VooDoo Lab OD

[Gilles C]

Thanks for the corrections.

It gives a nice set of things to experiment. I always thought that it would gave been a nice standard circuit that could be use for experimentation, bnevercame back to it.

Thanks to oldrocker (and the others) for having bring it back.

Gilles

[theman]

I believe the reason you'd tie the diodes to the divider instead of ground is because you want the same DC potential on both sides of the diodes.  This circuit doesn't have a decoupling cap on the output of the first opamp, so the tops of the diodes are seeing 4.5vdc.  You'd want the other side of the diodes to see that same potential.   I believe the other pedals that have diodes to ground have decoupling caps off the outputs of the opamps.  but it's just a theory...


PaulC

paul is right ... check out the other hard clipping diode designs. if the diodes go to ground (like in a rat), then they will have a decoupling cap before them. the dc voltage across the diodes should be balanced.  it's the ac signal that you want affected.

[WGTP]

I'm not sure if it would mess up what is going on with the diodes, but could you use R8 - 10K and make a stupidly simple tone control?   

[JHS]

The stupidly simple tone control is a good idea and the cap can be connected to VREF or ground (less dynamic).
I think A 10k pot with 5,1k at the ends of the pot to limit the swing and a 1-2,2n will work fine.

JHS

[smank]

Instead of the stupidly simple tone control you can use a pot+cap from the R8/pin 5 to ground.
100K (linear or better reverse log) + 2,2-3,3n will work fine.
In this way, when the pot is set to maximum, there is around no influence on the original sound.

[WGTP]

This would seem to be an ideal circuit to use this for clipping diodes:

http://www.diystompboxes.com/analogalchemy/misc/softclip.html

[WGTP]

I guess you could use a SSTC at both 10K resistors for a 12db/oct. roll off.  Might have to alter some other values to make it brighter, so that the treble control would be used.   

[WGTP]

Would the difference in sound between the diodes going to V1/2 and Ground be worth a switch?   

[kusi]

hi,

if you would switch the clipping-diodes to ground, you have to add a decoupling-cap after the first opamp-stage. if not, you have a DC-offset around 4,5V at the diodes...! (don`t forget a bias-resistor for the second stage if you add a decoupling-cap!)

regards,
markus

[WGTP]

I guess we could switch the 10uf cap in/out as well, again, it the sound is different enough to make it worth while.

[smank]

Instead of the classical 1N4148 pair on my Shredmaster project I've installed a 3mm red LED + a germanium diode clipping network: it sounds different, with sligth more mids, due to the asymmetrical distortion, but a bit to the components characteristics too.
The Voodoo Lab Overdrive could be another circuit to try this network.

[WGTP]

So does this clipping arrangement with the diodes going to V/ref produce softer clipping than the standard diodes to ground arrangement?   

[Nashtir]

Hi guys, could someone post again the layout and pcb?the link seems to be broken!Anyway is this pedal the sparkle od??

[MartyMart]

Here's my Vero layout from 2005 :
http://aronnelson.com/gallery/Martys-layouts-and-photos/VooDoo_Labs_OD?full=1

And a sound sample :
http://aronnelson.com/userfiles/VooDooLabsOD.mp3

Forum seems "sluggish" today, so give it some time !!

Marty.

[Gilles C]

The pcb layout will be back soon. Sunday and/or maybe Monday, they are/were moving the server where my site is.

Having Marty's stripboard layout makes it no excuse to try it, no matter the type of building you like. 

Gilles