Matching Transistors and Basics

[GeorgeFormanGrill]

I'm working on a Superfuzz clone, which has led me down a transistor rabbithole, which in turn has taught me I have some major gaps in my understanding of how transistors work. Some builders say the 2sc828 is a necessity, others say it doesn't matter as long as the trannie has a high gain. A few questions about the basics:

1. How do you measure the voltages of the transistors? One thread gave the exact measurements you should see in each transistor – I'd like to give matching that a shot.

http://www.diystompboxes.com/smfforum/index.php?topic=64068.0

2. What does it mean to "match" transistors? Some commentators urge you to match the trannies in the octave section...I have no idea what that means. First of all, where is the octave section (schematic attached)? Secondly, if the two parts I use are both 2sc828s, aren't they automatically matched?

Thanks for any help you can lend!
George

[micromegas]

Matching transistors means to find transistors with similar characteristics (you'll often want similar hfe or Vbe).

There are several methods.
Rob has a really well explained one on his "Hyperbolic fuzz" doc: http://rock.it-frog.com/Downloads/Docs/Hyperbolic.pdf


Octave section in the superfuzz refers to the pair of transistors that are facing each other (one has his emitter conected to R20 and the other one has it connected to C9).

[GeorgeFormanGrill]

Thanks for the reply. I'll dig into that article about matching transistors.

As for measuring voltage across the transistor, is there a good video or article I should reference to make sure I'm doing it right?

Thanks again,
George

[alanp]

https://home.comcast.net/~ijfritz/MiscProj/transmat001.pdf

Ian Fritz' article on matching transistors. He mentions Ye Olde Way, and then goes into detail on Ye Easy Way. I've got his circuit on a bit of perf lying around somewhere. It's quite thorough, even I understood it

[GeorgeFormanGrill]

Awesome. Thanks.

One other question: would this 2sc828a-r from Smallbear do the trick?

http://smallbear-electronics.mybigcommerce.com/transistor-2sc828a-r/