SOLVED Electrovibe Deadish - Part Deux

[zachlovescoffee]

Howdy folks,

As I've moved on to other testing and troubleshooting for the nifty Electrovibe I'm running into some new problems. Namely, the "intensity" of the vibrato and chorus are basically not present. I have followed the DK Pedals tweaking method (here) and the Madbean Pedal Harbinger (here, pg 7). Alas, all to no avail. Also, the output in vibrato mode is VERY quiet, even with the volume at max.

I have output in all modes, bypass and when the pedal is engaged. Just barely to no effect and some other oddities.

The vibrato effect is there but not much intensity even when maxed and the chorus is basically non-existent. I've undertaken some additional troubleshooting and measured all of the pots. The speed and volume pots, while not 100% to their stated values all measured within 10kOhms of the stated values. The C100k dual gang pots on the other hand were unusual.

As soldered onto the board, measuring the wiper (middle) lug to ground, I only showed ~ 4k6 Kohms on the adjustment. Taking it to min-max only took it to 4K8. This was true for both intensity pots. So, I figured maybe bad pots? I pulled them out of the board and measured them. One measured at 99k and the other at 89k.

I don't have a schematic for this so I have no idea how to identify if those values on the board are normal or not. Any thoughts on where to go next?

 

[Robert]

You can find the schematic here:

https://docs.pedalpcb.com/project/ElectroVibe-Schematic.pdf

Vibrato mode is basically the wet signal without dry signal mixed in. Focus on why the vibrato signal is low, this is most likely the cause for chorus mode not working properly as well.

 

[zachlovescoffee]

You can find the schematic here:

https://docs.pedalpcb.com/project/ElectroVibe-Schematic.pdf

Vibrato mode is basically the wet signal without dry signal mixed in. Focus on why the vibrato signal is low, this is most likely the cause for chorus mode not working properly as well.

Will do. Does it make sense that the C100k pots are reading so low in the circuit? ~4k on the dial with almost no wiggle room seems unusual to me. Shorting maybe?

 

[Big Monk]

Howdy folks,

As I've moved on to other testing and troubleshooting for the nifty Electrovibe I'm running into some new problems. Namely, the "intensity" of the vibrato and chorus are basically not present. I have followed the DK Pedals tweaking method (here) and the Madbean Pedal Harbinger (here, pg 7). Alas, all to no avail. Also, the output in vibrato mode is VERY quiet, even with the volume at max.

I have output in all modes, bypass and when the pedal is engaged. Just barely to no effect and some other oddities.

The vibrato effect is there but not much intensity even when maxed and the chorus is basically non-existent. I've undertaken some additional troubleshooting and measured all of the pots. The speed and volume pots, while not 100% to their stated values all measured within 10kOhms of the stated values. The C100k dual gang pots on the other hand were unusual.

As soldered onto the board, measuring the wiper (middle) lug to ground, I only showed ~ 4k6 Kohms on the adjustment. Taking it to min-max only took it to 4K8. This was true for both intensity pots. So, I figured maybe bad pots? I pulled them out of the board and measured them. One measured at 99k and the other at 89k.

I don't have a schematic for this so I have no idea how to identify if those values on the board are normal or not. Any thoughts on where to go next?

Were you using a light shield?

 

[zachlovescoffee]

Were you using a light shield?

Yes sir! I cover that whole piece of the board in black electrical tape.

 

[Big Monk]

You should clean all the flux off while you have the circuit in the state it's in.

Did adjusting the gain/offset do nothing for the chorus side? Are you getting the proper voltages to the 15v portions of the circuit?

 

[Robert]

Does it make sense that the C100k pots are reading so low in the circuit?

If the speed of the lamp pulsing has a fair amount of range when turning the speed pot I wouldn't be too concerned with the in-circuit readings of the Rate pot at this point.

 

[zachlovescoffee]

Okay okay! I think I have it figured out, though I do want to get a better C100k pot installed that is more closely matched to the other. Matched speeds would be groovy.

