Blog - Overview

Blog - Overview

Wednesday, October 22, 2014

Building a Univibe Clone


This post is like a how-to-guide for a Univbe-Clone. I described what parts I used in my build, where I ordered it from, what mods I added, etc

Since there is currently no complete DIY kit for univibe-like-curcuits, you have to order all necessary parts by yourself. This post is a guideline for this. Remember: its not the only possible way. There are many different ways how to build a univibe and of course its possibel with different parts.

Note: Consider also that building the univibe takes a lot of time and debugging is not easy.

Very interesting article how the univibe works, can be found at GeoFex:

Univibe Projects

First you have to choose which project and PCB you want to use. Currently there are two different projects for a univibe like build:

  1. Neovibe (General Guitar Gadgets)
    PCB can be purchased from GGG (General Guitar Gadgets) here:

    Guide for the Neovibe-Project:
  2. Harbinger One (MadBeanPedals)
    The Harbinger One PCB can be ordered from madbeanpedals here:

    Description for this project:
 I would recommend the HarbingerOne, because it has some advantages:
  • 9V voltage option is already considered on the PCB (curcuit including the LT1054 for voltage doubling), powering with 18V is also possible
  • Includes an extra input buffer option (input buffer can be selected with extra switch: Modern <-> Vintage) 
  • Gain Control for the Lamp additionally to the offset
  • LED socket on the board (LED blinks in same speed as the lamp)
  • Pots and switches can be mounted directly to the PCB board
  • PCB is little bit smaller
The Neovibe PCB represents the classic vintage curcuit only. Some exclusive features of the Neovibe
  • Features footprints for a rectifier bridge. This enables the Curcuit be power by AC voltage also , DC voltage is still possible (20-14V AC, 18-24V DC)
    Still for powering it with 9V DC, a additional board with a voltage doubler has to be added, since the Univibe needs at least 18V DC
  •  TO92 and TO220 footprint for the LED Driver transistor (harbingerOne has only a TO92 footprint, but using a TO220 transistor is not necessary in my experience)
Note: My step-by-step description always uses the Harbinger One Project as basis. There will be some references to the Neovibe also.

Order the parts...

Where do you get what parts

Order either at GGG (Neovibe) or madbeanpedals (HarbingerOne). See above.   

Electronic parts, Enclosure, Pots...
This is where I ordered all the electric parts (caps, resistors, transistors, diodes, sockets), pots, switches, the enclosure, pot knobs ...
Even the dual audio pot for the speed is available there. 

Lamps & LDRs
The Lamp & LDRs for the univibe has to be ordered somewhere else.
Sources where you get these: (Germany) (US)

Both offers great lamps & LDRs for the univibe.


What to order? 

Order all the parts listed in the BOM in the Harbinger One Document (or in the Neovibe doc).
Additionally following parts are necessary

  • MPSA13 Transistor (as LED driver)
  • Inline socket & DIP8 socket (for socketing some transistors, resistors, lamp and IC)
  • Dual color LED with common anode
  • 5mm LED Bezel holder
  • 2x DPDT switches for input buffer and chorus/vibrato (instead of one SPDT and one DPDT switch)
  • LED driver transistor (I used 2n5088)
  • DC Adapter Jack
  • Input / output jack
  • Enclosure
    The perfect enclosure I used for the vibe, is the C-Type box. its not too large and you have a lot of space:
    Note: this enclosure has to be drilled
  • Solid Copper wire for mounting the light shield
  • PCB standoff mounting pillars (mini)
  • Enough wire for pedal wiring
  • cable straps, duct tape,...
  • Knobs for the pots 
Info: Theres no need for a battery clip. Using a battery for a univibe makes no sense, since it wouldnt last very long.


Assemble & Solder PCB

Assemble the PCB according to the document of the Univibe project. Be careful, always check values of ordererd parts before soldering. 

Note: the harbinger one lists R46 as 47k. According to some builders, it works better with a 4k7!  

When choosing the HarbingerOne, you also have to choose which power option do you want to use. I used the 9V regulated option. So everything has except the filter board has to be assembled. You can also ommit the parts of the filter board, when ordering the parts.

I would recommend using sockets for following parts:
  • Q13 - lamp driver transistor (I recommed using a MPSA13)
    This transistor can get warm, since it needs to handle most current of all transistors. May occur, this one needs to be change someday.
  • Q14 - J201 (I only did it for fun)
  • Lamp - Socket the lamp, so you dont have trouble exchanging it someday
  • R46 (Harbinger) - Its listed as 47k in the BOM, but the effect works better with a 4k7 


True bypass & LED wiring

This is the true bypass wiring for the univibe that I used. I think its the most useful wiring. Others use 2 different leds (one as speed indicator, one for bypass), I used only one LED and it also shows selected mode (Chorus, Vibe).
  • True bypass
  • Lamp switched off, when effect in bypass, to prolong the lamps lifespan
  • 2 Color LED for different modes (Chorus <> Vibrato)
  • LED switched off when effect in bypass 
  • LED blinks in same speed as the LAMP (indicates speed of the Vibe effect) 
  • Grounding effect input when effect is bypassed
To do so, you need a DPDT toggle switch (On - On) for the Chorus/Vibe switch instead of a SPDT.
One row of the switch is for the LED, the other is for the Chorus/Vibe switching and must be wired to the PCB (C/V PCB footprint).

