Voodoo Lab Overdrive

gaussmarkov · January 11, 2008, 05:14:25 PM

The Voodoo Lab Overdrive belongs to the same family as the IC-Based Overdrive described in this project. Here is my version of the schematic, with some notes to get you started on possible mods:

And here is the part list:

Part Value Library

C1 10n gm-caps-film-box
C2 220p gm-caps-film-box
C3 100n gm-caps-film-box
C4 1n gm-caps-film-box
C5 220p gm-caps-film-box
C6 2.2u gm-caps-electro-pol
C7 2.2u gm-caps-electro-pol
C8 100u gm-caps-electro-pol
C9 100n gm-caps-film-box
C10 100u gm-caps-electro-pol
D1 1N4148 gm-diodes
D2 1N4148 gm-diodes
D3 1N4001 gm-diodes
IC1 TL072P gm-ics
R1 2.2M gm-resistors
R2 10K gm-resistors
R3 470K gm-resistors
R4 470K gm-resistors
R5 47K gm-resistors
R6 10K gm-resistors
R7 10K gm-resistors
R8 150K gm-resistors
R9 47K gm-resistors
R10 150 gm-resistors
R11 47K gm-resistors
R12 47K gm-resistors
R13 47 gm-resistors
GAIN 500K-RA gm-pots
LEVEL 100K-A gm-pots

If you would like to try playing around with this circuit, here is another breadboard layout to get you started:

all the best, gm

gaussmarkov · January 11, 2008, 05:38:03 PM

another mod to consider is increasing C5 from 220p up to 680p, 1n, or even 10n. this will lower the corner frequency of a low pass filter that will smooth out the sound of heavy clipping. see Op Amps 4: Divided Negative Feedback for more info.

biggy boy · March 28, 2009, 06:17:30 PM

Thanks GM
I snagged the eagle layout from your site.

I'm thinking of building it but not sure if will be good for metal type distortion, Black Sabbath, Mega Death........ style.

Glen

BAARON · March 30, 2009, 12:56:18 AM

Quote from: biggy boy on March 28, 2009, 06:17:30 PM
I'm thinking of building it but not sure if will be good for metal type distortion, Black Sabbath, Mega Death........ style.

Glen

Probably not. The Fulltone OCD is based on this, and it's a far cry from being classic metal. Check out some OCD demos to get an idea of what it might be like. I personally have issues with the voicing of the OCD, but lots of other people seem to like it.

biggy boy · March 30, 2009, 07:59:51 AM

Quote from: BAARON on March 30, 2009, 12:56:18 AM
Quote from: biggy boy on March 28, 2009, 06:17:30 PM
I'm thinking of building it but not sure if will be good for metal type distortion, Black Sabbath, Mega Death........ style.

Glen

Probably not. The Fulltone OCD is based on this, and it's a far cry from being classic metal. Check out some OCD demos to get an idea of what it might be like. I personally have issues with the voicing of the OCD, but lots of other people seem to like it.

Ok thanks for the heads up!!

Glen

knealebrown · March 25, 2010, 06:52:42 PM

Hey guys just built this and i cant get it to work.

-Checked correct polarity of all components e.g diodes, electro caps
-Changed the opamp and pots
-re soldered everything
-checked for solder bridges
-changed the op amp for a 558, still nothing.
-checked all cap, resistor and diode values

did anybody else have any problems with this build?

im getting audio out but its clean and the gain pot doesnt give any effect but the volume works fine.

any suggestions?

Thanks

biggy boy · March 25, 2010, 08:06:04 PM

Do you have the Ic in the right way (direction)?
Is there any solder bridges maybe? shorting out between two traces.

knealebrown · March 25, 2010, 08:38:55 PM

yeah i have checked those simple things so many times $:-\$

measured across the pots just now and got good readings 0>500k on the gain and 0>100k on the volume so its not them. Thought i had solved it by identifying a wrong value resistor but when i put the correct one in it didnt make any difference. Will post the op amp voltages 2moro or sat when i get time. Until then any other suggestions?

Thanks for your time

knealebrown · March 25, 2010, 08:43:25 PM

Quote from: knealebrown on March 25, 2010, 08:38:55 PM
yeah i have checked those simple things so many times $:-\$

measured across the pots just now and got good readings 0>500k on the gain and 0>100k on the volume so its not them. Thought i had solved it by identifying a wrong value resistor but when i put the correct one in it didnt make any difference. Will post the op amp voltages 2moro or sat when i get time. Until then any other suggestions?

