Why match transistors?

JoeBob · 22nd May 2002, 07:11 PM

Alright, I know that matching them is obviously the better thing to do, but my next project uses quite a few small signal transistors and I was wondering if I really have to match them all. What's the difference really between matching them and just selecting at random? Basically I'm a lazy guy and all I want to know is will **** break if I don't match them heh...

peranders · 22nd May 2002, 08:12 PM

You can use BC847BS and BC857BS. They are very cheap but small. Works like separate BC847 and the matching is fair, remember the price! The big advantage is temperature matching. I have tested them in my monster overkill phono amp and they worked very well.

To answer your question: When you use differential stages and currrent mirrors it can be a good idea to match or use matched transistors but I would say it's more important to keep the temperature equal. I would also say it's more important in diff stages to match.

http://home5.swipnet.se/~w-50719/hif...l#Anchor-47857

Nelson Pass · 22nd May 2002, 08:36 PM

depends on the project. With Bipolar
devices you can probably get away with
it regardless.

JoeBob · 22nd May 2002, 08:54 PM

Ah, this is great news for a lazy guy like me, time to start building then...

22nd May 2002, 07:11 PM	#1
JoeBob diyAudio Member Join Date: Nov 2001 Location: Montreal, Canada	Why match transistors? Alright, I know that matching them is obviously the better thing to do, but my next project uses quite a few small signal transistors and I was wondering if I really have to match them all. What's the difference really between matching them and just selecting at random? Basically I'm a lazy guy and all I want to know is will **** break if I don't match them heh...

22nd May 2002, 08:12 PM	#2
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	You can use BC847BS and BC857BS. They are very cheap but small. Works like separate BC847 and the matching is fair, remember the price! The big advantage is temperature matching. I have tested them in my monster overkill phono amp and they worked very well. To answer your question: When you use differential stages and currrent mirrors it can be a good idea to match or use matched transistors but I would say it's more important to keep the temperature equal. I would also say it's more important in diff stages to match. http://home5.swipnet.se/~w-50719/hif...l#Anchor-47857 __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread

22nd May 2002, 08:54 PM	#4
JoeBob diyAudio Member Join Date: Nov 2001 Location: Montreal, Canada	Thanks.. Ah, this is great news for a lazy guy like me, time to start building then...

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22nd May 2002, 08:36 PM	#3
Nelson Pass The one and only Join Date: Mar 2001	depends on the project. With Bipolar devices you can probably get away with it regardless.

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