Problem with Bryston 3B

[kosscher]

Why would that be a problem??
These are pretty common transistors.

Ben, if you know a dual BJT replacement (mirror pinout) to the 2N5210 and 2N5087 I would deeply appreciate your advice.

 

[anatech]

Hi Ben,
I'm talking about through hole parts, not surface mount. If you know of some, that would be great. I think one manufacturer that I can't remember the name of might. The other source might be Linear Systems.

-Chris

 

[BenY]

Ben, if you know a dual BJT replacement (mirror pinout) to the 2N5210 and 2N5087 I would deeply appreciate your advice.

Are you talking about a monolithic dual BJT??

BTW, I have the 3B as well..

 

[kosscher]

Hi Ben. Yes, I mentioned dual matched transistor in one housing like the picture I posted above.
What is your 3B model, which year?
What is the DC offset on your amp? any mods you successfully implement?

 

[BenY]

I bought it used in the 90`s, I don`t have any indication of the exact production year, but I assume it was made in the mid 80`s or so. no mods done to it. in fact it`s in pieces in a box waiting for being rebuilt, if I find the time for it...


What is wrong with two sets of matched differential complementary pairs?? same part numbers as you had before?? you can tie them somehow with Al sheet metal and heat conductive epoxy.

 

[kosscher]

Nothing wrong, but we were just talking about dual matched in one housing, the matched pair is the straight way to go.

You can open a top and check the pcb Rev and production year on it.

 

[BenY]

As I wrote before, You can tie them for temperature equilibrium and minimal drift if you wrap their heads with a short strip of aluminum/copper sheet. it`s not as perfect a monolithic device, but it`s better then nothing.

 

[kosscher]

Maybe, but I also seen a different HS types
575200B00000G | Heatsink, TO-92, 60C/W, Plug-On Collar Mount | AAVID THERMALLOY

 

[BenY]

mouser has them for less...
But it`s really simple to make by yourself a strip that connects the two N devices and another strip for the two P devices and you are done. even from a soda can, if it`s made from aluminum.
See the green wrap around the pairs..

 

[kosscher]

Thank you for advice Ben, I will consider this as soon as I finish all the replacements I have to finish.

 

[anatech]

There is a better way to do that. Put a little thermal compound between them and use a short length of heat shrink to bind them together. It is a very common procedure done the world over. But the first trick is to match the transistors first. BTW, the beta checker in the meters won't work for this. Too bad.

-Chris