

Thats not a Quad 405 :D it's not a 'Quad' anything.

As it's designed for the TIP142 and TIP147 I would suggest you stick to them, if they aren't working you have a problem elsewhere - changing the transistors for different types isn't going to help at all.

200W is also rather optimistic as well :D you get about 60W out of a pair of TIP142/147's.

Bit difficult to know what the article says, but I'm dubious about it's quality compared to the real 405's, still a highly rated amp today.
 
yes, i've read something about this version of 'quad'.....
At first it all was well but after that the output transistors went down.... Anyway, accodring to you, there's no way of changing these transistors? Beacause I really want to change them
 
yes, i've read something about this version of 'quad'.....
At first it all was well but after that the output transistors went down.... Anyway, accodring to you, there's no way of changing these transistors? Beacause I really want to change them

Like I said originally, they are darlington power transistors, NPN and PNP, try and find some similar rated TO3 ones if you want.

But if all was well until they failed, and replacing them hasn't cured it - then something else has been killed as well - it's rare that only the output's die.

Do you know why they died?, were they on large heatsinks?, what were you feeding?, how heavily were you driving it?.
 
there were no radiators at all :D that's the raeason....
what about using 2N3773 instead of TIP147 or TIP 142?

It's not a darlington, and it's only NPN - you need an NPN darlington, and a PNP darlington.

2N3773 would probably be fine in a real 405 though.

But the TIP's are really good transistors, repair the amp correctly, mount them on a proper heatsink and they will be fine - if you get TO3 transistors you still require a proper heatsink, and TO3's are more trouble to mount.
 
I have heatsink for TO3s :) The problem for me is to find one for the TIPs...... Maybe that's one of the reasons for my wish to change them... I know it's stupid but I really want it :D Please, recommend me replacements for the TIPs
 
My guess is that knowing as little as you do about transistor circuits the TO3's will also tank quickly as well. Darlington power transistors have very high gain and are easy to overdrive. The existing biasing scheme for the TIPs may be off the mark for the TO3s. Even if you are a terriffic technician and can do a bang up job of mounting and heatsinking the results will probasbly be most disappointing.
 
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