Re: Fender Bassman and Sunn 200s preamp pedals.

Posted by SeaWitch on
URL: http://guitar-fx-layouts.238.s1.nabble.com/Fender-Bassman-and-Sunn-200s-preamp-pedals-tp25184p44855.html

Frank_NH wrote

According to my JFET spreadsheet, for a 1.5K source resistor, the optimal drain resistance for a "typical" 2N5457 is only about 7K!  So a 100K trimmer is overkill.  You can use a 20K (or even a 10K).  Try to get about 4.5V - 5V on both drains.

If I add a voltage doubler to either of these builds, is there a general rule as to what voltage I should re-bias the drains on the 2N5457's?

For a 9V source, the drains should be 4.5V - 5V, what should they be with a 18V source?

Thanks!