I cleaned the heck out of it, removed the C100k's and re-flowed all of the heretofore un-touched blobs. I laid down a double layer of thick black electrical tape ~1mm under each. Then I re-made the lights shield and followed the MadBean Harbinger method again. Now I think I finally have an operational vibrato and chorus. I was getting sounds pretty. close to the DK Pedals demo. I'm fully clean into the amp with no drive or any other color.

Question -- does the light shield need to stay on once the pedal is buttoned up? I've seen various threads around here that indicated that it wasn't worth it/didn't have any impact one way or another.

The output volume appears to be low still. Are there any recommended mods to bring that volume up when it's maxed? It does not appear to be in unity with the bypass volume.

 

[JamieJ]

Have a look at @Big Monk elrctrovibe mods thread. I think it’s R4 (47k) from memory that needs to be bumped up to give it more volume.

I didn’t fit a light shield on mine and it sounds great. Good that you got it functioning.

 

[zachlovescoffee]

Have a look at @Big Monk elrctrovibe mods thread. I think it’s R4 (47k) from memory that needs to be bumped up to give it more volume.

I didn’t fit a light shield on mine and it sounds great. Good that you got it functioning.

I think it's this post: https://forum.pedalpcb.com/threads/electrovibe-big-monk.8576/page-2 and the value is 47k to 100k

 

[JamieJ]

I think others have used 1M or higher as well. I’ve been planning to mess around with mine but I haven’t got round to it yet.

 

[Big Monk]

I started with 100k, then bumped up to 470k, then finally settled on 2.2M.

 

[zachlovescoffee]

I started with 100k, then bumped up to 470k, then finally settled on 2.2M.

I'll socket the resistor (R4) and play around with some values. But I will start off with your 2M2 and see if that nails it for me! Did you find getting a matched pair of speed pots balanced out the speed or provided any benefit to unmatched?

 

[Big Monk]

Did you find getting a matched pair of speed pots balanced out the speed or provided any benefit to unmatched?

Nope. My issue was a lifted pad that opened the jumper trace on Speed 1. Once I identified that, I added a hard-wired jumper to replace the trace and it was fine.

You'd be fooling yourself if you think you can hear the difference that 9k ohms or so is providing for speed. You'll never have them at the same speed anyway.

I ended up bumping the speed resistors up as well to give both sides more maximum speed but I would make sure everything is kosher with yours before entertaining anymore mods.

 

[zachlovescoffee]

Nope. My issue was a lifted pad that opened the jumper trace on Speed 1. Once I identified that, I added a hard-wired jumper to replace the trace and it was fine.

You'd be fooling yourself if you think you can hear the difference that 9k ohms or so is providing for speed. You'll never have them at the same speed anyway.

I ended up bumping the speed resistors up as well to give both sides more maximum speed but I would make sure everything is kosher with yours before entertaining anymore mods.

Very helpful, as always! Thank you. The pedal is sounding pretty dang good right now! I have it sitting in an ESD bag now waiting for the enclosure to show up. I am going to keep it simple and do the faceplate plus the grey matte enclosure like you did. Simple and chill -- the vibes are in the box!

I'm pausing on any new builds now to shift focus to designing the box art for my hydra. I'm thinking of doing something similar to what @cooder did as it was such a classy and clean design.

I also have a Madbeans Total Recall that needs some love and attention from my newly built audio probe and newly acquired Rigol 1052E scope. I have no idea how to really use them so that'll be a few hours of research to figure it out The pedal is nearly functional just getting some nasty hum across bypass or wet signal and I haven't tuned it at all yet.

New builds must wait!

 

[zachlovescoffee]

Nope. My issue was a lifted pad that opened the jumper trace on Speed 1. Once I identified that, I added a hard-wired jumper to replace the trace and it was fine.

You'd be fooling yourself if you think you can hear the difference that 9k ohms or so is providing for speed. You'll never have them at the same speed anyway.

I ended up bumping the speed resistors up as well to give both sides more maximum speed but I would make sure everything is kosher with yours before entertaining anymore mods.

I have everything working well but I’m wondering which ones are the speed resistors? I want to try some more speed!

 

[Big Monk]

I have everything working well but I’m wondering which ones are the speed resistors? I want to try some more speed!

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...

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