Thursday 21 March 2013

Boss BD2 Blues Driver

Requested by loads of people. I originally thought this would be a job for PCB, but after several more requests I had a think about it and estimated this may just about fit is a 1590B if I was careful.  It turns out it will fit more comfortably than I expected.  It will probably still need to be mounted with components facing down, especially with the dual log pot, but it'll still be fairly comfortable IMO.

Info from Boss about their original:

The BD-2 Blues Driver delivers the creamy, yet crunchy sound associated with great blues guitar. This popular pedal provides instant access to the kind of warm overdrive and emotive distortion usually reserved for 30-year-old tube amps.

    Classic "blues" guitar tones with tube amp simulation
    Warm distortion and overdrive
    Responds to nuance and volume changes 







100 comments:

  1. You guys totally rock. This one should be fun. Hey, any chance you could do a tutorial on this, explaining how to mod the curcuit. Kind of like how a Keely or Allums might. So us noobs can experiment with some knowledge. Thanks for all your work.

    Where's Geiri's build & demo? Is he sleeping?

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  2. Good God! Maybe I should start scanning the classifieds after all!

    Your ambitions are admirable. Bravo.

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  3. The diagram with Keeley mod for this would be great...

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    1. Sounds awesome even without the Keeley mods.

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  4. I have built about 40 distortion pedals of all sorts over the last 3 years. None of them sounds like the BD-2. It's a wonderful sounding pedal which compliments other pedals driving it.

    The combinations of the BD-2 with screamer/rat/FF/TB all deliver fantastic Rock tones.

    Thank you so much for this one.

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  5. Awesome! Definitely on my build list!

    A cheeky question: Is there any chance that you'll consider doing an HM-2 layout? I'm sure that it has been requested a couple of times...

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    1. Seriously, I would love to see an HM-2 layout. Make it happen!

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  6. from the FreeStompBoxes.org:

    "Boss BD-2 Blues Driver Mods - Robert Keeley

    This is not all-inclusive in what can be done to the Blues Driver. It is meant to give an idea of where the tone can be improved or changed. All of the changes are subtle but when packaged together offer a nice improvement.

    D3 Change this 1SS133 to a different (1N4002) diode for asymmetrical clipping. This adds second order harmonics. This adds to the tube type sound. I like the sound of this change.

    D7 D8 D9 and D10 Change 2 of of these diodes from 1SS133 to a single 1N4002. More second order harmonic distortion. Although the change is slight, I like it. We actually take out one of the two pairs and replace it with a single 1N4001.

    C1, C7, C6, C12, C13, and C15 Change this electrolytic capacitor to a 10uF Non-polarized caps. Non-polarized caps sound better . I like these anywhere there is signal coupling at this high a value.

    C14 Increase input coupling capacitor value to 0.1uF for increased bass response from your guitar.

    C100 Here is where we can affect the tone control. I prefer a little more lower-midrange and bass frequencies through the tone section. You can increase the lower frequencies by increasing the capacitor value to 0.033uF. Install a switch to add a 0.068uF cap in parallel with this value for the Phat Mode!

    Most of the ceramic caps are changed to Expensive Silver Mica (available through Small Bear Electronics http://www.smallbearelec.com or http://www.mouser.com or http://www.digiley.com). This is what makes our mod sound so good. A noticeable reduction in noise. An increase in the smoothness and no harshness left. This type of upgrade is not found in anyone's mods. The best sound is right here."

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    1. also refer to the wampler diy books (availabe on fsb)for various mods well described and simplified even for non-technical hobbyists. The mods are what makes this and ds-1 so special.

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    2. C100? WHere is C100 on this?

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    3. Not sure if anyone ever answered this, but looking at the schematic, it looks like this is the 18n on the bottom left going to tone 2.

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  7. Hey all thanks for the great information.

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  8. Is this true bypass or can I use a spst switch to turn on off? I know the bd2 is not a true bypass pedal.

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    1. True bypass. All the buffer switching components have been removed.

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    2. oh okay, doesn't removing those components change some of the sound characteristics of the pedal though?

