SOLVED My white whale… the electrovibe

Locrian99

Locrian99

Well-known member
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.

IMG_7180.jpeg

IMG_7178.jpeg IMG_7177.jpeg IMG_7174.jpeg IMG_7173.jpeg IMG_7172.jpeg IMG_7171.jpeg

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!
 
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Locrian99 said:
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.

View attachment 67315

View attachment 67317View attachment 67318View attachment 67319View attachment 67320View attachment 67321View attachment 67322

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!
Click to expand...
Not sure how and what you did, but one obvious- is the bulb going completely dark, and then lighting up?
Have you tested the resistance swing of the LDRs, just because you got them from a reliable source, doesn’t mean their supplier didn’t mess up etc.
and of course the pedal builders version of the default IT response (did you reboot) am- did you verify all component values and reflow joints?

Again if this is too “captain obvious” territory that you’ve explored before, I apologize as I don’t recall your previous thread (memory not what it was when I was young).

In any case, I feel your pain! We all have that one build, and sometimes it’s not even one as complex as this one that baffles us to no end - after 40+ years of building pedals, I finally got mine.. so we all get them!! Im sure with some of the minds here you’ll get this!
 
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Giorfida said:
Not sure how and what you did, but one obvious- is the bulb going completely dark, and then lighting up?
Have you tested the resistance swing of the LDRs, just because you got them from a reliable source, doesn’t mean their supplier didn’t mess up etc.
and of course the pedal builders version of the default IT response (did you reboot) am- did you verify all component values and reflow joints?

Again if this is too “captain obvious” territory that you’ve explored before, I apologize as I don’t recall your previous thread (memory not what it was when I was young).

In any case, I feel your pain! We all have that one build, and sometimes it’s not even one as complex as this one that baffles us to no end - after 40+ years of building pedals, I finally got mine.. so we all get them!! Im sure with some of the minds here you’ll get this!
Click to expand...
Captains obvious questions are often the answer.

Yes to the bulb, it goes completely off etc.

I haven’t measured the ldrs I’ll try that after work today.

I have reflowed. I do think I need to rewire much of the offboard wiring at this point. It’s solid core which I typically use but this has been moved around a lot more and I noticed some short like behavior. So I’ll be doing that tonight as well.
 
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Erik S said:
Yup. My bad. I couldn't see the first stripe.
Click to expand...
The love/hate relationship with MF resistors. With the 5th band I never know which side is up, while with the 4 band CF, and CC, you can’t mistake the gold or silver as the tolerance band

But other than that and the price, they really do outperform carbon types in every way
 
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Giorfida said:
The love/hate relationship with MF resistors. With the 5th band I never know which side is up, while with the 4 band CF, and CC, you can’t mistake the gold or silver as the tolerance band

But other than that and the price, they really do outperform carbon types in every way
Click to expand...
Why can’t they just use white or a lighter color so the color bands are even relevant?
 
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I would suspect the LDRs. I’ve never quite figured out how to spec and source those. I jus bought a whole bunch with different values and Mrs’s around until it works.

Not very scientific.
 
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jhaneyzz said:
I would suspect the LDRs. I’ve never quite figured out how to spec and source those. I jus bought a whole bunch with different values and Mrs’s around until it works.

Not very scientific.
Click to expand...
I’ll measure them tonight. They should be right as long as they are to spec as they are the ones mentioned in the build notes.
 
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Going to rewire the offboard stuff and take voltage measurements for thr 5088’s I’ll update after. It did seem like last night after the reflow I was getting more vibe sound but there’s a short someone in my offboard wiring so I need to find that.
 
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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.

Ok so here we go.

IC1 (the regulator)

I-16.92
G-0
O- 11.92

These are in order of left to right on the board was just easier for me that way. Whole lot of transistor measurements that I think all seemed good to me.

These are done by Transistor #/ E/ B/ C
15/.59/1.0/1.63
5/1.07/1.64/4.18
6/3.6/4.2/9.6
9/3.4/3.8/11.92
8/2.78/3.38/9.1
11/3.4/3.8/11.9
10/2.8/3.5/9.13
13/3.39/3.78/11.81
12/2.77/3.39/9.17
14/4.2/4.7/11.92
The following E/B are bouncing
1/4.5-8/4.9-6.9/16.92
2/4-7.6/3.9-8.4/16.93
3/4.5-6/5-6.7/14.7-15.5
4/5.3-6.7/5.6-7.2/14.6-15.4
 
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