Thanks for your time

my opamp is a tl072cp is that any different to the tl072p? is this my mistake?

kymar · April 01, 2010, 12:05:57 PM

Quote from: knealebrown on March 25, 2010, 06:52:42 PM
Hey guys just built this and i cant get it to work.

-Checked correct polarity of all components e.g diodes, electro caps
-Changed the opamp and pots
-re soldered everything
-checked for solder bridges
-changed the op amp for a 558, still nothing.
-checked all cap, resistor and diode values

did anybody else have any problems with this build?

im getting audio out but its clean and the gain pot doesnt give any effect but the volume works fine.

any suggestions?

Thanks

I have the same problem! It sound not bad but it has small amount of drive

knealebrown · April 01, 2010, 02:37:03 PM

dude im kinnda glad your in the same boat as me. Atleast your getting some overdrive all im getting is a clean boost. My gain pot does nothing.

can anyone who has built this before give us some information? was it a straight forward build? or did you have problems?

thanks

kymar · April 02, 2010, 03:57:53 AM

my voltages are
pin volts
1 4,54
2 4,55
3 4,22 at full drive; 4,3 at min drive
4 0 - Gr
5 4,53
6 4,54
7 4,54
8 9,05 power in

at some schematics there are no R5 47K res, maybe remove it?

kymar · April 04, 2010, 08:31:11 AM

I change drive pot to B500K and R5 to 2k2 it became much better. But not too much drive and sustain.

supertulli · March 02, 2011, 07:45:51 PM

Hello !

I'm building this baby, and got into some mods I like. However, as I'm from Portugal, I'm having trouble finding a 500k-RA pot, and as I read a couple of times the article on "The secret live of pots" by R. G. Keen, I believe that in this case one can not turn a linear pot into a RA one, for putting a resistor in parallel with CCW and the wiper is useless. Can anyone tell me if my assumption is right?!?!?

Cheers, Pedro.

supertulli · January 15, 2012, 02:27:40 PM

Hi there!

This year i've built 2 of these using a layout for stripboard of my own, which is working. It has also a tone stack. I would like to share but can't seem to post images. Help!?

avianoguitarist · January 19, 2012, 12:30:44 AM

Quote from: supertulli on January 15, 2012, 02:27:40 PM
Hi there!

This year i've built 2 of these using a layout for stripboard of my own, which is working. It has also a tone stack. I would like to share but can't seem to post images. Help!?

To post pics, you first need to upload them to an image hosting site like Photobucket or Imageshack. Once you've got them uploaded, you need to to copy the IMG code for the image and past it into the body of your message.

curran · September 15, 2013, 08:07:07 PM

hey all!!! it looks like this thread is almost dead, BUT I have a question about this build. I have built one of these nice little pedals and modified it to taste(hoo ray for DIY) BUT the gain control seems to roll off a bunch of highs when it is turned down below 3pm on the pedal. I usually have it set up at 3:30 anyway BUT I would like to know if I can put a cap/resistor across the gain 1+2 lug like a guitar volume to retain the high end in the tone of the circuit. the circuit is 150k/.001 in parallel on the guitar vol. would this work or it there something different I could to to the circuit itself?

DixonVode · September 07, 2016, 01:26:42 AM

Hi

Is there any way I could use Voodoo Lab Pedal Power2 for powering the Liquid Foot 12?

bluegrasser12345 · November 30, 2016, 04:54:27 PM

In looking around for gut shots of this pedal, I came across this site with many good shots of the pcb:

http://e-motion.jp/voodoo-lab/post-606/

These shots show fewer parts than the schematic at the beginning of this thread, which could be attributed to less power filtering and no pulldown resistor. More curious however, is that there is clearly a 1k resistor near the top left corner of the board (above the yellow box cap). Could it be that this 1k resistor is R2 (shown as 10k) on the schematic above? Is it possible that R5 has been ommited altogether in the production pedal?

Any insight on these differences would be much appreciated. Thanks all!

c.stoffel · February 23, 2017, 10:18:03 AM

Hi, this is my version of the schematic for the Voodoo Lab Overdrive. It was based on the available schematics (by Justin Philpott and gaussmarkov), gut shots (some of the best ones are on the link posted by bluegrasser12345) and some info on the Voodoo Lab forum about capacitor values.

What do you guys think of it? Does it makes sense?

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Voodoo Lab Overdrive