1) Connect the 3rd row of the 3PDT stomp switch as shown in the graphic below. Wire the middle position to ground. One position must be connected to the middle position of the C/V switch, the other position to the Base of the LAMP Driver transistor (Q13). There are printouts for this in the HarbingerOne (Pad directly above R52 in the PCB) and in the Neovibe (CANCEL switch, Pin "X").
2) Connect the two positions of the C/V switch to the 2 cathodes of the dual color LED.
3) Connect the LEDs anode with a resistor (this is that the LED doesnt burn). I recommend a 330R resistor here.
4) Wire the LED resistor to the emitter of the NPN LED driver transistor (i used a 2n5088 for this)
5) Wire the collector of the LED driver to 9V voltage
6) Wire the base of the LED driver transistor to the Pin 1/2 of the Speed pot (SPD 1/2)

If you want to use a standard LED (one color), you only need a SPDT switch for the C/V switch. In this case connect the cathode directly to the 3PDT pin.

Update: The new Harbinger 2015 version already features a driver transitor for the Rate LED. So you can omit steps 3,4,5,6. Connect the Anode of the LED directly to the positive LED pad on the PCB instead. You can use a 10k trimpot between the LED anode and the Pad to control the LEDs brightness.



Speed pot wiring

Speed pot is a dual reverse log audio pot. It must be wired and cant be mounted to the PCB.

 I recommend the wiring shown above, since its the easiest. Pin 1+2 of both pot sides needs all be wired together (additionally also the Base of the LED driver get connected there). 


General Pot wiring 

I didnt mount the Volume / Intensity pots and the toggle switches to the the PCB (HarbingerOne). I wired them all, because I wanted a different arrangement of them on my enclosure.
Anyway its easier to mount them directly to the PCB and also safer (less problems). 


Final Test & Debugging

Before preparing the enclosure and building everything into it, I recommend a final test of the curcuit. The curcuit should be working with no problems. If there are problems, debbuging is easier if the enclosure is not envolved.

Possible problems (Ive experienced):
  • Lamp is on, but doesnt blink (LFO is not working):
    • Wrong wiring of the Speed pot
  • Lamp is off:
    • Q13 is grounded wrong (invalid 3PDT wiring)
    • Bad soldering
    • Transistors soldered wrong way (pinout)
 Debugging is not easy. Multimeter is strongly recommended for this. Check all currents! Good luck

If everything works, you can also setup the OFFSET and the GAIN pot for the Lamp.

Installing the light shield

Theres no perfect instruction for a light shield. Take something that fits. 
In the Neovibe document theres an instruction to build a light shield yourself out of paper.

The light shield can be covered with aluminium foil inside, so that some light gets reflected. In my opinion it doesnt make much difference, since I always point all LDRs directly to the Lamp anyway and I feel that the foil doesnt reflect light that good.

For my current build, I used a Cap of an Axe Deo bottle, cut it down a little bit.

To mount the light shield, solder 4 solid copper wires to the single pinouts beneath the LDRs. These holes have no connection and serve only for mounting purposes.
then install the light shield and wire the coppers together.

Drilling the Enclosure

Since theres currently no pre-drilled enclosure available that fits for a univibe, you have to order one and drill it yourself.
Since the dual pot and the PCB with the light shield required an enclosure with more depth, common enclosures (B and BB types) wont fit.

I recommend the C-Type enclosore (available at Its not too large, but has enough depth, so in my opinion its perfect :)


I attached a drill-plan that I created and used for my vibe enclosure. Its not a direct drill plan, but more a strickle. It can be printed, the squares cut out and then be used for marking the chassis where the holes should be drilled.

First picture is for the upside of the enclosure and marks the place of the 3 pots (1st row with the circles), the switches and the LED (led in the middle, 2nd row) and the 3PDT switch (3rd row, middle).
Second picture is for the backside of the enclosure for the DC adapter jack.

3rd picture is for the Input/Output jack on the side. 

Drilling diameter:
LED Holder & Pots: 8mm
DC Adapter jack: 12.5 mm
3PDT switch: 12mm
Toggle switches: 6mm
Input & output jack: 9.5mm

Note my drilling instruction is just a proposal. You can arrange the parts as you wish (be only careful that there is enough space for everything inside the box).

Painting the Enclosure

My idea was to paint the Univibe logo on the upside of my enclosure.

I used the univibe logo I found in the web.

1) printed the logo in black on transparent-printable-adhesive foil
2) cut the font "uni - vibe" out (with a scissor, took lots of precision, not easy)
3) stick the foil on the enclosure, where I want to have it
4) covered the rest up with duck tape as protection
5) Sprayed on the enclosure with a color spray (use some ground coverage for the floor). Dont hold the spray to close to the enclosure.
6) let the color try and repeat step 5+6 two times again.
7) remove all duck tape and the foil
8) use transparent laquer to protect the sprayed font


So now you can build everything into the enclosure and mount the knobs!

enjoy your vibe :)


Heres a demo of my Neovibe Pedal.

Demo of the the Harbinger One coming soon :)

I wrote this article to share all my experience and ideas with you. I really appreciate some comments below.
if you have any questions you can contact me per e-mail also:


  1. Hi there, just built one and got it working. Interested to know what the benfits are to replacing R46 to a 4k7.

    Great blog, found it extremely useful for my build, thank you for posting.

  2. This comment has been removed by the author.