# ElectroVibe Modifications Thread



## Big Monk

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


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## benny_profane

Big Monk said:


> 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.


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## Big Monk

benny_profane said:


> 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?


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## 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.


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## NickC

Unity vol mod 👍


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## Big Monk

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


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## Big Monk

Big Monk said:


> 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.


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## 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.


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## andare

Big Monk said:


> 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


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## Big Monk

andare said:


> 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.


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## 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.


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## 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!


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## Big Monk

pi.cast said:


> 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.


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## 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"?


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## pi.cast

Big Monk said:


> 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.


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## 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.


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## Big Monk

thewintersoldier said:


> 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.


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## 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.


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## Big Monk

Bricksnbeatles said:


> 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.


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## Big Monk

thewintersoldier said:


> 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.


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## NickC

i put on the 2.2M resistor , sound perfect, there is no more level drop, finally I can "solder" the lid of this damn pedal and never open it again!!!  😆


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## Big Monk

Does anyone know what the Symmetry control on the Electronic Orange Moon Vibe and RM Voodoo Vibe does? 

I have a feeling it’s a topside LFO offset control. The Voodoo Vibe has a topside bias control as well.


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## Big Monk

Further investigation of the Electronic Orange manual and the Roger Mayer Voodoo Vibe seems to indicate that the Electronic Orange "Symmetry" control is in fact the Offset we know from the EV. The Bias or Gain control is a trim on the inside like the EV. Also, the Moon Vibe has an internal Volume trimpot, which seems silly as you can just make that resistor bigger in a fixed version.

The RM Voodoo Vibe has a bunch of stuff going on but nothing too crazy. "Symmetry" is again just the Offset control and Bias is external. I'm not sure what is happening with the Speed Range control but I assume it varies the resistors in the speed circuit to expand the range.

I'm entertaining a small breakout board for use with my EV Mini that will use these pots for external control of Offset and Gain:









						250K OHM Linear Taper Potentiometer Round Knurled Plastic Shaft PCB 9mm
					

ALPHA - Get It Fast - Same Day Shipping




					www.taydaelectronics.com


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## ntuncer

Here is what I found for the mini boards, correct me if I am wrong. it could be useful to add bi-color led without using them.

Vibe is normal true bypass wiring.
Speed is like below


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## ntuncer

When Speed footswitch off, Speed 2 knob controls, when on, Speed 1 knob. Is it possible to inverse it? If yes could you please explain?

Cheers


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## Big Monk

ntuncer said:


> When Speed footswitch off, Speed 2 knob controls, when on, Speed 1 knob. Is it possible to inverse it? If yes could you please explain?
> 
> Cheers



Since the switch goes between the 2 speeds, I wouldn’t think of it as an On/Off switch but rather an On/On.


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## ntuncer

Big Monk said:


> Since the switch goes between the 2 speeds, I wouldn’t think of it as an On/Off switch but rather an On/On.


Any idea how to reverse it? I didn't use the speed mini pcb, directly soldered the cables.


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## Big Monk

ntuncer said:


> Any idea how to reverse it? I didn't use the speed mini pcb, directly soldered the cables.



Do you mean the LED being on/off?


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## ntuncer

Big Monk said:


> Do you mean the LED being on/off?


yes when the speed led off means speed 1 knob active when the led on speed 2 knob active.


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## Big Monk

ntuncer said:


> yes when the speed led off means speed 1 knob active when the led on speed 2 knob active.



You could attack this 2 ways:

1.) Simply swap the wire that that comes into the foot switch from the LED to its opposite pole or;

2.) Use a Bi-color LED. I used Red/Blue and have a blue knob on speed 2:


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## ntuncer

Big Monk said:


> You could attack this 2 ways:
> 
> 1.) Simply swap the wire that that comes into the foot switch from the LED to its opposite pole or;
> 
> 2.) Use a Bi-color LED. I used Red/Blue and have a blue knob on speed 2:
> 
> View attachment 22567



For the first option, speed led has a continuity on the pin 5. Should I change the opposite pole like below?

Before:





after


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## Big Monk

ntuncer said:


> For the first option, speed led has a continuity on the pin 5. Should I change the opposite pole like below?
> 
> Before:
> 
> 
> 
> 
> after
> View attachment 22584



Yes.


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## Big Monk

Adjusted the OP to include and annotated schematic:


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## nkt$275

Has anybody posted what appears to be the choice hfe for the 2N5088 transistors ?
Big Monk you ROCK !
Will you post a photo of the inside of your Electrovibe with all the mods ?


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## Big Monk

nkt$275 said:


> Has anybody posted what appears to be the choice hfe for the 2N5088 transistors ?
> Big Monk you ROCK !
> Will you post a photo of the inside of your Electrovibe with all the mods ?



There’s really nothing to see on the inside. Rather, the mods are all on board components with different values or hidden underneath the board.


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## ADAOCE

nkt$275 said:


> Has anybody posted what appears to be the choice hfe for the 2N5088 transistors ?
> Big Monk you ROCK !
> Will you post a photo of the inside of your Electrovibe with all the mods ?


I wondered this at first too but was told by others that they didn’t check transistors. I just soldered in the first 14 2N5088s I could find and it sounds 🤌


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## Bricksnbeatles

Could you post a little clip of what the phase balance control sounds like?


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## Big Monk

Bricksnbeatles said:


> Could you post a little clip of what the phase balance control sounds like?



I don’t have that mod implemented yet. Was going to go in sometime this week and do it.


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## Bricksnbeatles

Big Monk said:


> I don’t have that mod implemented yet. Was going to go in sometime this week and do it.


Just looked at the schematic— It’s essentially the wet-dry balance in chorus mode though, right? Seems useful— I’d be tempted to put it on my EV build (when I eventually get around to it) if it wasn’t for the fact that it doesn’t fit the aesthetic I’ve laid out for my build


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## Big Monk

Bricksnbeatles said:


> Just looked at the schematic— It’s essentially the wet-dry balance in chorus mode though, right? Seems useful— I’d be tempted to put it on my EV build (when I eventually get around to it) if it wasn’t for the fact that it doesn’t fit the aesthetic I’ve laid out for my build



Yes. The depth of the 2 stages of phasing from the Univibe relies on the frequency cancellation provided by balancing the gains of the wet/dry signals. 

At least that’s what R.G. Keen says.


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## zgrav

For the trim pot to set the wet/dry signal levels for better phasing, I am going to omit R16 and R17 and put a 200K trim pot in the board, each outside leg on the non-common side with the middle pin going to the common side.


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## Big Monk

zgrav said:


> For the trim pot to set the wet/dry signal levels for better phasing, I am going to omit R16 and R17 and put a 200K trim pot in the board, each outside leg on the non-common side with the middle pin going to the common side.



