Monday, 6 October 2014

Soulkitchen Heavy Darling Fuzz

Wanted to do a quickie, so this seemed like a suitable circuit and we didn't have it on the library yet. Not a lot of info around.. One could play around with the value of that 10µ cap to see how 22µ or even a 100µ affects the tone. Maybe even make it switchable. Either way, this should fit nicely in 1590A.

A friend of mine knew this circuit and recalled asking around for a demo clip. Back in 2008. Now, today, we finally have a demo. Huge thanks to HarmRazorback! Very nice playing man!




34 comments:

  1. Please check the transistor, I think the Q1 must be 180°.

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    1. Nope.
      https://www.fairchildsemi.com/datasheets/MP/MPSA13.pdf
      +m

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    2. You are right, my bad, sorry.

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  2. please: schematic!! I can't find it at FSB

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    1. You could try google and/or DIYSB.
      +m

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    2. Schematic missing in Google, DIYSB, FSB... another idea?

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    3. Draw it from the layout

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    4. One can find it on late pedal geeks united forum. It's Culturejam's drawing. But there is two transistors, 5 caps and seven resistors, so i'm not sure why you would even need it.
      +m

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  3. Verified. It's a loud, more of a distortion like fuzz. The 10µ cap is fine for me. Tested it with a Telecaster.

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    1. Cheers! I'll tag it right away!
      +m

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  4. I assume by replacing the 1k resistor going from Q1's emitter to ground one could add sopme sort of gain control, right? Or would it be better on Q2's emitter?

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    1. Q2 emitter to ground equals to maximum gain. For Q1, the 10µ+1k could be transformed into a gain control. Something like 220R pot would probably work the best.
      +m

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    2. I am thinking about doing this, but want to confirm my though process before doing so.
      Would this mean I have to connect the point of the 10uf cap on the 9th line, the point of the 1k on the 6th line and the ground to a 220R pot? so it changes the amount of throughoutput to ground?
      (so position of 10uf to pin 1, ground to pin 2 and position of 1k to pin 3?)

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  5. Someone should probably record a demo clip with this circuit, since people have been asking for one since 2008...
    +m

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    1. Someone just did... http://www.youtube.com/watch?v=OhS3F1AHscA

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    2. Thanks! I added the video to the post!

      Very nice playing!
      +m

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  6. I built it - mine sounds like many other fuzzes on here. It's bright on chords, though a bit brittle. Not as loud as many (I thought Darlingtons were "supergain" trannys). On lead you get a relatively weak fuzz. There's no headroom at all, initial attack gets clipped and you get a woolly sustain that does not sustain long enough. Sounds better on neck pickup if you want that 'synthlike' tone.

    It does sound decent if you put it in front of the BMP+LPB for an extra gain stage. Then you have to reduce the gain going out of this one, or you overload the BMP, but if you roll off some of the highs with the BMP it sounds pretty sweet.

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    1. MPSA13 has hfe ranging from 5000 to 10000, so it is super gain. But in this circuit it is only driving the second transistor, which is 2N3904. So the gain of Q1 isn't related to output level at all. You could try linear pot for volume to see if it'll give out a better feel for the sweep in terms of output.
      +m

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    2. Just a note that I revisited this effect, and it sounds a lot better than I remembered, It is a high gain pedal for such a small circuit thanks to the darlington.

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  7. I'm new to stripboards, but I'm left with a silly question. I can't find where to wire the output to this board. I've found 9v, Input, Ground, Volume1, and Volume 2... Is there something I'm misunderstanding about this circuit?

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    1. As you can see, there is no "Volume 2" connection anywhere on the board. The volume pot has three lugs/pins. Pins 1 & 3 connect to the board as shown. The note on the bottom of the layout says "Volume 2 to output". So you take a piece of wire and solder the other end to the volume pot's lug/pin 2. The other end of that wire is your output.
      +m

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  9. It's crisp, stacks well with other distortions and is good on it's own for rhythm parts.

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  10. I did some searching, this build calls for a 500k pot, not 100k. It didn't change the sound too much, but it was a bit more saturated.

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  12. Just finished this one. On a roll this weekend. It is a very clean sharp fuzz and quite loud. Goes really well with my box of hall reverb heavenwithin mod pedal.

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  13. Agree with the brittleness of this one. Little harsh. Gonna swap some transistors around and see what I get. Any suggestions?

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  15. Hi, new to pedal building and decided to take a stab at this particular circuit. Didn't have some of the same values but the circuit works although with considerably less fuzz. Maybe someone can shed some light on what could be causing the lack of fuzz. The parts I used were as follows:

    1k instead of 1.5k
    2N5088 for the transistors
    1N4001 for the diode

    Thanks!

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  16. MPSA13's are Darlington transistors with a hfe (current gain) of 5000+. 2N5088's only have a hfe of 300+. So I'm not surprised you've less gain than the original. Swap out Q1 with a darlington and you'll hear a dramatic improvement.

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  17. I see. Ordered some MPSA13 transistors. Thanks so much for the info!

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  18. Got this board all wired up except replaced the 220k resistor with a 500k pot and used a 2N2089 transistor for Q2. Getting some nice gain out of this thing but is there a way to get rid of the high pitched squeal I get when there is 0 resistance? It would be nice is the pot was usable at all levels. At any rate, there is a sweet spot when rolling off the potentiometer and I've found that I prefer the sound when doing the following:

    multimeter set at 2M and testing the pot between lugs 2 and 3 with a reading of .298 (I'm relatively new to all this so please excuse my ignorance).

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