Modding the Behringer UV300 Vibrato : tutorial

Here is my last ""build", I modded a Behringer UV300 vibrato:

Behringer released a whole series of pedals inspired by not-produced-anymore Boss pedals like the Hyper Fuzz FZ2 (Behringer Super Fuzz 300), the Heavy Metal HM2 (Behringer Heavy Metal 300)...etc. I was really interested in one of them: the Behringer Ultra Vibrato, which tries to emulate the famous Boss VB2.



The Boss VB2 is an analog vibrato that is one of the rarest Boss guitar pedal alongside the mythical Boss Slow Gear SG1. It is today worth around 500 dollars and is really difficult to find. A bit curious about it, I wanted to try the Behringer version.

Behringer does not have the best reputation among guitarists. "Cheap", "fragile", "noisy", "ugly" are the kind of adjectives you often find online about the brand. Indeed, this pedal is very cheap an costs around 25 euros, which is really impressive!

After testing it, I personally think that online reviews were not really doing justice to it; I actually found this vibrato pretty convincing! The buffer modifies a bit the sound, but the vibrato is quite warm and really nice! The Depth knob really allows to have subtle settings, and the "latch" function is quite interesting as well.

Regarding its robustness, I am not really convinced by either the plastic enclosure or the potentiometers that frankly look quite cheap. Maybe a good candidate for a rehouse!

However, there is a big drawback: the speed, even set to minimum, is waaay to high! I am more into subtle background vibratos that improve a clean sound rather that the Leslie effects you can get out of it.

So I decided to mod it to slow it down. Here is a before / after video to show you the effect of the mod:

I am really happy about how it turned out, the pedal is much more usable after this mod. Happy with it, I decided to write this simple tutorial to explain how to do it, step by step. I think it is a good opportunity for beginners to make their first mod. Ready? Let´s go!

What do you need?

No much, really. Here is the list of supplies to make this mod:

• A 30W minimum soldering iron (you can also go for a luxury soldering station :) )
• 60% Sn solder
• Two 100nF film or ceramic capacitors (possible to use 82nF capacitors as well for a slightly quicker setting). The smaller the better! Ceramic are the best for this mod.
• A screwdriver
• Optional: a LED with long legs
• Optional: tweezers

First step: dismounting the pedal

To have access to the circuit we will have to remove the PCB from the enclosure! Do not panic: it is fairly easy.

Start by removing the front pannel screws:

Then remove the bottom plate screws :

You should now be able to unmount the bottom metallic plate and have something like this:

Then, remove the knobs by pulling them gently. They should come off easily.

You can now remove the upper part of the pedal. Do it slowly as there is still the battery clip attached to it:

To remove it, unmount the top switch by pressing on the lateral hinges like this one:

You should be able to remove the lid. You can now remove the battery clip through the right hole:

You should now have all of this on your bench:

In order to separate the PCB from the bottom part, there are three screws to remove. Two of them are located above the jacks:

Lets take some time to observe components here: there is a CoolAudio V3102D, a clock for bucket brigade chips. CoolAudio makes reeditions of old chips that are not produced anymore, but essentials to achieve analog delays, chorus or vibratos: the bucket brigade chips.

Step two: modding the pedal

The UV300 is thus a 25 euros analog vibrato! Impressive! Once you have removed the screws, you can pull the PCB out of the bottom part of the enclosure and turn it around. Here is the full circuit, with lots of SMD parts, including the Bucket Brigade reedition chips of CoolAudio!

I know it is a bit scary to mod that, but do not worry! Our components are relatively big, and you do not have to replace them. They are C12 and C15 that have a 47nF value. To make the vibrato slower, we will solder the 100nF capacitors in parallel. Here are the culprits:

Start by adding a bit of solder on each sides of the capacitors. It will make the next steps easier. Take your time, but do not heat the capacitors too much! Let each solder cool before doing the other one; you do not want to unsolder the capacitors. You should have something like this:

Then, prepare your capacitors. Cut the legs as short as possible, and fold them to have the good lead spacing, fitting with the SMD lead spacing. With my film capacitors, it looked like this:

You can now solder the capacitors. Solder lead by lead, do not heat the components too much; just melt the solder that you added previously.

Same goes for the second capacitor. Try to place them as flat as possible, and verify that there is no false contacts! Another option would be to use wires instead of soldering them directly on the board. You can even use a DPDT switch to make the mod activable at will.

If you want to switch the LED for another color, it is time to do so :). Desolder the old LED with a desoldering pump or wire. You need a long lugs LED. The squarred pad is the negative side of the LED, do not invert it.

  Beware! Unssoldering electronic components is not always easy. If you are begining, I would suggest not to modify the LED. It is only aesthetics so...

Choose carefully !

Step three: putting it back together

Replace the PCB on the bottom part of the enclosure. Verify that it is possible to place the PCB against the bottom plate. If you cannot close it, try to place the capacitors in a different way.

You know the next steps :) Lets put it back together. Take your time and verify that you did everything like before:

There you go! The vibrato is now much more usable. Slower and subtler settings are now possible :)

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