Monday, 14 July 2014

Dunlop JBF-3 Joe Bonamassa Fuzz Face

Request, and as it was a quicky I thought I may as well get it out of the way.  A tweaked positive ground Fuzz Face using Russian germanium transistors.  Being positive ground as usual I would suggest trying it with a negative voltage inverter to supply the -9V and allow you to use a 0V ground and allow you to daisy chain with all the rest of your pedals.  Note the required pin orientation and arrange them accordingly.

Info about the original:
Following in the footsteps of Fuzz Face masters Eric Johnson, David Gilmour, and Jimi Hendrix—Joe Bonamassa relies on his Fuzz Face to deliver his trademark searing leads. Tested and developed over several world tours, the JBF3 Joe Bonamassa Signature Fuzz Face is voiced specifically for Joe’s humbucker-driven tone, adding sustain and thickness for a rich, creamy fuzz. This pedal’s hand-wired circuitry is built around matched NOS Russian military germanium transistors for their characteristic warmth and growl. The JBF3 also features classic Omeg pots, housed in a polished copper finish that will patina over time. “I wanted this Fuzz Face to be a pedal that would instantly transform your tone,” Joe says. “It drives you to a different place as a player. Kick on the inspiration box!” Production of the Joe Bonamassa Signature Fuzz Face is limited to a single batch each year.






43 comments:

  1. I have the voltages. Set bias of Q1 to 0.9V and Q2 to 6.6V

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  2. I like how they put 3k16 in series with the 10k trimmer to q2 collector. Puts the resistance at right about 8.2k without adjusting the trimmer from it's center

    Same with the 25k trimmer and 20k going to q1 collector. Resistance is just about 33k at the trimmers center

    Kindof a smart design for easy bias tweaking. I may build one of these just to audition transistors

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    1. I could only get a 20k trimmer instead of the 25k the bias for Q1 collector only gets down to 1.2V - this may be why Im left with a quite bottom heavy and no top fuzz - not sure? its nice with my guitar vol backed off. I also could only source a 3k series res for Q1, but the bias is achievable.

      Im going to try replacing my 20k trimmer with a 50k and see if I can get more resistance to bring the bias down - logical really

      great looking circuit though, especially with some big russian trannies in it.

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  3. interesting sound for a Fuzz face. with the lower gain transistors its nice, not so over the top. circuit definitely works as it should. do you know what gains they build these with? Nice home for some mid range PNP 's. One thing i did notice. When you lower the volume pot it gets quiet really quick. Is that normal.

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    1. Nice one, thanks for verifying matey. And yes the resistance drops aggressively with a log pot rotating CCW from full so that is to be expected I suppose. You could try a linear but then you won't get the same kind of gradual increase in volume when rotating clockwise from zero. So I suppose it's a case of choosing the option that is most useful for the way you use the pedal.

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  4. Another great layout IvIark! I am tempted.... really tempted!
    Those 2 trimmers will come in handy for sure!
    Thanks!

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  5. Thanks for the layout. I recently bought 2 sets of NOS transistors for this one (a medium and a low gain set). I haven't had the chance to build it yet.
    However, in the schematic i found, there is another cap parallel to the 100K resistor. Is this in the original?

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    1. There was no parallel cap in the schematics at FSB, although it may be one of those pedals that has been tweaked over the time it's been available. So it isn't as far as I know, but you could always give it a try and see what you think.

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  6. looks like there might have been one under the board, but was deleted from the design.

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  7. Glad this one has appeared at last :) Just knocked up a pcb design from your layout. Cant wait to build it in a few weeks.

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  8. I did a layout of this a few weeks ago with trimpots as the only bias resistors. 50k for Q1 and 20k for Q2. I used a GT308B (hfe 70) for Q2 and an AC128 (hfe44) for Q1. I have never even imagined using gains that low for a Fuzz Face but I have hundreds of GT308Bs and they are almost all at hfe 70 with 0 leakage. The MP39B is a very low gain transistor as well. The circuit sounds great. It's especially good in front of a dirty amp like a Vox AC-15 or a Marshall. I have just ordered an actual JB-FF so I'll be able to compare my circuit against something other than a Youtube video.

    So here's what I'm hoping someone here can tell me -
    Fuzz 2 goes to a 10r before the 22u. What's it for?

    Thanks for this priceless resource, Mark and Miro. My tone has improved immeasurably since finding it.

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    1. Silicon Fuzz Faces are prone to oscillation and that resistor adds a little separation between the cap and the emitter of Q2 when the Fuzz pot is fully clockwise. It may work fine without it, or if you get oscillation earlier in the Fuzz pot rotation you may need something slightly larger. But for anyone getting some oscillation, that is the part that I would look at altering. Remember that if you still get a little oscillation, boxing it will usually cure that so you may not need to alter anything. If you're not sure just socket it and change the value when boxed as necessary.

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    2. Alex, got any gt308b for sale?

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  9. I have some problems wiring this with a TB switch? Could this be added?