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    3. Yes. The bypassed signal won't eat up your highs no more. Effect on characteristics? No.
      +m

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    4. It removes the input and output buffer. It may change the characteristics slightly but whether that's an improvement or detrimental we will know when someone who has an original builds one. One thing is for sure, I would never include the Boss switching in any of my layouts, it would make the layouts twice as big (or more in some cases) and if I wanted something dead on I'd buy a BD2. One of the reasons for doing layouts for the cheaper pedals is to use true bypass instead of the stock switching and remove two extraneous buffers from the signal path. I'm definitely a fan of buffers but prefer to choose myself when and where to add them to the path.

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    5. Could you recommend your favorite buffer design and your preference on where to put it?

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  9. Verified!!! I can't tell you how glad I was that this fired up, I was convinced that it wasn't going to work and be a nightmare debug. Fortunately there was none of that and it sounds pretty damn close to the demo, although there's not quite as much gain, I only had a 220k dual gang, would using a 250k make the difference?

    Cracking layout by the way, especially given the complexity of the circuit, my compliments to the chef ;)

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    1. I think the extra 30k could make some difference. I had a BD-2 that I modified and I always felt that it had too much gain at the very end of the gain pot.

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    2. Haha! Great!

      I was beginning to wonder what happened to you as you were pretty quiet for a while. Seems like you're back on the saddle!

      I don't think there's that much difference between 220K and 250K pot in there...

      Another one down! Thanks man!
      +m

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    3. Didn't see Geiri's comment.. :) I think the pot value being off 30K could make slight difference, but pots have tolerances too... So that's why i'm convinced that it will work just fine. Maybe a little off from the original on the control..

      I was prepared for a long debugging evening with that Blue Box tonight too :) Fired up right away and sounds just amazing :)
      +m

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    4. Yes nice one mate, glad I didn't have to go over this one again! :o) And nearly 500 verified layouts now, Miro will have to get his landmark post ready that he promised on 400! :D

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    5. I've finished the secondment I've been on so I'm back at my old job, which unfortunately means shift work, so I've not had as much time to build. I had a day off today though so I thought I better spend it wisely. You and Mark seem to be motoring on with the layouts, I think there were 56 unverified at the start of the day! Thanks for the info Geiri, I think for the extra £1 I'll find a 250k dual gang, stick it in and see if it makes the difference.

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    6. I'm definitely going to have a go at the blue box, the octave only synth type sound is awesome. Oh and roll on 500 Mark, that really is a crazy number of layouts you two have done.

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    7. If you want to test it before you get the 250K pot, add the 30K in value on to the 22K resistor attached to Gain A 1, and the 33K resistor attached to Gain B 1, so swapping for 56K and 62K resistors should do the trick.

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    8. I need to start preparing an oration... 500 is a big number. And no. I didn't forget that i promised to write the 500 post :D
      +m

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    9. Thanks Mark, I'll give that a go.

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    10. Miro - SPEECH SPEECH SPEECH SPEECH!

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    11. Haha :) You have a few more to go before that :P
      +m

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  10. With this I think removing D1 to D4 from the board and having a clipping switch will also give you a few more attractive options for increasing or changing the character of the gain. Doing something like this:

    i76.photobucket.com/albums/j6/IvIark_2006/DIY/Clippingswitch.png

    with your favourite alternative at the other side from D1 to D4.

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    1. Or maybe just remove D1 and D2 on the right hand side, put those on one side of the switch and a single 1N4001 in the same orientation on the other. That would make is stock in one position, and Keeley mod in the other.

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    2. I did think about trying this when doing the build but thought I best try it stock first, there's definitely scope for improvement with the sound, great at low gain but a little fizzy when cranked. Although I did just change my strings for 9s so that could have something to do with it.

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  11. Can't wait to start this one...

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  12. Was ready to build this one.... when I had the chance to build an original used one for €40.....so will not build it :P

    Really a great sounding pedal.

    BR

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  13. Hi Guys...need a little help with this one. On the final smidge of the drive sweep I get a high pitched noise...checked all for bridges, components/wiring..all seem correct , even changed the pot, ...any idea how I can tame this little problem as everything else works as it should

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    1. I have this same issue, I realize this post is ancient, but it's worth a shot. Did you ever fix this?