The whole point of the fixed resistors and smaller trimpot is for better control of the balance.


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## zgrav

Big Monk said:


> The whole point of the fixed resistors and smaller trimpot is for better control of the balance.


Understood.  Are you suggesting there is not enough control for the 200K trim?  Not as fine detail as the 50K trimmer, but I suspect it will be fine for dialing in the balance.  Much cleaner install on the board.


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## Big Monk

zgrav said:


> Understood.  Are you suggesting there is not enough control for the 200K trim?  Not as fine detail as the 50K trimmer, but I suspect it will be fine for dialing in the balance.  Much cleaner install on the board.



Yes. If you were trying to hit the broadside of a barn I’d say use 200k and no fixed resistors but you are targeting complete cancellation which means the right balance.  A tight balance at that.

Definitely do what you want but I think the mod is better served with fixed resistors and a smaller trimmer.

Keep in mind that other combos would work as well: 91k resistors and 10k trimmer, 82k resistors and 20k trimmer, etc.

As an anecdote: I had a 500 ohm trimmer on the power rail of my Protoboard for fine adjustment of voltage and it was a nightmare. Couldn’t hit consistent target voltages for shit because of how large (relatively) it was compare to the normal < 100 ohm series limiters on power in.

Anecdote of an anecdote: There are at least 3 threads I found in my Vibe research from DIYSB and everyone who tried what you are going to was less than pleased with the control they had over the mix.


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## zgrav

Big Monk said:


> Yes. If you were trying to hit the broadside of a barn I’d say use 200k and no fixed resistors but you are targeting complete cancellation which means the right balance.  A tight balance at that.
> 
> Definitely do what you want but I think the mod is better served with fixed resistors and a smaller trimmer.
> 
> Keep in mind that other combos would work as well: 91k resistors and 10k trimmer, 82k resistors and 20k trimmer, etc.
> 
> As an anecdote: I had a 500 ohm trimmer on the power rail of my Protoboard for fine adjustment of voltage and it was a nightmare. Couldn’t hit consistent target voltages for shit because of how large (relatively) it was compare to the normal < 100 ohm series limiters on power in.
> 
> Anecdote of an anecdote: There are at least 3 threads I found in my Vibe research from DIYSB and everyone who tried what you are going to was less than pleased with the control they had over the mix.


Thanks.  I will see how it works out.  Easy to see that there is much more control with the other combo, and I may switch to that after I give it a go.  BTW  --- did you sub the 10U caps for the 1U in your build?  And do you think you can hear a difference with them?  

Thanks for all the work you put into researching, testing, and laying out the mods so clearly on the documents.  Those were big factors in deciding to go ahead an put together the electrovibe board.


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## Big Monk

zgrav said:


> Thanks.  I will see how it works out.  Easy to see that there is much more control with the other combo, and I may switch to that after I give it a go.  BTW  --- did you sub the 10U caps for the 1U in your build?  And do you think you can hear a difference with them?
> 
> Thanks for all the work you put into researching, testing, and laying out the mods so clearly on the documents.  Those were big factors in deciding to go ahead an put together the electrovibe board.



My ElectroVibe does not have the 10 uF caps. 

I’m working in a board design now so that I can experiment. 

Honestly, just use the fixed resistors and smaller trim. You are not doing yourself any favors with the 200k trim by itself.


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## zgrav

@Big Monk   -- looking at your diagrams, did you think about turning the bicolor LED into the blinking rate light as well?  Looks like you could power the bicolor LED from the C14 point and have serial resistors on each of the separately switched ground wires.  I may give that a try.


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## Big Monk

zgrav said:


> @Big Monk   -- looking at your diagrams, did you think about turning the bicolor LED into the blinking rate light as well?  Looks like you could power the bicolor LED from the C14 point and have serial resistors on each of the separately switched ground wires.  I may give that a try.



My rate LED is separate.

The design I’m working on now ditches the Bi-color altogether for separate diffused Speed indicators.


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## zgrav

Big Monk said:


> My rate LED is separate.
> 
> The design I’m working on now ditches the Bi-color altogether for separate diffused Speed indicators.


Sounds nice!


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## zgrav

Update on the trim pot for balancing wet and dry signals.   Using the 200K trimmer works OK for dialing in a better sound when you are adjusting the setting, and I did not get the feeling that it was hard to hit the sweet spot.  I am curious to see how much better it would be to get more detail in the trimmer, so I am going to mod a madbean Harbinger pedal I built a few years ago and try the 82K/50K trimmer combination.  

For the Electrovibe build I skipped putting in the bi-color or rate LEDs for now since I just wanted to try check out the sounds.  I subbed the 10K caps for the 1K (except for the last one in the chain, deferring to RGK).  Happy with the sound but can only compare it to the Harbinger, which I also like.


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## Big Monk

thewintersoldier said:


> View attachment 23723



To be fair, none of the mods are mine.


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## Big Monk

thewintersoldier said:


> I was gonna post this but I wasn't sure how @zgrav would take it, but it's too good not to post. Hope you got a sense of humor Z.
> View attachment 23725


We need to bring back the LOVE/LOL emoji


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## zgrav

thewintersoldier said:


> I was gonna post this but I wasn't sure how @zgrav would take it, but it's too good not to post. Hope you got a sense of humor Z.
> View attachment 23725


What to say, Hmmmmm..   ROTFLMAO


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## Big Monk

thewintersoldier said:


> @Big Monk Here is your new logo, embrace who you really are.
> View attachment 23730



I like that!


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## Big Monk

thewintersoldier said:


> Use it, I can send you the SVG. It should be on your pedals



I goofed around with it this morning and combined aspects of my current logo:




with the logo you sent me and came up with this:





I'm only disappointed you didn't send this before i ordered the first batch of One Knob Fuzz Face boards!


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## zgrav

It takes cork sniffery to a new level.  Not necessarily a _higher level_, but a new one!


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## Crispy

thank you everyone that helped with mods to this Electrovibe circuit , i was having low volume on my chorus and my sweep didnt have that nice wobble i was wanting, (it was a nice sweep just more like a even sounding phaser sweep) after changing out a bunch of the 1uf electrolytic for 10UF electrolytic ,changing R4 to 2m2 , the R16/17 mod with a pot my Univibe now has the wobble and volume i was hoping it would have . thank you to everyone involved with this build. i still have a stalling problem with my lfo, if i slow it down to much ,i noticed my lfo does not get very fast even at max ill have to try the speed mod next


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## nkt$275

Which 1uf electrolytic caps did you change to 
10uf? AND what does it do exactly?


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## Big Monk

nkt$275 said:


> Which 1uf electrolytic caps did you change to
> 10uf? AND what does it do exactly?



