Re: Drunk Beaver OverBooster (A Boss FA-1 Fet on crack)

Posted by Neil mcNasty on
URL: http://guitar-fx-layouts.238.s1.nabble.com/Drunk-Beaver-OverBooster-A-Boss-FA-1-Fet-on-crack-tp50508p50701.html

I see one very obvious mistake; The JFet transistor has the wrong pinout configuration.
If you use sockets, you can bend the legs (add heat shrink to avoid contact between legs when bending them), but otherwise you'll have to resolder it.
You could also try to switch it with another JFet that has the DGS configuration as well (MPF102 is often used as alternative to 2N5457). That way you will not need to redo the layout, unless there are other errors discovered.
The circuit might not be too picky about which transistor you use, and part numbers are not that important as getting it up and running. Most part are inter-changable, and this specially goes for transistors. A lot of fun results can be discovered by doing stuff "wrong". (Devi Ever/Death By Audio/Dwarfcraft Devices are perfect examples)

On your layout: The JFet is confugured DGS (top to bottom) which is how MPF102's and SK30AY are configured. But this is not the case with 2N5457, which should be configured: DSG

This is the case for most JFet's and it is a good practice to always check JFet pinouts. They can be a pest and it is easy to forget to check, causing a lot of headache because you are looking for errors everywhere else (like I have done a lot)

It is one of the most common error in layouts containing JFet's, and I've noticed that this error is circulating frequently on the newer layouts posted here recently.
It it is a subject worth some attention I guess, since there are probably a lot of new people here that could benefit with a little input and engagement from the more experienced users.

Some pedal builders shun JFet's like the plague due to the Bias issue and poor noise-floor (worst in Mosfet) alongside the variations in pin configuration. But who the hell cares about a poor noise-floor in a distortion pedal? That is often what we want! That is why I love Germanium! Crappy Quality making wonderful sound!

Anyway... Just wanted to inform you about the error, and add some information that I hope someone will find usefull...
Great to see increased activity lately!
Keep on chucking out those layouts! It is highly appreciated!
Cheers!