ElectroVibe Modifications Thread

[Big Monk]

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 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.

2.) To increase depth at slow speed and increase overall speed available, Change C8 to 2.2u and R14/R15 to 1.5k.

If you want to modify further, see the link above to the Monk Vibe thread.

Please disregard the diagrams below. They are left for posterity.

I thought it might be a good idea to document some ElectroVibe mods while they are fresh in my mind:

 

[benny_profane]

An easier way might be to sub a smaller value in for R14/15.

This is the way to go to increase the speed. Try 3k3 or 2k7 and see if that gets you where you want to be. Note that you can lock up the lamp if you try to get it too fast.

 

[Big Monk]

This is the way to go to increase the speed. Try 3k3 or 2k7 and see if that gets you where you want to be. Note that you can lock up the lamp if you try to get it too fast.

The caps will work too (1/(R*C), etc.) but I think I agree 100% with you, i.e. the resistors are a better choice from a physical standpoint.

2.7k was actually the value I was thinking of.

@PedalPCB Can you confirm which resistors are in fact R14 and R15?

 

[Feral Feline]

Re pad-spacing: Put the speed-mod components on a switch; there's enough room up top to squeeze in another toggle.


Great thread idea, mod consolidation.

 

[NickC]

Unity vol mod

 

[Big Monk]

Can anyone give me a second set of eyes and see if I identified R14 and R15 properly?

 

[Big Monk]

Can anyone give me a second set of eyes and see if I identified R14 and R15 properly?

Bump for this. I have the circuit out of the enclosure bumping up R4. I’m trying to find them by continuity but not having luck.

 

[Big Monk]

So I confirmed the resistors labeled in my OP as R14/15 are correct.

Just finished up.

Replaced R4 with 470k and R14/15 with 2.7k.

 

[andare]

So I confirmed the resistors labeled in my OP as R14/15 are correct.

Just finished up.

Replaced R4 with 470k and R14/15 with 2.7k.

Haha so if 100k gave you unity then 470k gives you a boost, right?

I trust your values but I'll definitely socket those resistors when I build my Electrovibe, you never know, with different rigs pedals might behave differently. Also I have way too many sockets, need to use them eventually

 

[Big Monk]

Haha so if 100k gave you unity then 470k gives you a boost, right?

I trust your values but I'll definitely socket those resistors when I build my Electrovibe, you never know, with different rigs pedals might behave differently. Also I have way too many sockets, need to use them eventually

Well, 100k was just about unity, but I had to max out the volume. In reality, the value of R4 only gives incremental changes to the signal level past 250k, so I should probably be getting around 94% signal passing through versus the stock divider with 47k letting around 68% signal through.

 

[Big Monk]

So I took the last night's modifications for a brief spin and here are my thoughts:

1.) 470k for R4 actually brought it closer to true unity to my ears. It's very difficult to get a good measure of the bypassed vs. affected signal with modulation. I think if were to make a recommendation at this point it would be to just put the R.G. Keen recommended 2.2M in there and call it a day. I will likely do that myself tonight as a final modification.

2.) 2.7k for R14/R15 gives a very nice boost in maximum speed. It is not going to sound like a tremolo at full speed and it still is not even close to the full speed available on my Good Vibes, but it is a good deal faster than maximum at stock and there are no issues with the lamp at that value.

Once I get R4 swapped out for the last time, I'll start really digging in on comparing the units I have. At this point I am keeping both.

 

[pi.cast]

This is very interesting!
I'm also building my electrovibe and already the unity volume mod suggested by R.G. Keen. I'll try with a 2.2M resistor first as suggested, but I'll be able to swap it out since it has been socketed.

What is the bi-color led mod for? Is it supposed to flash at the same rate of the lamp?

Thanks!

 

[Big Monk]

What is the bi-color led mod for? Is it supposed to flash at the same rate of the lamp?

Thanks!

It provides a different color LED for each Speed. In my case, the Red half is the stock LED for Speed 1. For Speed 2, I used the Blue half for Speed 2 and also used a blue knob for Speed 2.

 

[Big Monk]

Can we talk biasing a bit? I now have 2 Univibe pedals in my arsenal, both with internal biasing arrangements.

How are you guys setting yours? What do you listen for? What is it you are after when biased "properly"?

 

[pi.cast]

Can we talk biasing a bit? I now have 2 Univibe pedals in my arsenal, both with internal biasing arrangements.

How are you guys setting yours? What do you listen for? What is it you are after when biased "properly"?

I was actually wondering the same as I'm finishing up the build.
Everybody just refers to generally adjusting the trimmer until the pedal sounds good. The point is, I have no idea of what "good" is supposed to mean in the case of a vibe pedal.

I guess I'll just proceed by trial and error.

 

[caiofilipini]

I used my Jam RetroVibe as a starting point. Set the speed and depth to about the same on both and adjusted both bias and gain until it sounded as close as possible to the RetroVibe. They'll never sound the same because the LFO is different on both, but I was able to get in the same ballpark.

From there, I tweaked it a little more until I was happy with what I was hearing.

 

[Big Monk]

I have built a couple vibes now and I use Brian's method:
Lamp Calibration
The GAIN and OFFSET controls are interactive. Use this procedure to calibrate the lamp • Turn Intensity and Volume controls all the way up. Set the Speed control at about half-way. • Turn the GAIN control up until you get moderate, but not overly bright lighting of the lamp. • Now adjust the OFFSET control to find the sweet spot for the vibe where you get the most lush and swirly sounds. The OFFSET will set the lower floor for the lamp brightness. High amounts of offset result in a lamp that goes fully off at the bottom of its sweep. Moderate and light offset means the lamp will pulse but never go fully dark. You will probably find yourself adjusting the GAIN and OFFSET a few times until you get the precise sound you want. I set my lamps to go fully dark to moderate brightness and get great results with that. Be careful when adjusting the trimmers so that the lamp does not blow. I have yet to do this in any build no matter where I set the trimmers, but it is possible to do. Lastly, you should consider turning off your power supply or disconnecting the DC jack when not in use. This will preserve the life of the lamp considerably

Yeah. I've been following that as well but I'm just having a bit of trouble getting it how I want it. I'm trying to get "swirly and lush" rather than "wompy and choppy".

I'll get there. I need to tweak a bit more.

 

[Bricksnbeatles]

Anyone think of implementing an expression option yet? I’m thinking I could get away with a pair of switched jacks connected to the two gangs of the rate 2 pot, and using a 100k dual expression pedal such as the Boss EV-3 with both jacks in use. I thought about using either a TRRS jack or a DIN jack and then creating my own dual gang expression pedal, but I don’t believe a switched DIN jack exists, and I can’t find a switched TRRS jack that has an isolated sleeve connection. Of course depth is an issue, but I think I have it worked out in a way where that won’t be an issue.

 

[Big Monk]

Anyone think of implementing an expression option yet? I’m thinking I could get away with a pair of switched jacks connected to the two gangs of the rate 2 pot, and using a 100k dual expression pedal such as the Boss EV-3 with both jacks in use. I thought about using either a TRRS jack or a DIN jack and then creating my own dual gang expression pedal, but I don’t believe a switched DIN jack exists, and I can’t find a switched TRRS jack that has an isolated sleeve connection. Of course depth is an issue, but I think I have it worked out in a way where that won’t be an issue.

One of the draws of the Good Vibes is the assignable expression output.

 

[Big Monk]

Make a light shield, hook up a looper and start turning trimmers till you get it. Easiest way to do it

I’ll make one tonight.