Read the first post of this thread.


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## nkt$275

Yes I figured that out …
Apologies -
Somehow I got to the last page first.


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## Big Monk

nkt$275 said:


> Yes I figured that out …
> Apologies -
> Somehow I got to the last page first.



No sweat! Just saved me the typing is all.


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## fig

Big Monk said:


> I goofed around with it this morning and combined aspects of my current logo:
> 
> View attachment 23736
> with the logo you sent me and came up with this:
> 
> View attachment 23737
> 
> I'm only disappointed you didn't send this before i ordered the first batch of One Knob Fuzz Face boards!


How did I miss this? Sock it to 'em Derek! Looks great!


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## zachlovescoffee

Hey Might-Monk! First off, hat tip to you and your contributions to builds and mods and of course, usually always being the first to respond to my threads. @fig too 

Did you special 250k and 500R pots for the external adjustments? Like smaller bodied pots or regular sized jammers with smaller knobs? Are they log, linear or audio pots? I'm loving my Electrovibe but I want to be able to dial in the lush/swirl and taking it apart is a PITA. Thanks mate!


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## fig

zachlovescoffee said:


> usually always being the first to respond to my threads. @fig too


Do I? Groovy! 🥰


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## Big Monk

zachlovescoffee said:


> Hey Might-Monk! First off, hat tip to you and your contributions to builds and mods and of course, usually always being the first to respond to my threads. @fig too
> 
> Did you special 250k and 500R pots for the external adjustments? Like smaller bodied pots or regular sized jammers with smaller knobs? Are they log, linear or audio pots? I'm loving my Electrovibe but I want to be able to dial in the lush/swirl and taking it apart is a PITA. Thanks mate!



I used 250kB and 1kB, respectively. There were Bog Standard 16 mm solder tab pots with small fluted knobs.

I actually sold mine last week. I have an ElectroVibe Mini coming and I am going to use the externally adjustable trim pots and a custom drilled enclosure.


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## joelorigo

For any one interested, here's the diagram at the beginning of this thread color coded by the mod. I'm looking at this project and the colors help my brain.


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## andare

joelorigo said:


> For any one interested, here's the diagram at the beginning of this thread color coded by the mod. I'm looking at this project and the colors help my brain.
> 
> View attachment 25071


Big thanks for this!


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## joelorigo

I'm looking at this and thinking about the mods I want to do and I just realized that in the color coded document I posted above, I missed one component - C20. I don't see it mentioned in any of the text boxes describing the mod. What am I missing?


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## Big Monk

joelorigo said:


> I'm looking at this and thinking about the mods I want to do and I just realized that in the color coded document I posted above, I missed one component - C20. I don't see it mentioned in any of the text boxes describing the mod. What am I missing?



Doesn't require changing.


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## joelorigo

I'm sorry to ask this when I know it's out there somewhere, but ugh! I've just searched and searched.

Is there a way to reverse how the left LED (the SPEED one) works, so that it lights up or SPEED 2?


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## Big Monk

joelorigo said:


> I'm sorry to ask this when I know it's out there somewhere, but ugh! I've just searched and searched.
> 
> Is there a way to reverse how the left LED (the SPEED one) works, o that it lights up or SPEED 2?



I don’t think so without modifying the breakout board.


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## joelorigo

I found it! It's on page 2, posts 27-34 of this thread. What exactly can be done? Changing the way a couple of the connections between the breakout board and the main board?


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## Big Monk

joelorigo said:


> I found it! It's on page 2, posts 27-34 of this thread. What exactly can be done? Changing the way a couple of the connections between the breakout board and the main board?



I still think you'd have to cut the trace on the breakout board to swap it. The top lug on the middle switch is tied to ground permanently with a trace so simply swapping the LED connection from the bottom lug to the top would result in the Speed LED always being on.


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## joelorigo

I see. Would not using the breakout board make this possible?


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## Big Monk

joelorigo said:


> I see. Would not using the breakout board make this possible?



Yup. If you just use a switch and run the LED to the top middle lug, the LED will come on for Speed 2 I believe.


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## joelorigo

Like this?


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## Big Monk

joelorigo said:


> Like this?
> View attachment 25292



No. Pad 4 on the board is ground I believe. It needs to go on the middle lug of the middle switch.


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## joelorigo

I see, thank you. Like this one then?


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## Big Monk

joelorigo said:


> I see, thank you. Like this one then?
> View attachment 25293



You got it! 

That should light up the Speed LED when Speed 2 is active. 

If you are foregoing the breakout board, you can use a bi-color LED and a different knob color for Speed 2 as well. I used a Blue/Red, common anode LED and a Blue knob on Speed 2 to differentiate on my original Big ElectroVibe.


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## joelorigo

Thank you. I saw that you did that. That’s cool. I have been studying all of your Electrovibe threads. I’m thinking about which of the mods I want to implement. I will definitely have more questions.

Thanks from all of us for all the work you have put in to this project!


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## Big Monk

joelorigo said:


> Thank you. I saw that you did that. That’s cool. I have been studying all of your Electrovibe threads. I’m thinking about which of the mods I want to implement. I will definitely have more questions.
> 
> Thanks from all of us for all the work you have put in to this project!



Thank @PedalPCB!


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## joelorigo

Yes! Thank you @PedalPCB!


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## Raspymcnasty

joelorigo said:


> For any one interested, here's the diagram at the beginning of this thread color coded by the mod. I'm looking at this project and the colors help my brain.
> 
> View attachment 25071


is C7 supposed to be 10u as well? @bigmonk

So far I have the following mods noted.
R4 - 2M2 - Unity vol mod
R12 - 5M - Slow speed mod
R14/R15 - 2k7 high speed mod
C7/C10/C13/C15/C21/C23/C24/C26 - 10 uF - Low end mod
Q3/Q4 - 2N3904 - Reliability mod
Q14 - MPSA13 - darlington final phase stage mod

does this all look correct? or any suggestions for testing?


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## Big Monk

Raspymcnasty said:


> is C7 supposed to be 10u as well? @bigmonk



No. C7 is in the Speed section.


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## Raspymcnasty

Big Monk said:


> No. C7 is in the Speed section.


I just wanted to double check since the explanation on the image on the first page explained you did it to C7 as well. Do my mod listings above look correct? Thank you btw.


----------



## Big Monk

Raspymcnasty said:


> I just wanted to double check since the explanation on the image on the first page explained you did it to C7 as well. Do my mod listings above look correct? Thank you btw.



That’s a direct quote from R.G. Keen, not me. 

The caps noted specifically on the drawing and refdes are the ones to change because they actually correspond to the Electrovibe.