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    1. What problems are you having? You can wire it as per the offboard page, note that Volume 2 is the output as per the notes

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    2. Hey Mark, so I can just wire it like always with the offboard wiring? No issues with the PNP positive ground?

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    3. I also had the pinout of the MP39b incorrect, hard to find those somehow?

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    4. Now I get the right bias values. I was just wondering about the offboard wiring needing to be reversed somehow? Also on the forum they mentioned a new schematic for PNP positive wiring.

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    5. No there's no issue, it's wired as usual.

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    6. ^^ The bypass wiring always remains the same, it's the power and battery wiring that changes which is why there are two versions of those diagrams. Just remember that the supply polarity needs to be done as per this layout, and so negative to supply red wire, positive to ground black wire.

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    8. No, the layout is right and in keeping with the usual supply and ground colours used, so black wire goes to the positive side of the supply which is then daisy chained to all offboard grounds, and the red wire goes to negative side. So all this affects is which terminal of the DC adapter you're soldering to, which is the opposite to what you would usually do.

      You have to change your way of thinking and remember that this doesn't connect 9V to the chain's ground. Think about the supply in it's most simple form, if you were to connect this up to a battery as described above and put it in a chain with negative ground effects, ground would be set at 0V for all the effects in the chain. If you were then to use a multimeter to measure the voltage between the negative side of the battery powering this and ground, you'd measure -9V because ground has been referenced to 0V and the negative side of the supply is 9V lower than that.

      That's why it's no problem having negative and positive ground pedals in your chain, it just doesn't matter. The problems arise on the other side if you also try to share a supply which then DOES try to put 9V to ground and so creates a short which will make smoke come out of your power supply.

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    9. Yes, that makes sense. I need to read up on this subject some more. I'll give a new try.

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  10. Any suggestions for npn substitutes to turn this into a neg ground device? (Switching caps around of course).

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  11. American: 2N1306 (or 2N1307, 2N1308, etc)

    Russian: MP38A

    European: OC140

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  12. Hi m8!
    Thanx for a great site, just finished soldering this together after trying another Fuzz Face DIY project which got me really confused (especially the pos ground off course), and just couldn´t get it to work. Now I made the PCB exactly as you described, I then hooked it up with your offboard design, and switched places with the red (+) and black (-), but that didn´t work at all. Troubled shooted for a while and went back to a standard bypass (http://www.beavisaudio.com/techpages/StompboxWiring/) and as loong as I hook up the PCB with neg ground (standard I guess) I get the fuzz to work, but if I switch places with ground and pos it´s dead quite. Also running it on neg. ground gives some oscillation when running on max fuzz (which I guess is normal when running the circuits in neg. ground). Any thoughts on this would much appreciated.

    Cheers

    / Richard

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  13. Just wanted to post a recap on my project.
    Everything got sorted out when I finally mannaged to get right transistors, and figure out their polarity. Just as mentioned earlier the pos. earth was just to switch power source red to black and vice versa. Finally I got this baby rocking! Cheers all.

    / Richard

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  14. Any good sourcers for these transistors, other than bulk on eBay?
    Just need one of each

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  15. Hi, can someone tell me, is it normal that this pedal to sound silently with vol and fuzz turned all the way up when is turn on then when it is bypassed?

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  17. q2 is gt308V not gt308b , q2 c 4.5V Greetings from Russia!

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  18. I love this! I have it with a negative voltage inverter, and I can daisy chain it fine. A buffer before it makes a huge difference. I prefer it with one before it, it has much more hair that way.
    It sounds great in many bias settings, too. I may build it with bias knobs instead of trimpots, next.

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  19. Hi there this will be my first diy positiv ground pedal what is the differenc between a standart one, just invert ground and +9V ?

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    1. the only difference is that if you don't use an inverter you will NOT be able to daisy chain this pedal with other non-positive ground effects.

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  20. Having a tough time with this circuit. I built it on strip board with a voltage inverter on board. With no transistors in the socket I'm getting -9v on the collector of both Q1 and Q2 no matter where the trimmers are set. With transistors in the socket I'm getting about -.5v to .9v on the collector of Q1 and Q2 depending on where the trimmers are set. I used a 30k trim instead of a 25k trim, but everything else is the same as the layout. I'm gonna set this one aside for a little bit and come back with fresh eyes, but any help is appreciated.

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    1. Nevermind, I accidentally used a 330k instead of 330r.

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  21. built it and love it, i used 2 of my best matched AC128 and daisy chained it,
    sound just as great as in the YT vid
    and i went for a black model ;)

    http://s7.postimg.org/rrx2969gb/IMG_0494.jpg

    http://s22.postimg.org/erwm1892p/IMG_0475.jpg

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  22. template for JBF-3;
    http://s15.postimg.org/groimsjdn/bonamassa_yellow_black_3.png

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  23. Could the Tayda electronics fuzz face kit be used to do this build with a few changes in components? Or is there another ready made kit that I could just add the different resistors to? I live in Australia so try to limit the number of places I order stuff from in order to not get killed on the shipping.

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