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Mad Bean Pedals Harbinger Two Manual

Fx type: univibe

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Harbinger Two
FX TYPE: Univibe
Just how lazy and inefficient am I? I'll let you pass judgment. I first started working on what would become the "Harbinger
Two" around 2013. I knew I wanted to do a Univibe in a wah configuration, and I knew more or less how it should be done
(mostly less). Enter an endless parade of prototypes over the next 5 years. Mind you, I was not working on this constantly
- every year I would pick it back up and try to get it right. And, with each iteration I ran into some kind of problem. It went
like this: find problem, how to solve? Lemme just work on something else. The problems ranged from not understanding
how to control the LFO speed properly, bad voltages, bad response to speed control, etc, etc. But, I never gave up on it
and eventually I solved all the problems. And, I'm glad I did because this is a really good DIY project.
The Harbinger Two is very much a port of the Harbinger One into an expression control. If you've built the HB1, you can
certainly build the HB2. If you've never built a Univibe, you can certainly build and HB2, as well. But, and I want this to be
very clear: this is a time-consuming project. Expect to spend a few evenings putting it together. It's not something you can
build in a single day and it requires patience and commitment. IOW, go slow and get it right the first time!
Details about the design: The Harbinger Two (like the One) does depart a little from the traditional Univibe design. It
includes an JFET buffer for a louder and brighter input option (the second input option is the stock Univibe). It also runs
all the audio at 18v instead of a regulated 15v. This gives the audio portion a little added headroom at the expense of a
small voltage drop (see the Voltage chart below for an explanation). The LFO section runs from regulated voltage like the
Univibe.
And, like the One, the HB2 only requires a 9v DC supply to operate. Lastly, the HB2 adds a new tweak: the Drag switch,
which creates a ramp down effect with mod rate.
Controls
SPD: The rate of the modulation from fast (toe down) to slow (heel up).
INT: The intensity of modulation.
VOL: Output volume.
C/V: This switch selects between a chorus effect (modulation mixed with dry signal) or vibrato effect (pitch modulation
only).
MOD/VIN: This slide switch selects between the traditional input and a JFET buffer input. The JFET buffer has more out-
put volume and is brighter.
DRAG: This switch creates a slight delay and ramp-down effect of the modulation rate when going from Toe to Heel posi-
tions.
GAIN: This trimmer sets the brightness of the LFO-driven bi-pin lamp.
OFFSET: This trimmer lets you adjust the ramping of the lamp's brightness.
Terms of Use: You are free to use purchased Harbinger Two circuit boards for both DIY and small commercial operations. You may
not offer Harbinger Two PCBs for resale or as part of a "kit" in a commercial fashion. Peer to peer re-sale is fine, though.

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Summary of Contents for Mad Bean Pedals Harbinger Two

  • Page 1 Terms of Use: You are free to use purchased Harbinger Two circuit boards for both DIY and small commercial operations. You may not offer Harbinger Two PCBs for resale or as part of a “kit” in a commercial fashion. Peer to peer re-sale is fine, though.
  • Page 2 Layout...
  • Page 3 Traces There is a layout error regarding Q15. Please see the Notes section for the correction.
  • Page 4 B.O.M. Resistors Resistors Caps Diodes 15v Zener 1N5817 100k 330pF 1N5817 1n914 1n914 100k Transistors 2N5089 Q2 - Q10 2N5088 Q11 - Q13 MPSA13 220n MPF102 100k 220k BS250 Regulator 100k 220k REG1 LM7815 220k 100k 470pF Optical 100k OPTO1&2 NSL-32 100k Illumination...
  • Page 5: Shopping List

    Shopping List Value QTY Type Rating Value Type Rating Carbon / Metal Film 1/4W Zener Carbon / Metal Film 1/4W 1N5817 Carbon / Metal Film 1/4W 1n914 Carbon / Metal Film 1/4W 2N5089 Carbon / Metal Film 1/4W 2N5088 14 Carbon / Metal Film 1/4W MPSA13 Carbon / Metal Film...
  • Page 6: Parts Guide

    AND ICAR pot, jacks, etc. Plus, the wah pot is already mounted which is a BIG advantage. Tip: you do not need to spend a lot on a fancy Wah pot. In the Harbinger Two it only controls the bright- ness of the LEDs in the two NSL-32.
  • Page 7 Notes BS250p Polarity Protection and Correction I chose this method for the HB2 to take advantage of its very low voltage drop. However, I made a mistake in the layout- the transistor orientation is shown incorrectly. Q15 must be flipped around to take full advantage of the BS250p. It will still work the incorrect way but the transistor itself can be damaged by reverse polarity if left in its incorrect orientation (I finally realized this when I fried my own transistor when I plugged the power in backwards).
  • Page 8 Stepped drill bit, Xacto knife, wire cutter and a deburring tool. There is no drill diagram for the Harbinger Two. You need to work it out on you own. I used painter’s tape to mark out four drill locations (two pots and two switches). I set them between the post and jack on the enclosure and spaced them about 1”...
  • Page 9 Light Shield I do hope to be able to include a 3d printed light shield with this project. I may be able to do so by the time the boards start shipping. But, in case it doesn’t work out here is an easy way to make one: 1) water bottle cap, 2) cover it in one layer of painter’s tape, and 3) use a black Sharpie to mask out the tape.
  • Page 10 Wiring This diagram shows the HB2 wiring without an LED and is for a DPDT switch (since that is what many of the Crybaby Wahs come with). You are welcome to use an LED indicator if you want, though. Just use a 3PDT and do the same wiring, adding the LED anode and ground to the extra column.
  • Page 11 Build Pics Note: These pics were taken before I realized Q15 was wrong on the layout, so ignore it.
  • Page 12 14.74 Because the audio portion of the Harbinger Two is unregulated, you may see some small fluctuations on the ~18v rail. This is from the changing current demands of the LFO, as best I can tell (the total current draw does vary some with different speeds). Do not let it con- cern you.
  • Page 13 Schematic...