Electrovibe: No Signal

[nate_noise]

Hi Folks, I just boxed up the Electrovibe and am not getting any effect signal from it.
Bypass signal goes through fine, the lamp lights up and the gain/bias trimmers are working. I can hear a faint throbbing noise when the effect is engaged. I can effect the throbbing noise when I adjust the intensity and speed pots (speed footswitch seems to work too in that sense).

When I pulled it out of the enclosure to get the second photo, the wires to the chorus/vibrato switch came loose. (Would a weak connection on those result in no signal passing through?)

The very first time I plugged it in the lamp wasn't lighting up so I resoldered some of the weaker looking connections and the lamp started to work. My only concern now is that there might be a weak connection hiding underneath one of those double gang pots!

Any suggestions are welcome. Thanks!!

 

[Cybercow]

Socketed trannys can also be problematic. I prefer to gently "wrinkle" the ends of the legs on them to ensure a snug fit.

 

[nate_noise]

Socketed trannys can also be problematic. I prefer to gently "wrinkle" the ends of the legs on them to ensure a snug fit.

View attachment 69567

Thanks! I tried doing that (which is why some of them look so bent out of shape in the photos). How do you get yours nicely wrinkled? Just using your fingers or a tool?

 

[Coda]

Quadruple check that the short legs of the dual-gang pots aren’t shorting out on the joints beneath them…

 

[Giorfida]

Hi Folks, I just boxed up the Electrovibe and am not getting any effect signal from it.
Bypass signal goes through fine, the lamp lights up and the gain/bias trimmers are working. I can hear a faint throbbing noise when the effect is engaged. I can effect the throbbing noise when I adjust the intensity and speed pots (speed footswitch seems to work too in that sense).

When I pulled it out of the enclosure to get the second photo, the wires to the chorus/vibrato switch came loose. (Would a weak connection on those result in no signal passing through?)

The very first time I plugged it in the lamp wasn't lighting up so I resoldered some of the weaker looking connections and the lamp started to work. My only concern now is that there might be a weak connection hiding underneath one of those double gang pots!

Any suggestions are welcome. Thanks!!

The wires connecting the speed switch to the main PCB solder joints look a bit suspicious from the pic. If you have a couple coils joints there, check all of your other joints as they could be other ones as well

 

[Cybercow]

Thanks! I tried doing that (which is why some of them look so bent out of shape in the photos). How do you get yours nicely wrinkled? Just using your fingers or a tool?

I use a set of fine-tipped needle-nose pliers to wrinkle the leads.

 

[dcfvgb]

I would start by audio probing the base of Q6, see if the signal gets in that far. If it does, move up to base of Q9 and SW-1, if it doesn't, base of Q5 then Q15

 

[nate_noise]

Thanks everyone! It's working now but a little on the quiet side. In Chorus mode I only really get unity with the volume knob maxed out.
As per suggestions in the comment section of the store page, I used a 2M2 in R4 (instead of a 47K) which said that would provide unity at 2 o'clock. (I also socketed R12, R14 and R15 but am currently using resistors there as per specs on the build doc).
I also didn't mount the LDRs to be pointing right at the bulb, they're basically flush to the PCB, (not sure if that would have an effect on volume?).
The gain trimpot is turned up pretty much all the way.

Any thoughts on why it might be quiet?
Thanks!

 

[Coda]

Thanks everyone! It's working now but a little on the quiet side. In Chorus mode I only really get unity with the volume knob maxed out.
As per suggestions in the comment section of the store page, I used a 2M2 in R4 (instead of a 47K) which said that would provide unity at 2 o'clock. (I also socketed R12, R14 and R15 but am currently using resistors there as per specs on the build doc).
I also didn't mount the LDRs to be pointing right at the bulb, they're basically flush to the PCB, (not sure if that would have an effect on volume?).
The gain trimpot is turned up pretty much all the way.

Any thoughts on why it might be quiet?
Thanks!

Did you change R2 as well?…

 

[Robert]

Be careful with the Gain trimpot, that controls the bulb driver gain, not output level.

It's not common, but it's possible to burn out the lamp with excessive current.

 

[nate_noise]

Did you change R2 as well?…

I did not, it's 3K3. Should it be something different?

 

[Coda]

I did not, it's 3K3. Should it be something different?

Change R4 to 4.7M and Change R2 (stock preamp gain is 4) to increase gain. Here is a table of R2 values and corresponding gain increase:

3.9k = 4.25
4.7k = 4.91
5.6k = 5.66
6.2k = 6.16
6.8k = 6.66
7.5k = 7.25

Doing this fixes the unity gain issue and actually allows you to boost in the preamp, which can be quite useful.