----------



## Big Monk

@joelorigo

These are the actual caps to change with respect to the Electrovibe;


----------



## joelorigo

A couple more questions about mods. (Sorry I am hijacking this thread for my personal interests. Let me know if I should delete this post and start a new thread.)

I am interested in these mods: Unity Gain, Min/Max Speed, Low End & 2nd Phase, Phase Mix & Reliability & Darlington. There is no reason these can't all be implemented at the same time, right?

For the Min/Max Rate Mod, a resistor of 5M or above at R12 for extended range at slow speeds? Has anyone experimented with these values?

For the Phase Mix Mod, it is having one end of R16 & R17 connected to the board, connecting the other ends to a lug of 50k trim pot, then another leg of the trim pot back to the open R16 & R17 pads?


----------



## Harry Klippton

😚😚


----------



## Big Monk

joelorigo said:


> A couple more questions about mods. (Sorry I am hijacking this thread for my personal interests. Let me know if I should delete this post and start a new thread.)



There’s a lot to unpack here. I’ll do my best. 



joelorigo said:


> I am interested in these mods: Unity Gain, Min/Max Speed, Low End & 2nd Phase, Phase Mix & Reliability & Darlington. There is no reason these can't all be implemented at the same time, right?



Unity gain is a no brainer and only a single resistor swap. Min/Max speed is also a resistor only mod. The cap mods are simply component swaps. Single resistor to Darlington swaps are straightforward as well. 



joelorigo said:


> For the Min/Max Rate Mod, a resistor of 5M or above at R12 for extended range at slow speeds? Has anyone experimented with these values?



Not that I know of. That’s directly cribbed from J.C. Maillett.



joelorigo said:


> For the Phase Mix Mod, it is having one end of R16 & R17 connected to the board, connecting the other ends to a lug of 50k trim pot, then another leg of the trim pot back to the open R16 & R17 pads?



What would I do? I would get 2 75k ohm, 1/8w resistors. I’d attach each of them to the outside lugs of a 50k trim, along with a clipped lead attached to the wiper. 

Find the junction of R16/17. There will be two acceptable pads to attach the wiper to.   Attach the 1/8w resistors to the other ends of R16/17.


----------



## Big Monk

Harry Klippton said:


> 😚😚
> View attachment 25302



A stock ElectroVibe is like a stock Valve Junior: There are only a few things you HAVE to do to get it to sound great. 

Honestly, Unity Gain and faster max speed are the only things that really beg to be done. It’s awesome with just that.


----------



## joelorigo

Big Monk said:


> There’s a lot to unpack here. I’ll do my best.


You did great thank you! Yes those component swaps are easy to grasp.



Big Monk said:


> What would I do? I would get 2 75k ohm, 1/8w resistors. I’d attach each of them to the outside lugs of a 50k trim, along with a clipped lead attached to the wiper.
> 
> Find the junction of R16/17. There will be two acceptable pads to attach the wiper to.   Attach the 1/8w resistors to the other ends of R16/17.


What is the "junction?" Is the wiper the center lug of the trimmer? As in:


----------



## joelorigo

Big Monk said:


> A stock ElectroVibe is like a stock Valve Junior: There are only a few things you HAVE to do to get it to sound great.
> 
> Honestly, Unity Gain and faster max speed are the only things that really beg to be done. It’s awesome with just that.


Good to know!


----------



## Big Monk

joelorigo said:


> You did great thank you! Yes those component swaps are easy to grasp.
> 
> 
> What is the "junction?" Is the wiper the center lug of the trimmer? As in:



R16/R17 is a voltage divider. 

The phase mix trimmer, along with the fixed resistors, replaces this divider.


----------



## joelorigo

Big Monk said:


> R16/R17 is a voltage divider.
> 
> The phase mix trimmer, along with the fixed resistors, replaces this divider.


Oh I see. Thanks! I was wondering about how to physically implement the mod. Maybe I'll skip this one if it doesn't make a noticeable audible difference.


----------



## Big Monk

joelorigo said:


> Maybe I'll skip this one if it doesn't make a noticeable audible difference.



It does. Worst case, just tack in the assembly and then use fixed resistors of the values:

New R16 = 75k + Rleft
New R17 = 75k + Rright

Where Rleft and Rright are the values measured from wiper to left lug and wiper to right lug after you’ve found the best null setting (strongest phase tone).


----------



## joelorigo

Big Monk said:


> It does. Worst case, just tack in the assembly and then use fixed resistors of the values:
> 
> New R16 = 75k + Rleft
> New R17 = 75k + Rright
> 
> Where Rleft and Rright are the values measured from wiper to left lug and wiper to right lug after you’ve found the best null setting (strongest phase tone).


Oh It does? Hmm. I'm just not knowledgeable about the basics to understand what to do here.

In post #97 you said to build this (pic attached) then "Find the junction of R16/17." I don't know what "find the junction" means.


----------



## Big Monk

On the unmodified ElectroVibe board, R16 and R17 form a voltage divider:





On this drawing, their junction is at Vout. On the board, the wiper of your phase trim assembly would connect at this junction. 

It sounds like you should just try the stock circuit until you get your “sea legs”. 

The Electrovibe really isn’t a beginner project.


----------



## joelorigo

Yeah, I’m going to skip this mod. The others I am interested in are just component swaps (other than the speed LED thing we talked about earlier today) so I’ll do those.  Again, thanks for all your help!


----------



## Feral Feline

joelorigo said:


> I see, thank you. Like this one then?
> View attachment 25293


Switch numbering ❓
3 5 6
2 4 7
1 4 8
⁉️


While the connections you've drawn will work, generally speaking the lugs on a 3PDT are typically numbered thusly:

1 4 7
2 5 8
3 6 9


I only bring it up because it may help in future communications with other builders about circuit wiring etc.


----------



## joelorigo

Feral Feline said:


> Switch numbering ❓
> 3 5 6
> 2 4 7
> 1 4 8
> ⁉️
> 
> 
> While the connections you've drawn will work, generally speaking the lugs on a 3PDT are typically numbered thusly:
> 
> 1 4 7
> 2 5 8
> 3 6 9
> 
> 
> I only bring it up because it may help in future communications with other builders about circuit wiring etc.


Yes, thank you, I noticed that numbering was not normal, I was copying the numbering from a post earlier in the thread (#33) who was addressing the same topic but wasn't sure why it was different.


----------



## markuus

Has anyone done any of these mods on the Electrovibe Mini by chance? As @Big Monk noted in a different thread, the capacitors and resistors are numbered the same way across the two versions, but the transistors are numbered differently.

I'm a bit stuck planning out an upcoming Electrovibe Mini build because I'm not sure which transistors to swap out.