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    2. same for me. circuit seem correct but there is hiss noise with gain pot manipulation. did you fix this ?
      and another question : what is the function of the zener in this circuit ?

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  14. PPPsssttt...anyone home ??

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  15. Could anyone advice how to remove the input\output buffers and switching on the Boss OD3?

    http://www.freeinfosociety.com/electronics/schematics/audio/pictures/bossod3.gif

    Thanks!

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    1. Like this: http://i76.photobucket.com/albums/j6/IvIark_2006/Layouts/Schematics/BossOD3.png~original

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    2. Thanks! I appreciate the help.

      I've also found this one which omits even more parts: http://img392.imageshack.us/img392/4491/od3subclonebl3.jpg

      I see he removed the tone control but there are a lot more parts missing, any idea what's going on there?

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    3. He's taken out the opamp filtering section completely so I'd say that probably shouldn't be called an OD3 at all, it's just based on the OD3 gain stages. Mine removes the input buffer and buffered bypass components.

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  16. Hi Mark, thanks for this one and actually for al your work with these projects. I finished it yesterday, and the sound is awesome (even if it has considerably less gain than the original). But... I have the same issue as reported by tomo6314 above: there is a constant sqealing noise. When I touch the lugs 2&3 (connected together) on the gain pot this noise disappears. Do you have an idea what this could be? I routinely go through the strips with an xacto knife, so I don't think it is a short between the strips. Didn't check for cold solder joints yet though. Anything else I could possibly look for? Thanks!

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  17. built this one yesterday. I did the Keeley mods to mine plus a couple of Brain Wampler's mods too. I also gave it more low end for use with a bass. I didn't have a 250K dual log so I used a 250 dual lin and its taper is fine (and might preferable) for the gain control.

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  18. when building this version, keep in mind that it's bassed off of gaussmarkov's schematic: (http://gaussmarkov.net/layouts/bd2/bd2-schem.png). his schemo has different transistors and opamp than the original as well as omitted the two stage input buffer and 9V to 8V converter( the pedal is actually supposed to run on 8 volts). IMO, J201's don't sound anywhere as good as BF245A's which are closer to the stock 2SK184GR's) and I 'm using an OP07 for the opamp. if you're getting oscillation at the max gain setting, then either experiment with lowering the 9V voltage (it'll get dirtier quicker but stop the oscillation)or replace the 15K mid scoop resistor with a 10-13K one, or both. i'm running mine on 8 volts with a 13K resistor and it sounds great with a ton of distortion. I also replaced two of the diodes ( D2 & D3 with a red 3mm led, and D1 with a jumper)

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    1. John,
      I already tried the OP07 and as much as I could judge from the oscillation noise it sounded a bit more loose at the bottom end and therefore more tube-like. Also tried an LM308 and the result was similar, so I guess both are good candidates. But I didn't experiment too much yet, as first I wanted to get the noise sorted out. I'll try your recommendations and will also see if I can get some BF245A's and try them instead of the J201's

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    2. Also another question: how would I lower the voltage to 8V? Would a polarity protection series diode help (or actually rather two for that matter)? Or should I opt for a voltage divider made of resistors? Thanks!

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    3. you could just use a 10K trim pot and adjust it to 8V. I just used a 180 ohm resistor on mine.

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    4. Did the mods, here are my findings: my two cents are for the TL071 and the J201's. I only could get BF245B's, those resulted considerably lower gain. Also lowering the voltage to 8V lowered the gain too much for my taste. So I ended up using 9V, TL071 and the J201's. With this I had to lower the original 15k resistor to 8.5k to avoid oscillation. Unfortunately quite some highs got lost too with this, but the last 1/4 of the tone pot's range is still usable. The OP07 would not be bad, but with losing the highs the bass gets too spongy for my taste with that. The circuit is still pretty much usable, but far less versatile than the original BD2. Since the BD2 is not an overly expensive pedal I might end up buying one (again) instead of this circuit.

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    5. And of course thanks a lot for your advices. Also I've learnt quite some things about FET transistors during the debugging phase.

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    6. Only just noticed this John, I was on holiday when you posted so it was hidden by the time I got back! I didn't know the original dropped the voltage to 8V, and yes I think that would make some difference to the amount of dirt out of it. Did you experiment with this and do you think it's worth just adding an 8V zener?

