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.

Saturday, April 25, 2015

Dan Armstrong Blue Clipper

Here's a quicky for your Saturday. The Blue Clipper was one of the small effects units by Dan Armstrong that plugged straight into your guitar output jack. It uses one side of a JRC4558 to produce a basic distortion effect.



6 comments:

  1. how do we add gain control in this?

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    1. my guess would be to replace the 1m resistor with a B1M potentiometer

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    2. That 1M resistor is just the pulldown resistor at the input to reduce footswitch pop. Try replacing the 150k resistor with like a 250k pot.

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  2. It works only according to the original circuit, where the 8.2K resistor is included in the diodes.

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  3. weird that whoever made this layout didn't invert the word Blue Clipper for etching the pcb

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  4. The perf layout is verified. I think you might need to reverse the PCB image if you are etching.

    Since there are a few versions of the schematic, I checked the comments for the effect on the vero site as well as Run Off Groove's archive at home-wrecker.com. I then breadboarded the circuit. Here's what I found:

    -The 20k/240k resistor combo doesn't work. 200k/240k, 22k/27k and 22k/22k work nicely as a distortion. 22k/100k sounds mis-biased and kind of fuzzy, but at least passes sound.
    -With the 2.4k resistor, you will have about unity volume at most. Other people changed the resistor to 150R. I went with a 240R resistor, thinking someone may have misread the value when tracing it. Either 150R or 240R gives plenty of volume.
    -The 33nF cap muffles the sound too much for me. I lowered it to 3.3nF as suggested by Run Off Groove.
    -If you want a tone control you can easily put in a SWTC by replacing the 10k resistor and 33nF cap with a 10k pot with a 6.8nF or so cap from lug 2 to ground.
    -I tried using a 250k pot in place of the 150k resistor, but the guitar's volume knob works well enough as a gain control.

    This circuit sounds pretty good, especially for how simple it is.

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