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View Full Version : replacement for 2N3819 transistor?


Carstens
05-21-2011, 03:26 PM
Anyone familiar with these JFET transistors. They are 10mA 25v.

I was wondering whether there is another similar JFET that would have a higher output to use in a distortion pedal that seems to be low in overall volume?

candletears7
05-21-2011, 03:30 PM
Just google the equivalent, or the datasheet, which will tell you the gain and pinout. J201's get a lot of love for boost/clipping applications in dirt pedals.

8len8
05-21-2011, 04:15 PM
The transistor itself is not likely to be directly impacting the volume. The feedback network (resistors) around the transistor set to final volume. You'll need to tweak them.

Carstens
05-21-2011, 04:51 PM
i'll take a look. not necessarily the transistor bias resistors to ground, but others around that circuit?

thanks for the input.

CodeMonk
05-21-2011, 06:31 PM
Go here: http://www.datasheetarchive.com/
Enter the part, then scroll to the bottom of the page where it says "Cross Reference".
Might be a good idea to get the datasheet as well.
With VERY FEW exceptions, I won't use a part if I can't find a datasheet for it.

BTW...if anyone can find a datasheet for a 2N440, I would appreciate it. And no, I didn't miss a number there.

8len8
05-21-2011, 06:46 PM
i'll take a look. not necessarily the transistor bias resistors to ground, but others around that circuit?

thanks for the input.

It might not be that simple. If it was a simple "common source" FET amp then I'd say look for one or more resistors between the FET drain and the gate. There's only 2 issues:

1- Most pedals have multi-stage complex circuits with more than 1 feedback loop.
2- The stuff I talk about will likely change the distortion, maybe not just the volume.

You should really take the pedal to a tech who knows that pedal...