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    7. you could do it that way, but IMO, it's biggest problem isn't the voltage, it's the fizzy decay that the originals are known for. a stacked NE5534 is the best way to make it sound better.

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    8. But I'm aiming for the fizzy decay, I want it just like the original, then it's everyone elses job to tell us how they made it better :o)

      God knows where I'm going to fit that zener in though.

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  19. mine's completed and I think that it sounds great. it has TON of gain/distortion if I want it to but can also be run clean. i'll post a sound clip with my p bass with it tomorrow

    pics:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/BBD-2/BassBD2-01.jpg

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/BBD-2/BassBD2-02.jpg

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  20. BTW, this vero sounds so much like the original that it even has the slightly (and dreaded!) fizzy decay that so many users of BD2's complain about. the solution (and only solution!) to solving that isssue is to use a stacked NE5534 in place of the TL071. I just tried it mine and it sounds awesome.

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    1. As I see you used a 47n cap in place of the 18n cap in the original one for the tone stack. Did you do this becasue you use it with bass? Any other changes? I'm still looking for a solution to get back some of the highs... Thanks!

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  21. Hi Friends! I hope you all had a lovely holiday season! I know I sure did. I went ahead and built one of these bad boys and it sounds amazing! So, I did the next logical step and built another one. Everything went great and I tested it on my bread board with all the pots hooked up via terminal strips. Then I soldered the pots on and boxed it up. I went to test it, and my bypass wiring worked, and the LED lit up when switch was engaged but no audio...? At first I thought it might be my wiring so I went ahead and tested it all and then finally just redid it incase just to be double sure. Still nothing. So I took the circuit out and tested it on the breadboard with the pots still soldered and got nothing. I desoldered the pots and hooked them back up to the breadboard via the terminal strip. I could kinda hear like a super faint sound, that sounded like maybe it was the signal. I checked all solder joints, and I replaced each major component (each one socketed) which was the chip, the diodes and all the trannies. My questions is could it be a bad dual gang pot, as that is the only pot that seems to affect the signal at all when testing on my breadboard. Or is it possible I burnt something out? I'm not really sure if there is any help anyone can offer me, I think I am more just venting frustratedly at this point ;)

    I figured I would shoot this plea out into the wonderful world of Guitar fx layouts and see if an angel out there could send me a sign or hint at what I am doing wrong. Or maybe even a trouble shooting technique I am not utilizing? The most frustrating part is that I built one and it sounds great, and also that at one point this circuit did work! Well I figure there is not much left for me to do so I may just give up and start over in regards to building the circuit. Onwards and upwards, amigos!!

    xoxox,
    Upthepunxxx! 2014

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    1. There's definitely a connection problem there, you can hear the noise as the connection makes and breaks. It could be solder, it could be a dodgy pot, it could be rust or oxidation on one of the component leads where it is soldered, it could be a wire somewhere broken in the insulation or it could be a single bad joint. Unfortunately it's one of those things that is impossible to identify from a distance.

      Just measure all the transistor and IC pin voltages to see if anything else suggests itself

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  22. Can anyone identify the diodes to match up to the original schem? I understand that the labeling on this is different than that of the actual board; I'm really trying to mod this layout to Monte Allum's specs ( I already own an H2O + modded BD-2, just want to play around with it without burning the traces off my own board). This would be very helpful, and I'd appreciate it quite a bit.

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  23. Very cool vid, thanks for sharing

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  24. Thanks so much for this! I just got it built and have no sound at low gain/volume, and just oscillation at higher gains. I've checked for solder bridges, but still need to take an audio probe through the signal. Here are my voltages right now:

    Q1: G - 4.54 S - 5.86 D - 8.68
    Q2: G - 5.55 S - 5.86 D - 9.33
    Q3: E - 9.33 B - 5.86 C - 5.56
    Q4: G - 4.22 S - 5.46 D - 8.68
    Q5: G - 4.61 S - 5.46 D - 9.33
    Q6: E - 9.33 B - 8.68 C - 4.61
    Q7: E - 3.57 B - 3.99 C - 9.33

    IC Pins:
    1 - 0.15
    2 - 4.64
    3 - 4.43
    4 - 0.002
    5 - 0.15
    6 - 4.64
    7 - 9.33
    8 - Starts at 0 and slowly creeps up in mV

    Any thoughts or ideas would be appreciated!
    Thanks in advance,
    Jeff

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  25. Mark, I have a store bought BD2 and I opened it up to see if I could socket the TL071 and try an OPA2134PA. So I open it up, and there is no chip in it! Unless I am crazy.......which is possible....where is this TL071 coming from?

