Little VOODOO VIBE project by Kaputepalla

Vendt · Post by **Vendt** » 23 Sep 2012, 07:31

Thanx ik6gpy,

This is great!

kaeisy · Post by **kaeisy** » 25 Sep 2012, 20:04

And here´s what I had saved on my harddisk more than two years ago. Just the original Kaputepulla zip-file wihout mods.

Vendt · Post by **Vendt** » 26 Sep 2012, 06:01

Great Kaeisy!

This is a great project...Nice to have (practically) all files together. Would be nice to see some gut-shots of the project as well. As this is my first project involving LDR-LED ineteraction, I'm wondering how everyone got them connected without outside interference. Did you build a light box (small aluminium casing aroound LDR-LED or connect them with shrinksocket or nothing at all..

kaeisy · Post by **kaeisy** » 28 Sep 2012, 20:21

Hello Vendt,
I have to confess that I haven´t built this nice box yet. But if you take a look at the layout, you see that a lightbox probably won´t work, because the LDRs don´t surround one bulb light as in most univibe clones. I think you have to go for the heatshrink thing.

Cheers
kaeisy

RRIOS77 · Post by **RRIOS77** » 16 Apr 2013, 18:30

Hi, I saw the little voodo vibe in the first page, please could you update?, thanks so much man

nmbb · Post by **nmbb** » 31 Aug 2013, 19:33

Just saw this today, shame on me! I like the capacitor mod, but didn't get were to connect them... is it possible to post an uptade diagram with that mods?

nmbb · Post by **nmbb** » 31 Aug 2013, 20:59

ik6gpy wrote:Here's what i've got. There's everything to build a fully functional pedal. I included the cap switcher mod (switches between RT-18, Univibe e Voodoo Vibe caps).
Enjoy
Matteo

Another ham operator?

73

brejna · Post by **brejna** » 09 Jul 2015, 21:51

Hi everyone, could someone please post voltages of ICL8038 chip?
Thanks

yiyorebel · Post by **yiyorebel** » 20 Jul 2015, 21:52

Hello, someone has the off board wiring

, they were greatly appreciate .
best regards

idy · Post by **idy** » 21 Aug 2015, 21:02

Resurrecting an old thread: I want to try the voodoo-vibe lfo. I am looking at the same 2 page schematic with corrections that is posted above in the thread.

My question is about the "Bias" pot attached to the LEDs, or more accurately attached between one of the four LEDs and its 150ohm CLR.

Is it some kind of feedback? A voltage being taken off one of the LEDs, then buffered and mixed (with the lfo signal) into an opamp set up as a subtractor?

Knuddi · Post by **Knuddi** » 15 Jan 2016, 09:43

Does anyone have a complete "package" with updated schematics, layout and bill of materials?

Blitz Krieg · Post by **Blitz Krieg** » 18 Jan 2016, 09:08

viewtopic.php?f=13&p=31158#p31158

schem

krosa · Post by **krosa** » 25 Feb 2016, 23:36

wheres the layout?????

Yazoo55 · Post by **Yazoo55** » 07 Mar 2016, 16:42

I've got myself all worked up ready to go on this one. Are all the pots apart from the volume pot linear types please? Also, I couldn't see which way round they should be connected. Any advice would be appreciated.

I couldn't find a suitable rotary pot for the speed control, the one which switches between triangle and sine wave and switches between capacitor values so I've decided to use an spdt switch to select sine or triangle and connect this through to a standard rotary switch.

brejna · Post by **brejna** » 08 Mar 2016, 19:54

Just in case someone is interested in pcbs, I have some spares.. https://www.freestompboxes.org/viewtopic ... 16&t=27481

Cheers
Brane

Yazoo55 · Post by **Yazoo55** » 23 Mar 2016, 00:19

I've got mine finished. I had to debug it because I missed a small bridge on my etched board. I always have to resist the temptation to start removing components when this happens..."what if I just remove this and see what happens syndrome". There was a short to ground which stopped power getting to the transistors but I traced it through and eventually found a tiny bridge.

Has anybody used an expression pedal with this? If you have, any advice on setting up the two trimpots would be very welcome.