----------



## Big Monk

markuus said:


> Has anyone done any of these mods on the Electrovibe Mini by chance? As @Big Monk noted in a different thread, the capacitors and resistors are numbered the same way across the two versions, but the transistors are numbered differently.
> 
> I'm a bit stuck planning out an upcoming Electrovibe Mini build because I'm not sure which transistors to swap out.



I haven’t dug into yet as I’ve got other projects ahead of it. 

Honestly, the transistor mods are likely to be the least value of all of them. If you’re in a pinch, just skip them.


----------



## markuus

@Big Monk All good, just checking. I'm also probably not going to build this for a while, but I was buying some parts for this and a few other builds and so was looking at these mods and taking note of what I wanted to do for future reference. I grabbed the alternate transistors for this project in my last Mouser order.

I'll poke around on here again when I get around to actually building this. Maybe someone will have figured this out or the EV Mini schematic will be available by then. Not too stressed about it.

Thanks!


----------



## markuus

@Big Monk Actually realized I could figure this out and poked around checking continuity on the ElectroVibe Mini boards. I think I identified the counterparts to Q3, Q4, and Q14.

*Reliability mod (2N3904)*
Q13 and Q14 on the EV Mini LFO board seem to correspond to Q3 and Q4 on the "regular" EV board. I found continuity between the lamp, Q13, Q14, R26 and the Gain trimmer in the Lamp Driver section.

*Darlington mod ( MPSA13)*
Q10 on the EV Mini audio board seems to correspond with Q14 on the regular EV. There's continuity from Q10 with R27/C20, R56, and C28.


EDIT:
Also just noticing the parts list doc calls the transistors on the LFO board Q1-Q4, but those are actually Q11-Q14 as noted on the PCB diagram on the product page for the ElectroVibe Mini here: https://www.pedalpcb.com/product/pcb448/


----------



## ptone

@Big Monk Thanks for posting these mods. Unity gain and max speed mod worked perfectly for me. I used 2.2m on R4, and 2.7k on R14/R15.


----------



## The Gator

Hey thank you for posting all of these mods and the great high lighted sections and details!
I  am getting ready to start building mine.
I was wondering what some of you used for your  sheild around the bulb and the LDRs? Some sort of small plastic cap or?

Thank you
~ Gator


----------



## zgrav

The Gator said:


> Hey thank you for posting all of these mods and the great high lighted sections and details!
> I  am getting ready to start building mine.
> I was wondering what some of you used for your  sheild around the bulb and the LDRs? Some sort of small plastic cap or?
> 
> Thank you
> ~ Gator


I think I used a screw-on cap from a 2 liter soda bottle.


----------



## Big Monk

Unless you are going to use a cap that has an inner reflective surface, you only need the cap for setting the pedal up. Use any old hodge-podged thing for setup then chuck it.


----------



## The Gator

Thank you for the replies. 
I am looking at the different mod schematics posted early in this thread and noticed in the analog LFO portion of the circuit. one schem shows a darlington in place Q1 and Q2 (or a darlington in each position?). The other schem does not show this. 
Any help would be appreciated.
Thank you
~ Gator


----------



## The Gator

Nevermind. I think I understand now.
Different question: if you mounted the LDRs and the bulb on the other side of the circuit board, you could put a red lens there and change the trim pots out for surface pots to dial in the the bias and gain. The question being, any body think of a reason this wouldn't work?


----------



## Big Monk

The Gator said:


> Nevermind. I think I understand now.
> Different question: if you mounted the LDRs and the bulb on the other side of the circuit board, you could put a red lens there and change the trim pots out for surface pots to dial in the the bias and gain. The question being, any body think of a reason this wouldn't work?



As long as there is no light pollution from outside the enclosure then it should work. 

I don't see a pressing reason to have the lamp controls external though but I did contemplate for a time.


----------



## The Gator

Oh. I guess I totally missed what the extra pots are on your original build.
I like the simple rate led mod.
I just thought about doing the flip side install before I saw your rate led mod.
I think I will look at the data sheet for the P9203 LDRs i have for the project to see there sensitivity to different colors orvif they "see" the whole visible spectrum  equally.
That would dictate whether or not to bother with flip side mounting or just do the rate led mod.


----------



## The Gator

Well, they are extremely  broad spectrum LDRs, so leakage of light would be a problem. Unless a purple lens was used.  Also physically having the bulb on the flipside means spacers would be required on the pots for installation to bring the board lower. This makes for a tighter install in the recommended 1590BB.
This makes the rate led mod look like a easier/better idea. 
I probably need to just calm down and build the pedal. ..lol
Not sure I'm  gonna change out a lot of the caps. Probably just do the various resistor based mods.
Thank you for your help and for this information.


----------



## Dman

I've discovered that a cap to a chapstick fits snuggly over my LDR array.

My build couldn't fit any tighter in a 1590bb. After grinding down the base of my dual pot the bulb barely touches the lid. Wish I'd used a 1590bbs or Gorva.

 So . . .   I think I need to do the the Keen stereo mod.(http://www.geofex.com/Article_Folders/univibe/univtech.htm)  But I've run out of room for another 1/4 inch jack.  I'm wondering if I use a stereo output jack will it damage the circuit or alter the sound if I plug a mono jack into it?

I could use a 3.5 mini stereo jack instead.

Thanks for any words of wisdom,

Don


----------



## The Gator

I could use some opinions of those who know more than me.
In the lamp driver portion of the circuit R22 and r26 are on both sides of the bias pot and are 47k. I just ran out of 47k but for some reason I have 51k and 43k. So the questions are, if you could replace these with 51k or 43k would it be a problem and which one would you use? Basically you are increasing or decreasing the total overall by 8K in that portion of the circuit.

Thank you in advance for your help.
~ Gator


----------



## Dman

I'm not a EE, but those two resistors look like they form a voltage divider circuit to me. I think as long as they are kept the same the voltage is divided evenly. I'd go with 51K.

I think the bias is adjusting the voltage difference between the base and the collector of Q4 so that the base of Q3 gets the right amount of signal to effectively modulate the lamps access to ground.

You could also put two 95k in parallel to create 47.5k. 

Hope this helps,

Don


----------



## andare

I'm putting together my build.

The mod for slower speeds is changing the value of R12 from 2M2 to >5M or exactly 5M?
All I have is 4M7 and 5M6. Which one should I go for?


----------



## andare

Bumping this up because I'm too dumb to choose for myself. Is R12 supposed to go above 5M Ohm for slower speeds? If so, am I good to go with 5M6?

Thanks


----------



## Big Monk

andare said:


> Bumping this up because I'm too dumb to choose for myself. Is R12 supposed to go above 5M Ohm for slower speeds? If so, am I good to go with 5M6?
> 
> Thanks



I think changing the middle cap in the LFO string from 1u to 2.2u has a greater affect, per my conversations with @Chuck D. Bones 

Just make sure the caps in that LFO string are tants or film.