ElectroVibe Modifications Thread

UPDATE 8/16/2023: I no longer recommend a lot of this stuff. In my opinion, there are better levers to pull and I have documented them here: The Monk Face: A Modernized Univibe With that said, let's discuss what I think are the most impactful and basic mods: 1.) Change R4 to 4.7M and Change...

forum.pedalpcb.com

Just finished building one too. I think I used 4k7 for R2, and it’s a bit above unity when maxed out…

 

[nate_noise]

ElectroVibe Modifications Thread

UPDATE 8/16/2023: I no longer recommend a lot of this stuff. In my opinion, there are better levers to pull and I have documented them here: The Monk Face: A Modernized Univibe With that said, let's discuss what I think are the most impactful and basic mods: 1.) Change R4 to 4.7M and Change...

forum.pedalpcb.com

Just finished building one too. I think I used 4k7 for R2, and it’s a bit above unity when maxed out…

Ah thank you! Perhaps I'll go up to 5.6K.

 

[nate_noise]

Volume seems to be improved after swapping to a 5.6K, wondering if I should also up R4 to a 4.7M.

The footswitches are both still noisy when stomped on, and the effect seems to stop working when I fully tighten all the nuts down onto the enclosure. I suspect an issue with the footswitch wires having poor connection. I've reflowed the solder on them and pushed the wires down into place a few times now. I think I made some fatal error in how I soldered it the first time around, I should have had everything screwed in place in the enclosure before soldering the footswitch PCB to the main PCB. Would have been nice if I soldered on the other side of the footswitch board, making the solder accessible while everythings screwed in place.

 

[Robert]

and the effect seems to stop working when I fully tighten all the nuts down onto the enclosure. I suspect an issue with the footswitch wires having poor connection.

Did you insulate the back of the two dual (Speed) potentiometers?

Electrical tape usually isn't good enough. The component leads puncture it and short against the pots, which happen to be ground when you tighten the hardware down in the enclosure.

 

[nate_noise]

Did you insulate the back of the two dual (Speed) potentiometers?

Electrical tape usually isn't good enough. The component leads puncture it and short against the pots, which happen to be ground when you tighten the hardware down in the enclosure.

Ah that could be it! I had two layers of electrical tape, but its possible there's a puncture.

I just put the plastic washer from the footswitch on the inside of the enclosure and that seemed to help things all be a little less tight and now functional. But I should probably get some proper pot covers for those dual gang pots.

I tried toggling the footswitches while fiddling with components inside and it seems like the socketed trannies were maybe a bit loose and causing that footswitch noise. Thinking I'll go through those all and make sure theyre super tight. Do people ever hot-glue over socketed components once they're happy with results? I'm just worried things might shake loose again over time, even with the 'crimped' ends.

 

[Coda]

Ah that could be it! I had two layers of electrical tape, but its possible there's a puncture.

I just put the plastic washer from the footswitch on the inside of the enclosure and that seemed to help things all be a little less tight and now functional. But I should probably get some proper pot covers for those dual gang pots.

I tried toggling the footswitches while fiddling with components inside and it seems like the socketed trannies were maybe a bit loose and causing that footswitch noise. Thinking I'll go through those all and make sure theyre super tight. Do people ever hot-glue over socketed components once they're happy with results? I'm just worried things might shake loose again over time, even with the 'crimped' ends.

You can tack some solder into one of the sockets…

 

[chris.knudson]

But I should probably get some proper pot covers for those dual gang pots.

The clear plastic from packaging works -- not the thin stuff, but the harder plastic like the packaging that batteries come in. You can use a piece of double sided tape to attach it to the back of the pot. I've also seen people use the plastic pull out disc from a milk carton or orange juice container.

 

[Giorfida]

The clear plastic from packaging works -- not the thin stuff, but the harder plastic like the packaging that batteries come in. You can use a piece of double sided tape to attach it to the back of the pot. I've also seen people use the plastic pull out disc from a milk carton or orange juice container.

I used some fishpaper for mine (didn't realize PpCB had insulators). Good stuff to keep on hand!

 

[nate_noise]

The clear plastic from packaging works -- not the thin stuff, but the harder plastic like the packaging that batteries come in. You can use a piece of double sided tape to attach it to the back of the pot. I've also seen people use the plastic pull out disc from a milk carton or orange juice container.

great idea. any way to keep this hobby more environmentally friendly! (I couldnt believe how much individual plastic packaging came with my last digikey order. I felt bad seeing it all go in the bin.)