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Monday, 29 October 2012

Behringer UV300 Rate Mod (Slow Down)

I thought I'd take a quick venture into modifying a effects pedal. The one I chose was the Behringer UV300 ( Ultra Vibrato ) I love Behringer gear and in most cases they do a really good job at effects and pretty well everything they put their minds to (see the X3!)
anyway I bought this on a whim cause it was very very cheap, I didn't even bother looking for samples because if I'm honest there is only so many times one can watch people doing out of tune covers of Lucy In The Sky With Diamonds while reviewing Vibrato pedals - also they never turn the rate down to nothing to show you how slow it goes.

as you can probably tell by this post, the "rate" didn't go as slow as I wanted, I like that sort of hypnotic warped record vibrato which this pedal couldn't do however with a little knowledge of how oscillators work and a bit of time probing around with a scope I was able to modify this to go slow enough

In order to slow down the range of the Rate control you basically just have to add capacitors in parallel with C12 and C15 - or you can swap them completely for higher values - the higher you go the slower it is however you need whatever capacitors you add to be very close in value to each other because if one is very different you get an uneven vibrato.
anyway here are the pictures.

if you have any questions - ask!

and you don't need to rehouse behringer pedals, the plastic is very strong - it easily withstands being dropped down stone stairs many times.

solder very quickly otherwise you'll be resoldering SMD stuff!

it's a good idea to do this in order to tailor it to your preference

the part of the circuit I am changing
The Behringer UV300 with its nice new switch


  1. how would i do this without a switch. im ok with it always being on slo moe

  2. just solder 2 100n caps on top of the 2 that are there, this puts them in parallel with the existing ones

  3. Hey, thanks for posting this mod - I've been after a way to get that woozy tape effect (in hardware) for a live project I'm working on. This should work great, the pedal is pretty cheap to get hold of and I've got a load of caps knocking about, cheers!

    - love Behringer pedals too. They get a lot of stick that comes down to snobbery imo...

    1. there is definitely a lot of snobbery!
      these pedals can take the abuse too very much unlike the EHX pedal I had for 3 days before the switch snapped in it!

  4. Hi. It tried this mod with a 0.1uf Polyester Capacitor (a friend told me 100n converted to that). I was super careful to use minimal solder and only touch the iron to the solder point for mere seconds. Now I am getting no sound out of the pedal when I am in Latch or Unlatch mode. I am pretty disappointed that I may have fried my pedal. It only passes guitar through in bypass mode. Can you tell me what I did wrong? Is there anyway to backtrack and make this work? Thanks, Andrew

    1. I doubt you will have fried it - behringer pedals can take alot of abuse.
      100n is a 0.1uf - that's correct. however 100n maybe a bit too high a value and you should use ceramic capacitors because the part you
      are modifying is the oscillator in the pedal - ceramics are the most stable and stability is what you need for this type of thing.

      if you have cut the 100n caps off and it still isn't working then it will be either a solder whisker shorting something in the vicinity (happens to me alot)
      or the solder joint with the original components has gone bad so you'll need to touch it up a bit.

      if it still doesn't work take some pictures - as clear and as high res as you can get them and I'll have a look

    2. Paul, I got it to work! As it turns out I was using a bad 9v wall wart that I had picked up only a day earlier. The pedal's light went on but somehow my pedal didn't like it.
      My normal pedal board 9v AC got it going.

      I love the slow warbly sound you get from it now. I call it "weepy" guitar. The new caps I put in were bulky and would not allow me to close up the pedal since they were sitting against the circuit board. So I permanently attached two 4" leads to the circuit board and then soldered the new caps onto them. I now have the new caps live in the open cavity under the battery compartment. Thanks again for posting this article. I now have a great effect I have been looking for for less than $30.

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  6. Do you have a mod for a dr600

    1. unfortunately I don't own one and people aren't willing to send me them to experiment with!

  7. Thank you so much!!!

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  10. Hey would you know how to mod the input of the UV300 so that it accepts a Y cable?

  11. Hi this is a really cool and easy looking mod.. However do I use a four connection dpst switch? or a 6 connection?