----------



## The Gator

When you say "middle" cap in the lfo circuit, do you mean C8?


----------



## Big Monk

The Gator said:


> When you say "middle" cap in the lfo circuit, do you mean C8?



Don’t remember the designator but the one in parallel with the diodes.


----------



## andare

Big Monk said:


> I think changing the middle cap in the LFO string from 1u to 2.2u has a greater affect, per my conversations with @Chuck D. Bones
> 
> Just make sure the caps in that LFO string are tants or film.


Like this?


----------



## Big Monk

andare said:


> Like this?
> 
> View attachment 34225



Yup.


----------



## andare

Big Monk said:


> Yup.


I just checked and I have tantalums in those values! So I'll use those and keep R12 stock at 2M2.

Thank you Derek!


----------



## joelorigo

andare said:


> Like this?
> 
> View attachment 34225
> 
> 
> Big Monk said:
> 
> 
> 
> Yup.
Click to expand...

Cool! This mod wasn't listed at the beginning of this thread when I built mine - I did change R12 to 5M and I have 1u electrolytics in C7-8. What would be change in sound by 1) changing C8 to 2u2 or 2) just replacing with tantalum or film? Slower available speed than stock?


----------



## andare

joelorigo said:


> Cool! This mod wasn't listed at the beginning of this thread when I built mine - I did change R12 to 5M and I have 1u electrolytics in C7-8. What would be change in sound by 1) changing C8 to 2u2 or 2) just replacing with tantalum or film? Slower available speed than stock?


Where do you guys find 5M resistors? All I can find is 4M7 and 5M6. I suppose the higher the value the slower the LFO can go?


----------



## joelorigo

andare said:


> Where do you guys find 5M resistors? All I can find is 4M7 and 5M6. I suppose the higher the value the slower the LFO can go?


I think I got mine from a local shop that is more expensive but usually has what Tayda is out of, or not the brand I prefer. It's highly possible that mine was a 5M6 also.


----------



## The Gator

So have any of you swapped out the series and/or bootstrap capacitors in the circuit as suggested by RG Keen?
If so, did it sound better to your ears? More like a phaser on the chorus?
Just curious as i am thinking of trying it because I plan on opening mine back up and putting some MLCC or tantalum caps in at C7 C8 and C9 in the LFO circuit.

Thank you for your input.
Gator


----------



## The Gator

I changed out the LFO circuit caps for tantalum. I put a 2.2 uf in the C8 position. I  noticed that not only did it lower the lowest speed available, it seems to have shifted the the full range slower. Meaning the fastest speed available isn't as fast as it was and it no longer "tops out" the bulb causing it to stay on.
I originally did the slow speed mod of a 5M1 ohm resistor at R12, and 2K7 resistors at R14 and R15 for the high speed mod. At highest speed setting, the bulb would end up staying on.  I changed out R14 and R15 for 3K9 resistors and it still just barely stayed on if left at that highest speed setting.
Now that i have a 2.2 uf at C8 along with the 5M1 at R12, it no longer goes fast enough to stay on.
This is the most interesting pedal I have built so far.


----------



## Big Monk

The Gator said:


> I changed out the LFO circuit caps for tantalum. I put a 2.2 uf in the C8 position. I  noticed that not only did it lower the lowest speed available, it seems to have shifted the the full range slower. Meaning the fastest speed available isn't as fast as it was and it no longer "tops out" the bulb causing it to stay on.
> I originally did the slow speed mod of a 5M1 ohm resistor at R12, and 2K7 resistors at R14 and R15 for the high speed mod. At highest speed setting, the bulb would end up staying on.  I changed out R14 and R15 for 3K9 resistors and it still just barely stayed on if left at that highest speed setting.
> Now that i have a 2.2 uf at C8 along with the 5M1 at R12, it no longer goes fast enough to stay on.
> This is the most interesting pedal I have built so far.



It should be noted that lower the low range does indeed shift the WHOLE range down. 

So anyone tweaking that should make sure you tweak your maximum fast speed accordingly.


----------



## joelorigo

The Gator said:


> I changed out the LFO circuit caps for tantalum. I put a 2.2 uf in the C8 position. I  noticed that not only did it lower the lowest speed available, it seems to have shifted the the full range slower. Meaning the fastest speed available isn't as fast as it was and it no longer "tops out" the bulb causing it to stay on.
> I originally did the slow speed mod of a 5M1 ohm resistor at R12, and 2K7 resistors at R14 and R15 for the high speed mod. At highest speed setting, the bulb would end up staying on.  I changed out R14 and R15 for 3K9 resistors and it still just barely stayed on if left at that highest speed setting.
> Now that i have a 2.2 uf at C8 along with the 5M1 at R12, it no longer goes fast enough to stay on.
> This is the most interesting pedal I have built so far.


Good to know! That is exactly how mine behaves. I think I'll try this. Is the fastest speed pretty fast in your opinion?


----------



## andare

The Gator said:


> I changed out the LFO circuit caps for tantalum. I put a 2.2 uf in the C8 position. I  noticed that not only did it lower the lowest speed available, it seems to have shifted the the full range slower. Meaning the fastest speed available isn't as fast as it was and it no longer "tops out" the bulb causing it to stay on.
> I originally did the slow speed mod of a 5M1 ohm resistor at R12, and 2K7 resistors at R14 and R15 for the high speed mod. At highest speed setting, the bulb would end up staying on.  I changed out R14 and R15 for 3K9 resistors and it still just barely stayed on if left at that highest speed setting.
> Now that i have a 2.2 uf at C8 along with the 5M1 at R12, it no longer goes fast enough to stay on.
> This is the most interesting pedal I have built so far.


I've soldered all the resistors minus R12. Can't decide if I should leave it stock at 2M2 or go up. I have 4M7 and 5M6, no 5M1.
I also want to use 2u2 for C8. Should I raise R14 and R15 from 2k7 to 3k9?


----------



## joelorigo

Big Monk said:


> So anyone tweaking that should make sure you tweak your maximum fast speed accordingly.


Are you referring to changing the R14/R15 values on the mod sheet at the beginning of this thread (from 4K7 to 1.2-2.7k)?


----------



## The Gator

I have to say if I were to do it again, I would first put in the 2.2 cap at C8 and a 5.1 Meg resistor at R12, then probably socket the R14 and 15 resistors to try and see what will work and give me the fastest speed without topping out and making the lamp stay on. It kind of trips my OCD when the highest speed setting makes the lamp stay on and you get no effect. I have 3.9k as of right now on R14 and R15 resistors. This gives pretty decent speed. I would try the 2.7k IF, you have a 2.2uf at C8 and a 5M1 at R12


----------



## Big Monk

Once I build my Monk Face, a semi original circuit, I should revise the mod thread.


