Need help with AC128 transistors

[Sam Ashbrooke]

I've decided I want to get into pedal building and figured the place to start would be a fuzz face given how simple the circuit is and how easy they are to mod.

I've managed to obtain quite a few AC128 transistors from various suppliers in the hope that I can get a matched set of "good ones" but when they got here I realized I don't know what is what.

How can I tell which lead is C, which is B, and which is E?

What is the best way to test for leakage?

How do I test for "matched sets"

I know quite a bit about valves and tube amps and have built and modified several amps so I know a bit about electronics, it's just that trasistors are a new realm for me. Any help you can give me would be great.

[Albert Kreuzer]

www.geofex.com - Technology of the Fuzz Face
There is also an article about selecting the "right" transistors.

Connections of the AC128 are E-B-C clockwise when you look at it from the bottom.

Cheers,
Albert

[unparalleled]

The dot or arrow mark is the collector, the centre lead is the base on vintage germaniums.
Some like OC71 are arranged in a line, AC126 etc. are in a triangle arrangement.

[Bloodbath]

Anytime you need to know something about a transistor or IC, all you have to do is google the datasheet.

For the AC128, just google AC128 datasheet.

You will get a bunch of results. Here is one.

http://www.datasheetcatalog.org/data.../493012_DS.pdf

It shows you the pin configuration and a lot more.