HellRaiser100 · Post by **HellRaiser100** » 24 May 2017, 09:31

Hi

Can someone explain me how i wire the speed range and chorus,vibrato,tremolo potis ?
And what potis should i use.

thanks

bajaman · Post by **bajaman** » 08 Oct 2017, 04:24

Hi folks
I have been playing around with many different phaser circuits recently and thought i would revisit my voodoo vibe build and apply some basic modifications. Using the schematic that has been floating around for many years (included below for your information), I decided to run some simulations to determine the optimum biasing characteristics for maximum undistorted signal headroom. The original Unicord /Shin ei/ Honey Univibe which the Voodoo Vibe was originally based on was designed to operate from approximately 18v dc whereas the VV runs off 9v dc power. Looking at the biasing for the Voodoo Vibe in the simulations shows that it is far less than ideal and so i set to work optimising this. Apart from being less than ideal, each of the phase shift stages has different value biasing resistors that frankly makes little sense - some have 180k/150k and others 180k/100k

The four stages should have identical biasing resistor values. only the fifth darlington emitter follower should have different values because it is not being used as a phase splitter like the first four stages. The gain recovery stage is very curious - no matter how i tried to optimise this stage it always distorted the signal on simulation. I can only suspect that roger mayer designed this stage to deliberately distort the signal in a very non linear manner for his own reasons but nowadays there are so many overdrive distortion pedals available that I feel it is unnecessary to have a recovery stage that introduces non linear amplification so i replaced this stage with an asp (anti symmetric pair) style circuit with 10dB of voltage gain - this is more than enough to balance the bypassed signal level, and of course can be adjusted by the proceeding output level control. Even a 1v peak to peak signal will not drive this stage into non linear mode now whereas with Mayer's design even 100mV will introduce significant 2nd harmonic distortion.

the final output emitter follower only needed a small change to it's biasing. I also increased the first phase shift capacitor to .022uf (was .015uf) to maintain the same response with the changed 150k bias resistor - now 100k.
After performing the mods I tried the pedal and feel it has a far clearer smoother sound than it had with the original component values. All the stages now have maximum voltage gain headroom for running from an 8v dc supply rail.
cheers

bajaman

: voodoo vibe 1.bmp (551.37 KiB) Viewed 3036 times

lhy0312 · Post by **lhy0312** » 08 Oct 2017, 18:06

As always, brilliant work! Bajaman

I'v been searching for VV data to build just these 2~3days, reading this thread frequently.. and your new post poped up. lucky for me.

I had similar suspicion about wierd constructions of audio buffers too. the unity gain issue on tremolo function would be solved I guess?
and I totally agree about that distortion in vibe circuit(even intended) is a redundancy..

Before build, I'm just gathering data and looking over previous build reports now. After all, build document of Brenja's Pangea is the final reference, but some questions remain..

In the build doc of Pangea, 1 of 4 cds is different one. 3*GL5549 + 1*GL5516.
(5549: 100-200k~10M / 5516: 5-10k~0.5M)

I couldn't find any reason of this. if the different one was for tremolo section, I might guess that makes sence.. but that cds is the last one of 3 phase stage(V4). I can't understand why.

And LED selection is the problem.. someone said this is most important thing in overall tone quality.

'diffused' type is certain thing, but the problem is other characters of led..

usually a low-bright, dull colored plastic case -'normal' led is used in this type ldr circuit, because its brightness reaction is linear.. I heard. In a modulation circuit(madbean multiplex Jr. ), gl5549+low bright yellow normal led combo worked great, as replacement of VTL5C3.

however someone report 'tinted' - clear and colored case, hi bright type showed good result.

I saw Bajaman used hi bright clear type led, even 3mm.

according to alessandro, leds in the original VV is 5mm and two types; dull colored(normal low)and clear colored(tinted hi).
I guess the former is 3 phase ldr, and the latter is tremolo ldr..??

bajaman · Post by **bajaman** » 08 Oct 2017, 19:35

On my original build back in 2007, I found it very useful to add a fifth led and current limiting 150 ohm resistor as an indicator on the front panel. This makes it very easy to set the intensity and sweep range (bias) controls for a smooth phase shift. In use, I found that i like to set the intensity control pot to around 10 o clock and the bias control pot to around 8 o clock to achieve the best sounding sweep.

I used identical led and ldr for all sections. Having the two outboard controls (bias and intensity) allows the use of a wide range of led types and allows you to zone in on the sweet spot very easily. I always leave the symmetry control on 12 o clock and the output level usually around 4 o clock. If I was to build another voodoo vibe, i would seriously consider using preset trim pots for these four controls.

cheers
bajaman

Little VOODOO VIBE project by Kaputepalla [documentation]