Positive ground booster + negative ground od together?

[zhx]

This might be a stupid question, but I've always been taught there are no stupid questions - just stupid people. So here goes:

I'm thinking of adding a booster into one of my overdrives. The overdrive is "normal ground" but the booster I'm thinking is positive ground. Any problems there? Would it work if I just put the booster circuit in there and ground it to +9v?

[smnm]

You could do it but you would need to add a second battery for the positive ground (negative supply) part, to make a bipolar power supply, like this:



then you have the issue of power switching - this shows a dpdt switch for a Craig Anderton type bipolar circuit, your + and - would be going to your separate OD and boost boards - you could use stereo switching jacks for both input and output for the 2 supplies instead of the switch.

If you haven't got room for a 2nd battery the boost will have to go in it's own box.

(edited for clarity)

[zhx]

Ok thanks smnm. Thats getting too complicated. I'll just put another booster there.

Any recommendations for a simplest possible booster for gain recovery stage? Possibly something with one transistor and fewer than 6 components total.

[soulsonic]

You could use a MOSFET gain stage. It's very simple and easy to make work.

[smnm]

... this is an easy one, I used it as a boost in one pedal, omitting the clipping diodes

[dragonfly layout;]
http://aronnelson.com/gallery/album06/ELECTRA_DISTORTION_001

if you want absolute minimum size, I think the Stratoblaster has fewer parts, but I haven't built it...

[thebigman layout:]
http://aronnelson.com/gallery/TheBigMan-Layouts/stratoblaster

the layouts gallery seems to be acting up a bit, check these later if they don't show now

[zhx]

So are you saying, that leaving the diodes out, the electra would act as a clean boost?
My plan is to put the boost circuit after the od circuit with a fixed resistor for volume pot to raise volume level, not to alter sound.

With the electra i could always put the clipping diodes behind a switch for extra dirt... hmm could work...

[smnm]

So are you saying, that leaving the diodes out, the electra would act as a clean boost?

It's not totally clean, but it is plenty loud; it does add some high end that the diodes would normally cut somewhat - increasing the value of C2 would even that out I guess. Switching in the diodes might be a good option.
I used the electra after the 1st gen Vox Distortion booster, which is quite bassy so the treblyness was useful.

[zhx]

Hmm, I don't want to alter the sound, maybe I'll just use this:
http://aronnelson.com/gallery/album143/SEKOVA_POWER_BOOSTER_VERO_001

that should be quite flat tonally.

I can omit the input cap here, right? Or do I even need the output cap at the od output before the boost?

[smnm]

I can omit the input cap here, right? Or do I even need the output cap at the od output before the boost?

I don't want to give the impression that I know any better than you, but yeah, I'd say you don't  need the input cap of the boost, but maybe it would be wise to keep the output cap of the OD, as it will stop the boost boosting the high frequencies that the output cap would be cutting.

[zhx]

I looked at big muff pi schematics, and there is a cap between the clipping circuit and the gain recovery. So I imagine you're right (at least your explanation sounds ok). And you propably know better. I' m still learning this stuff.

I'll propably put together both the blue clipper and the sekova and test both. I'll use the extra one for something else. Thanks!

[zhx]

I'll propably put together both the blue clipper and the sekova and test both.

Not the blue clipper, meant to say electra and sekova...
arrrgh, writing a master's thesis really messes with ones head, when trying to concentrate on something important like stompboxes