----------



## The Gator

I did the unity mod at R4, the darlington mod at Q14, the reliability mod at Q3 and Q4, the low range mod at R12 and C8, the high speed mod at R14 an R15. then the 50k trim pot with 68ks at R16 and R17, and the 10uf mod on the series caps. Oh and tantalum on C7, 8 and 9.
I did my lights slightly a little different. I noticed that I could wire the rate led set up on both sides of the R19 resistor, and then I put it in place of the speed led. Basically because it shows speed. Then i used  dpdt switch on the chorus/vibe switch so I  could do the bicolor to indicate chorus or vibe settings.

I  had a lot of fun building this and it sounds pretty awesome!


----------



## Big Monk

The Gator said:


> I did the unity mod at R4, the darlington mod at Q14, the reliability mod at Q3 and Q4, the low range mod at R12 and C8, the high speed mod at R14 an R15. then the 50k trim pot with 68ks at R16 and R17, and the 10uf mod on the series caps. Oh and tantalum on C7, 8 and 9.
> I did my lights slightly a little different. I noticed that I could wire the rate led set up on both sides of the R19 resistor, and then I put it in place of the speed led. Basically because it shows speed. Then i used  dpdt switch on the chorus/vibe switch so I  could do the bicolor to indicate chorus or vibe settings.
> 
> I  had a lot of fun building this and it sounds pretty awesome!



Nice!

Can you explain your RATE LED setup in more detail?


----------



## The Gator

Yes! So if you look at the junction where the LFO and the lamp driver circuits meet, you have several components there that are all one point. The emitter of Q2, the positive side of C14, the speed pots and R19. R19 is the only component that the other side of it goes to ground. Which is the other conection you need for the rate led mod.
So I smashed the leads of the R19 4K7 so as to squeeze a lead of a 6K8 resistor in with R19 in the hole that is the "junction" side. Then smashed the lead of a 10K resistor and slipped it in to the ground side hole of R19. The add heatshrink. Then solder the led so as to be parallel to the 10K and in series with the 6K8.


----------



## Big Monk

The Gator said:


> Yes! So if you look at the junction where the LFO and the lamp driver circuits meet, you have several components there that are all one point. The emitter of Q2, the positive side of C14, the speed pots and R19. R19 is the only component that the other side of it goes to ground. Which is the other conection you need for the rate led mod.
> So I smashed the leads of the R19 4K7 so as to squeeze a lead of a 6K8 resistor in with R19 in the hole that is the "junction" side. Then smashed the lead of a 10K resistor and slipped it in to the ground side hole of R19. The add heatshrink. Then solder the led so as to be parallel to the 10K and in series with the 6K8.



Yours just seemed much brighter than my original. Maybe it was the different color.


----------



## The Gator

I really like the warm white LED for the application. Where did you end up soldering your ground for the rate mod?


----------



## Big Monk

The Gator said:


> I really like the warm white LED for the application. Where did you end up soldering your ground for the rate mod?



I don’t remember honestly. I’ll have to experiment with various LEDs.


----------



## andare

The Gator said:


> I did the unity mod at R4, the darlington mod at Q14, the reliability mod at Q3 and Q4, the low range mod at R12 and C8, the high speed mod at R14 an R15. then the 50k trim pot with 68ks at R16 and R17, and the 10uf mod on the series caps. Oh and tantalum on C7, 8 and 9.
> I did my lights slightly a little different. I noticed that I could wire the rate led set up on both sides of the R19 resistor, and then I put it in place of the speed led. Basically because it shows speed. Then i used  dpdt switch on the chorus/vibe switch so I  could do the bicolor to indicate chorus or vibe settings.
> 
> I  had a lot of fun building this and it sounds pretty awesome!


Very nice!

Even though I doubt I'll ever adjust the speed while playing, I still want a visual cue as to which Speed knob is active so I will do the bi-color LED mod. It would be just perfect if this LED could also blink with the rate!

BTW maybe I missed it but I don't think the Darlington mod has been explained other than "it drives the output better".
As a newbie I barely know what a Darlington is (a pair of transistors mashed together in one package?) let alone understand what it does to this circuit.

As for subbing in 10uF caps, does the Electrovibe sound thin without them? I'd rather avoid soldering, desoldering and soldering again several components if it ends up sounding thin or boomy. That's a surefire way for me to ruin a PCB


----------



## The Gator

Honestly  do not know the answer to that Andare. Normally, I either bread board a circuit first to try mods, or put sockets in the board where i want to try different values.
I  wasn't about to bread board the electrovibe. I  just made a choice that I  like a bit more of a phaser sound. To me it seemed getting the second notch larger but still sound like a univibe was the place to start.
As far as the transistor mods go, Big Monk is right. Probably not necessary. Makes no audible difference. I just have a lot of parts I have collected over the years. So I did the mods.
If you want a bicolor speed LED that is a rate LED as well, then you are going to have to wire the speed switch by hand and make some changes. I thought about it, but in the end, I was not feeling that ambitious and liked using the provided switch breakout board a lot. Super easy.


----------



## andare

I want it to sound like a vibe, not a phaser. I'm not in a position to breadboard larger circuits right now, although I know how to. Just gonna socket R12 and use 2u2 for C8 and leave everything else as is. TBH always-on blinking LEDs are annoying


----------



## The Gator

If I  were to do it again, I  would use a 1590BBS for sure. An extra few mm of depth would have been welcomed.


----------



## andare

Yes, a 1590BBS is already in my cart.


----------



## Big Monk

andare said:


> TBH always-on blinking LEDs are annoying



Tie the Rate LED ground to the main bypass switch. That way when you switch off the pedal, the Rate LED turns off as well.


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## Gsatterw

So question for the phase mod on R16/17: what final values are you guys seeing? Are they like a few hundred ohms off of each other or like a few thousand? 

Second question: my electrovibe mini has a really strong effect/depth on the vibrato setting, but seems a bit too subtle on the chorus setting. Will the phase mod likely improve this? I've messed with the bias and offset ad nauseam and am pretty sure I have that as dialed in as possible to maximize the depth.


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## Big Monk

Gsatterw said:


> So question for the phase mod on R16/17: what final values are you guys seeing? Are they like a few hundred ohms off of each other or like a few thousand?



I’ve never measured. The few I’ve built and sold were tuned by ear with trimmer. 


Gsatterw said:


> Second question: my electrovibe mini has a really strong effect/depth on the vibrato setting, but seems a bit too subtle on the chorus setting. Will the phase mod likely improve this? I've messed with the bias and offset ad nauseam and am pretty sure I have that as dialed in as possible to maximize the depth.



