SOLVED My white whale… the electrovibe

[Locrian99]

Alright so some point I think last spring I built an Electrovibe. I have never gotten it to work correctly. It is the only pedal I’ve ever literally just given up on. I revisit it everyone once in awhile but I’m yet to figure it out.

Issue: signal passes, I get a very mild effect. I have twisted trimmers for what feels like hours with a looper playing and I just don’t get anything beyond a subtle throb really. And that’s only really with the intensity maxed and speed maxed. I find if I do what is described in the biasing portion of dk pedals demo I get the greatest effect. Gain turned to max then backed off a little, bias set to min then slowly turn up a little.

I did do a couple of mods that I believe Chuck d bones recommended at some point in my struggles with this thing. Which were change a couple electro 1u to film and one to 2u2 I think. Didn’t make much of a difference. And did the gain mod.

Using 9203 ldr’s I purchased from digikey.

My light shield for this.





I’m hoping someone either can a tell me where to look that might be causing the effect to be subtle or maybe see some glaring mistake that I’ve been staring at and just my blinders won’t let me see.

At this point it’s a matter of pride I need to get this right .

Thanks!

 

[Locrian99]

So I have a good vibe for what I would expect to be moderate intensity and fastish speed (far from like a ring mod though) at max intensity and max speed. If I turn either control down you can tell the tone is being affected almost like a phaser that isnt sweeping. But you don't really hear the effect. I can only hear the effect maybe the last 3rd of the intensity knob. I may make a video tomorrow evening if I have time.

 

[KR Sound]

Here’s a pic of the one I built for reference if it helps any. Built it for a friend so I don’t have it in hand to get any values unfortunately, but hopefully you figure it out.

 

[Robert]

Alright so one thing that I now remember bugged me about this is the regulator clearly states it should be a 78l12. But the schematic references every point off the regulator should be +15v. I figure enough people have built this over the years with only the schematic referencing 15v that the 12 must be accurate.

12V is correct.

The project originally had a 15V regulator but because of voltage drop across the diodes the charge pump wasn't putting out high enough voltage for it to regulate properly.


If you do make a video show what the lamp is doing when it's pulsing it's strongest.

I have a mini (same circuit) here, I'll see if I can make some voltage measurements today.

 

[Locrian99]

12V is correct.

The project originally had a 15V regulator but because of voltage drop across the diodes the charge pump wasn't putting out high enough voltage for it to regulate properly.


If you do make a video show what the lamp is doing when it's pulsing it's strongest.

I have a mini (same circuit) here, I'll see if I can make some voltage measurements today.

we’ll see looks like my brick from stomp box parts and my soroing deluxe board should be here today this might get bumped in priority

 

[Big Monk]

Keep in mind that the Phase Section of the Vibe is HUGE and has a ton of components.

The first step to troubleshooting should be to check where the signal exits the preamp and where it reemerges at the mixer and volume control.

If you are certain you are passing a legit signal to the phase stages, check each phase stage in succession.

If you are certain you have no errors, bad joints or questionable points in the path of the phase stages, move to the LFO. Regardless of the the level of phasing, the LFO, if correct and functioning, should still be acting upon the bulb.

This is a tough project, and while designed and implemented very well by @Robert, it's not a beginner's project and I have seen a ton of these give people issues over the last few years because of the sheer amount of components and what looks like very rushed and questionable population of the boards.

I even messed up my first.

You have to take your time.

My opinion and advice? Scrap it and start again. If you are like me, You won't be satisfied knowing what a mess it is inside once you get it going anyway.

 

[Robert]

One thought, are you trying both modes?

Vibe mode is much more subtle than chorus mode, and as counterintuitive as it is, Chorus mode is the "Univibe" sound.

 

[Locrian99]

One thought, are you trying both modes?

Vibe mode is much more subtle than chorus mode, and as counterintuitive as it is, Chorus mode is the "Univibe" sound.

yea I’ve tried both one is far more subtle than the other as you say. Well where it is right now one seems almost non existent compared to the other.

 

[Giorfida]

yea I’ve tried both one is far more subtle than the other as you say. Well where it is right now one seems almost non existent compared to the other.

Not going back to quote the exact post. I’m lazy, but you stated the LDR are going up and down, but do you remember your resistance at full light vs full dark? As that’s the big difference between the different part numbers.
It sounds like you are sooooo close, yet so far away here!

 

[Locrian99]

My dmm doesn’t react fast enough to really measure while the light is flashing. They were all pretty consistent in their readings.

If had them sitting in just the light from the room (the pedal did not have power to it) there would be 10kish, if I shined a flash light on it it would get lower. Once I covered it with a light shield it would jump to 7-8M and steadily increase over time. I really don’t think the problem is with the ldrs

 

[Locrian99]

If you are certain you are passing a legit signal to the phase stages, check each phase stage in succession

for the longest time I was convinced this was a biasing issue because I get effect just not near what I hear from any if the demos and only when intensity and speed are basically maxxed. I actually bought a looper so o could sit there and turn trimmers with two free hands for this.

Would it be possible for one of the phase stages or multiple of them to have an issue but the effect still pass just with less stages of phase. I have to wonder if that is what may be going on here. But then I would think k would see it in my transistor voltages wouldn’t I?

I’ve built pedals as complicated as this one parts wise without issue. Duo phase etc. I’m sure it’s gotta just be a good joint or something somewhere (though I’ve reflowed everything other than what is under the speed pots). I suppose I could solder those from the top though just to double check.

It’ll take ages but I suppose I could just trace it out from the schematic and verify everything is connected to the next part.

 

[Locrian99]

I don’t exactly see why this is reading this way. R25/43/49 all read 32.5k ish. R55 is reading 28k ish. All are 47k resistors by color codes. Lifted one leg of r55 just to confirm and it is reading 47k. Obviously it’s interacting they are interacting with something here. Not sure what is going on there exactly.

 

[Locrian99]

Well I think got it. Best I can tell it was solved by reflowing one of the solder joints that was below the dual gang speed pots. I basically soldered them from the component side. I now have effect through out the turn of the intensity knob. And speed knob.

 

[Dan]

Why can’t they just use white or a lighter color so the color bands are even relevant?

Why can't they just print the value...

 

[Locrian99]

Why can't they just print the value...

There are some where they do, I believe they are rather expensive though.

 

[Giorfida]

Why can't they just print the value...

For those of us in our 50s, thankfully they still use the color code. I can still read color codes w/o magnification under most light… caps and parts with fine print? Not so much

 

[Coda]

I apologize for not suggestion the dual-gangs when I first started following this thread. I usually always suggest to triple check the dual gang when there is one present. 80% of the time it’s the dual-gang everytime…

 

[Locrian99]

I apologize for not suggestion the dual-gangs when I first started following this thread. I usually always suggest to triple check the dual gang when there is one present. 80% of the time it’s the dual-gang everytime…

Wasn’t the actual pot it was the solder joints under there you can’t get to I think is what did it. I was measuring some stuff too and lifted some legs to do it. Everything was in the phaser section though and all the parts are the same had to be a soldering issue I guess.