# This Univibe schematic - What part would you change to brighten up the tone



## nznat (Sep 22, 2022)

This pedal plan and build works great mostly, but the vibe tone is more on the deep and darker side mostly, i cannot seem to get to the brighter aspects of the vibe throb? any suggestions or components on this schematic anyone sees that could be changed or adjusted? Or is it mostly based on the bulb and LDRs ?. Also,  The mini tuning pot is at its limit, cant turn anymore, so don't know what would happen if i had more adjustment in that direction, yet the best tone is back a tiny bit, so that tells that tail. I went into a local store with this vibe build. I plugged it in side by side with a dunlop jimi hendrix univibe, and the dunlop had that brighter squishy / chewy tone, nice, yet my build with the proper bulb etc was way more organic sounding, yet the brighter chewiness was missing from my pedal. I couldn't get the brightness. if i can get there, the pedal will be epic. help!


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## Big Monk (Sep 22, 2022)

Some housekeeping:

1.) It’s generally considered bad form to post the same request/questions in multiple threads. It causes confusion, with people responding back in both.

2.) In your previous post about the bulb issue, you said you’ve assembled three of these SMD Univibe boards and they sounded fine. Did you do something different on this one?

3.) I’ve seen you post 2 different schematics now. Which schematic represents the pedal in question?


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## mdc (Sep 22, 2022)

Increase R3 (47K) to something much larger, like 4.7M.


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## nznat (Sep 22, 2022)

mdc said:


> Increase R3 (47K) to something much larger, like 4.7M.


Does that increase brightness overall? for the preamp, , or only for the top part of the sweep of the throb? as it seems its position is not within the management of the bulb sweep, more so just at the input. ill try it though. much appreciated for any info


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## nznat (Sep 22, 2022)

nznat said:


> that increases brightness overall, for the preamp, , or only for the top sweep of the throb?





Big Monk said:


> Some housekeeping:
> 
> 1.) It’s generally considered bad form to post the same request/questions in multiple threads. It causes confusion, with people responding back in both.
> 
> ...


first schematic was the original design, second was my modified version, which only has added relay switching to it. same stock tone components though


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## Big Monk (Sep 22, 2022)

nznat said:


> Does that increase brightness overall? for the preamp, , or only for the top part of the sweep of the throb? as it seems its position is not within the management of the bulb sweep, more so just at the input. ill try it though. much appreciated for any info



It increases the overall output volume and should affect the top end. It's a well known univibe mod.


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## nznat (Sep 22, 2022)

Big Monk said:


> It increases the overall output volume and should affect the top end. It's a well known univibe mod.


i found 2meg was really nice. you lose a bit of bass. i think a mini switch with something like 3 different resisters would be nice option eh. thanks for the info.


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## Big Monk (Sep 22, 2022)

nznat said:


> i found 2meg was really nice. you lose a bit of bass. i think a mini switch with something like 3 different resisters would be nice option eh. thanks for the info.



Just turn the volume down. You dont need a switch. What you are hearing is boost past unity gain on the volume control.


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## nznat (Sep 22, 2022)

Big Monk said:


> Just turn the volume down. You dont need a switch. What you are hearing is boost past unity gain on the volume control.


nah current the volume / gain control gives a different effect. the change of the resister actually gave high mids, NOT brightness actually. clearly mids have increased from the resister change. And using my volume control thats already there, it only changes the volume, no brightness changes.


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## Big Monk (Sep 22, 2022)

nznat said:


> nah current the volume / gain control gives a different effect. the change of the resister actually gave high mids, NOT brightness actually. clearly mids have increased from the resister change. And using my volume control thats already there, it only changes the volume, no brightness changes.



It’s no different than changing the output resistor in a Fuzz Face. 

More output = More Mids.

Good luck.


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## nznat (Sep 22, 2022)

Big Monk said:


> It’s no different than changing the output resistor in a Fuzz Face.
> 
> More output = More Mids.
> 
> Good luck.


but we were talking about brightness. thats what i was asking. didnt want more mids.


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## Dman (Sep 30, 2022)

I'm wondering if you have read Keen's analysis of the vibe circuit.
(http://www.geofex.com/Article_Folders/univibe/univtech.htm)

Also, Madbeans input buffer mod might be what your looking for.
 (https://www.madbeanpedals.com/projects/_folders/FilterMod/pdf/HarbingerOneFive.pdf)


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