How do I mod the speed of the "rate" knob on a Behringer UV300 vibrato pedal

[gandalf]

Hi. I am a complete novice to modding pedals. I just bought a dirt cheap Behringer UV300 pitch vibrato pedal, and I like the sound of it except for one thing, the slowest setting for the rate on it is not slow enough. The pedal is more designed for people who want to have sort of an auto whammy bar sound, I bought it to get a slower effect, sort of like how a guitar would sound on an old tape. I want to make it slower without changing the overall sound of the pedal. How would I do this? Any advice would be very much appreciated.   


Here is a demo of the pedal as an example.
http://www.youtube.com/watch?v=gtHm9AfFpQE

[smallbearelec]

According to this thread at the Other Forum:

http://www.frxxstompboxes.org/viewtopic.php?f=11&t=19067

a guy did what you are asking for by putting a larger capacitor in parallel with the one that controls the LFO rate. It does not look like a difficult mod. If you inquire there, you can probably get some directions. I have the parts that you would need.

http://www.smallbearelec.com/servlet/StoreFront

[gandalf]

link doesn't work?

[gandalf]

never mind got it working. thanks a mil

[Benoi31]

I know this is an old thread, but still one of the first that pops up on Google.
I just did a full tutorial to make this mod yourself and I think it could be very useful to people landing here:
http://www.coda-effects.com/2018/01/modding-behringer-uv300-vibrato-tutorial.html

I also made a short "before/after" video that shows the effect of the mod:

[Mark Hammer]

Nice tutorial (although I suppose you could have used smaller ceramic caps to make it easier to fit back together).

One of the things to keep in mind about vibrato is that, at the sorts of speeds that are still effective for flanging, chorus, and phasing, the small pitch changes produced become virtually imperceptible.  The same is pretty much true of uni-vibes as well, even though they are a different category of circuit.  Subtler changes generally require faster speeds, just as faster speeds generally urge us to turn down depth.

But yes, with the caveat that surface-mount circuit boards are an absolute bear to mod, and a bigger bear to reverse-engineer and find the components you're looking for, Behringer pedals make a nice platform to explore mods to "classic" pedals you wouldn't otherwise dream of messing with.

[clintrubber]

I just did a full tutorial to make this mod yourself and I think it could be very useful to people landing here:
http://www.coda-effects.com/2018/01/modding-behringer-uv300-vibrato-tutorial.html

Thanks for the nice & clear description!

Do you perhaps also know the location of the cap that influences the rise-timeconstant?
In the original VB-2 that is C26 (6.8 uF/16V), and while the UV300 already seems to use 10uF, it might be increased a bit further to my taste,
so in case you know it's (equivalent) location in the UV300 already... ?
(Haven't opened up my UV300 yet to look for it myself)

Thanks!