This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Tuesday, April 2, 2019

JHS Haunting Mids

The JHS Haunting Mids is an EQ circuit that controls the mid frequencies along with giving a 10dB clean boost. From the JHS site:

The Mids and Sweep controls work very closely together so you can find the perfect frequencies to boost or scoop mid frequencies. When the Mids knob is at 12 o'clock, no frequencies are boosted or scooped.  Turning the Mids knob to the left of 12 o'clock will begin to scoop out midrange frequencies, while turning the Mids knob to the right of 12 o'clock will begin to boost midrange frequencies. The Sweep knob controls the what frequencies will be affected.  Sweep knob to the left will cause low-mids to be affected, while Sweep knob to the right will cause hi-mids to be affected.  The Lo/Hi toggle is like a "Q" function and controls how sharp the frequency peak is that you’re affecting with the Mids knob.  "Lo" is a softer and wider peak for slightly subtler affect as you tweak the Mids/Sweep knobs.  "Hi" is a sharper and steeper peak giving you a very pointed and defined effect as you tweak the Mids/Sweep knobs.

Should fit nicely in a 1590B. Schematic for reference.


  1. hy everybody !!
    greetings from austria
    another great layout. i build it last night, and i works from the first time!!
    i used the parts shown above, and it had no problems, low noise, nice sweep, and the "Q" switch works great....

    thanks for your work!!!!!(2 or 3 new layouts every week! what a great job.)
    ( i think you can mark it as verified )


  2. Can we see the schematics as well as the layout?

  3. Hi, thank you very much for the layout of this pedal.

    I really like it and I made one! Well, Almost.. :)

    The one I made is technically working - the guitar signal passes through and all controls are working properly, as expected, but there's a big high-pitch steady screaming noise covering the sound. It get louder when I increase the volume knob on the pedal.
    I'm a newbie, but I'm guessing there's some short circuit causing it?
    Is there any info/guide on how to fix such problems, instead of making (trying) all again from scratch?
    I couldn't find something useful on Google.

    1. Did you box it yet? If not, could just be interference that will likely go away once you build it into an aluminum enclosure.

    2. Actually I tested it only after I boxed it. I found that the pitch of the noise changes when I move the power cable in the DC jack. I changed the DC jack, but it's the same. I will try to run it without the switch - just everything straight to the board from the jacks. I printed the board (printer-iron etching), so I don't expect errors there.

  4. Got the same issue,
    Working and sounds great , but there's that high pitch noise..
    Anyone here solved it?

    1. I gess two chances:

      -Bad IC's (big problems with false ones)
      -Wrong resistor values, need to right click and open in a new tab to see in full resolution.

      Hope it can help.

  5. Hello Mr Storyboardist,

    Could you please post a new link to the schematics? The actual does not work.

    Thanks a lot.

  6. I just built the etched version of this and I get a clean signal but the mid control pots don't do anything. Pretty sure the volume is just bringing it up to unity too.. When I swap out the TL072 nothing changes, when I swap the 5532 other IC's make the sound get super gritty but the pots seem to do a little something..

    Anyone got any ideas? Cheers!

    1. Update - came back with fresh eyes and noticed a solder bridge. Seems to work now - not boxed up with a switch but I can't tell if I am boosting the volume or not yet. The EQ stuff definitely functions though!