This is the crux of the issue with the original Univibe circuit. Got the “Chorus” dialed in? Vibrato is weak. Got the Vibrato dialed in? “Chorus” is weak. 

I’m convinced that they looked at the circuit while designing and just threw the switch in there because, why not?

The Vibrato effect on the Univibe is not that good on its best day so you have to either put the lamp controls up top or just suffer.


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## Gsatterw

Gotcha. So do you think to improve the chorus side I should perform the mod or keep trying to tune the lfo?


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## Big Monk

Gsatterw said:


> Gotcha. So do you think to improve the chorus side I should perform the mod or keep trying to tune the lfo?



Tune the LFO. 100%

You definitely can’t have it both ways, i.e. you can’t have strong vibrato and strong vibe. 

The phase mix is like a last 5% type mod.


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## Gsatterw

Big Monk said:


> Tune the LFO. 100%
> 
> You definitely can’t have it both ways, i.e. you can’t have strong vibrato and strong vibe.
> 
> The phase mix is like a last 5% type mod.


Gotcha. Like I said I've tried everything with the LFO. Anything else I could possibly be missing? Possibly my expectations are out of line.


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## Big Monk

Gsatterw said:


> Gotcha. Like I said I've tried everything with the LFO. Anything else I could possibly be missing? Possibly my expectations are out of line.



You have to tweak the trimmers for a strong  vibe sound while using a light shield.


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## Gsatterw

Does anyone have a good video of their LFO on a pedal they are happy with to give others a reference/starting point of what we should be shooting for? Would be supremely helpful.


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## Big Monk

Gsatterw said:


> Does anyone have a good video of their LFO on a pedal they are happy with to give others a reference/starting point of what we should be shooting for? Would be supremely helpful.



I would do the following:

1.) Set the brightness of the bulb to medium, literally meaning what you deem it’s middle/median brightness 

2.) Install your light shield. 

3.) Tweak the offset/bias trimmer until you get the desired throb/intensity of effect. 

Note: I generally do this with the intensity control maxed.


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## Lukes0n

Hello, i'am tweaking my ElectroVibe build chasing that Throb effect one big difference to original univibe i dont know why they have mistake in both schematic and BOM.... They powering whole signal section trough L75L12 (12V) and it should be by my opinion 15V thats where even schematic is wrong... L78L12 in schem and it shows +15V output from that regulator! So i believe that there should be L78L15.

Next.
I wonder why you use those 2.2uF tantalums ? Wou wont get as much sqeak as bulb is drived ? I thought that tantalums are not much good for audio purposes... https://www.coda-effects.com/2015/04/capacitors-which-one-to-choose.html.


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## Big Monk

Lukes0n said:


> Hello, i'am tweaking my ElectroVibe build chasing that Throb effect one big difference to original univibe i dont know why they have mistake in both schematic and BOM.... They powering whole signal section trough L75L12 (12V) and it should be by my opinion 15V thats where even schematic is wrong... L78L12 in schem and it shows +15V output from that regulator! So i believe that there should be L78L15



There’s not enough of a delta in the supply voltage to properly regulate at 15V using the L78L15. That’s why the L78L12 is used. 



Lukes0n said:


> Next.
> I wonder why you use those 2.2uF tantalums ? Wou wont get as much sqeak as bulb is drived ? I thought that tantalums are not much good for audio purposes... https://www.coda-effects.com/2015/04/capacitors-which-one-to-choose.html.



Leakage is the issue per my talks with @Chuck D. Bones 

You need low/no leakage/residual resistance in the LFO caps for it to work it’s best. 

Also, those caps aren’t in the audio path, they are in the LFO.


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## Lukes0n

Big Monk said:


> There’s not enough of a delta in the supply voltage to properly regulate at 15V using the L78L15. That’s why the L78L12 is used.
> 
> 
> 
> Leakage is the issue per my talks with @Chuck D. Bones
> 
> You need low/no leakage/residual resistance in the LFO caps for it to work it’s best.
> 
> Also, those caps aren’t in the audio path, they are in the LFO.


Yeah, i'm not using LT1054 but step-up module to push 9V 1A in to 18V then trough regulator now 7815 and i noticed biiig improvement in woble. But even that i used L7515 the power consuption is still around 100-120mA. Now i try to swap out those 2n5088 which are probably fake bcs they're all around 650 hfe and original transistors were around 350 hfe.

So if i swap out those for tantalums ill get more silent LFO or whats the deal there ?


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## Big Monk

For those who have done the unity gain mod and are still wishing for a bit more signal:

1.) The traditional Univibe transistor preamp is in fact a discrete opamp. 

2.) It’s overall gain is governed by the classic 1+(Rf/Ri) opamp gain equation. 

3.) For either the Big Electrovibe or the Mini,  this equation would be as follows:

     1+(R2/R5)

Stock gain is ~4.

Here are some values of R2 (3.3k nominal) and their corresponding gain values;

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


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## nkt$275

Thanks Again Big Monk !
Your work on the Electrovibe 
Has been stellar !


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## andare

Can I replace the C100k stereo pots with any other thing?
For the life of me I can't find them anywhere in Europe, let alone find them at a reasonable price since shipping to Poland is around 15 Euros with DHL.


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## szukalski

andare said:


> Can I replace the C100k stereo pots with any other thing?
> For the life of me I can't find them anywhere in Europe, let alone find them at a reasonable price since shipping to Poland is around 15 Euros with DHL.


Retroamplis has them but shipping could hurt:








						16mm stereo pot MIX 90º PCB pins & solder lugs, Ø6.35x15mm full shaft C100K
					

16mm stereo pot MIX 90º PCB pins & solder lugs, Ø6.35x15mm full shaft C100K




					www.retroamplis.com


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## andare

szukalski said:


> Retroamplis has them but shipping could hurt:
> 
> 
> 
> 
> 
> 
> 
> 
> 16mm stereo pot MIX 90º PCB pins & solder lugs, Ø6.35x15mm full shaft C100K
> 
> 
> 16mm stereo pot MIX 90º PCB pins & solder lugs, Ø6.35x15mm full shaft C100K
> 
> 
> 
> 
> www.retroamplis.com


I was just on that website but I vwas looking at Alpha pots because a search came up empty. I have a bunch of things to buy from them already so no biggie. Thanks, my Electrovibe might finally come to life after all.


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## joelorigo

These are the one's that I bought:








						16mm Dual Gang Potentiometer - Short PCB Leg
					

Top Quality Parts for Guitar Effects Pedals and DIY Music Devices. Knobs, Pots, Switches, Kits, LEDs, Enclosures, Jacks, Wire, Resistors, Capacitors, Semiconductors




					stompboxparts.com
				




Would it be more economical for someone to buy them and mail them to you? I'd do it for whatever the actual cost is.


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