Re: 27v Split n' Boost

Posted by MAO on
URL: http://guitar-fx-layouts.238.s1.nabble.com/27v-Split-n-Boost-tp44386p44432.html

All right, give this one a try.

This is the smallest, bare bones version I could come up with that may actually do the trick.

Again, assuming you will be tapping off a clean 9v supply from the effect as there is no DC filtering included other than for the Vb. Also, it would be good if the effect has it's own volume control in case you want to mix in a lower clean signal.  

To save space, hopefully you can lay down the bottom 10u, and tuck it below the IC. The 10u near the top can be replaced with a MLCC, probably anything above 1u will be fine.

The 2u2 MLCCs can be a smaller value if you don't have any, but I'd probably keep them at or above 1u. Or you can use electrolytics with the + side towards the IC, but no room to lay them down so MLCC will keep the size down.  

Either use 1/8 watt resistors for the light blue 100k and 1k, or bend one of the legs back underneath for 1/4 watt resistors, or just stand them up a bit.
 
The jfet can be just about anything with a DGS pinout.

D4 is optional. If you omit it, don't make the cut underneath it.

Opamp is TL072 or similar.  Try a 5532 if you already have one.  
 
The max available gain for the strait signal is 11x (20dB). If you need more boost for the clean signal, lower the value of the 10k resistor, start with 6k8. If you don't need 20dB, increase the 10k up to 20k or 22k, or you can lower the pot value to 50k.

Good luck!