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    1. Hey bud - it does have an IC, but you will notice that it is a SIP format, not DIP. Which means it's like a long strip, not a little rectangle.

      Check out this pic http://duhvoodooman.com/miscimages/musical/BD2/BD2_apart_2.jpg

      It's the long black bit on the left.

      To put in different types of regular DIP ICs for the BD2, you'll need an adapter like this: http://cimarrontechnology.com/so8dip8tosiladapterpn060301.aspx

      There should be DIY solutions though, so Google that.

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    2. Oh, nice links! Thanks Charles!

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  26. Awesome sound on that one. I love it, thanks a lot for your work. I had to build it twice, I make a mistake on my first try that I was unable to find. So I decided to remake it from scratch. That worth the work. Thanks a lot.

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  27. I encountered oscillation from having the gain up 1/2+ with the layout as-is. I found running a buffer before the input cleared that up completely. Maybe the input buffer is recommended for this circuit? Just an observation.

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    1. This comment has been removed by the author.

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    2. yes I think you're right. as is this layout work bad

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    3. I have made the entry buffer and no problem at all.

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  28. I've nearly finished this but have run into a slight problem... I don't know which way the IC goes, can anyone help please?

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    1. look closely at the diagram. there's a small light gray 1.2 moon at the top of the IC.

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    2. Thanks heaps John, I didn't spot that. This is my first pedal build so I'm just learning. Found this helped too: http://www.ti.com/lit/ds/symlink/tl071.pdf

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  29. Ive built two of these and would like to try and decifer the keeley mod. Can anyone help with this? Has there been a layout with the keeley mod added?

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  30. How essential is the 8.2v zener for this? I have plenty of 9v zeners...

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  31. Ok, so I used an 8.2v zener, put the thing together, got no sound, but a bloody too hot to the touch 8.2v zener. I've checked all the cuts and cleared the tracks with a knife and a run through with the soldering iron. Any ideas where to go with this now?

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    1. Did you get your problem fixed? I've having same problem, and I can't figure out what I'm doing wrong. Zener diode is running hot and I have no sound

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    2. Nope. It's in the parts bin currently.

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    3. Is that zener a part of some mod? Since this layout doesn't have one.
      I assume the zener you're talking about is connected either in purpose or in error to the supply voltage (9V). With signal levels no diode shouldn't heat up, the current is so low. But if there's a low wattage zener as a overvoltage protector or polarity protection it can heat up.

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    4. Ok, my bad and blindness :D Didn't see the supply voltage discussion there even though I tried to browse the origin for the zener...
      But yeah, there's something else going on like Mark states below.

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  32. Check the voltages of the IC pins and all the transistor pins and post what you get. In fact check the voltage at both sides of the zener while you're at it just to see what you're getting there.

    Those voltages will give us a big clue where the problem is.

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  33. Noob question, but w/c is the Gain A and Gain B for the dual gang? Is "A" the upper lugs and "B" the lower ones?

    Thanks

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    1. The lower and upper lug rows are the functionally identical. Both "rows" just have their own resistor tracks and wiper.

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  34. This build has 1/4w resistors I assume.. Does that change the sound because the BlueDriver actually uses 1/8w resistor which I know your aware.. Im just looking to see if the 1/4w resistors change the sound at all..

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  35. Hi there,

    I built two versions of this, the original with the dual gang pot, and a modded version using two independent pots replacing the dual gang. I also added a couple of switches to mess around with different diodes and there is a problem with noise on both pedals.

    The original emits a whine when the volume or gain are turned up too high and the volume is a little lower than what I expected overall.

    The modded version emits a different noise that is dependent on the two gains and the volume.

    If anyone could point me in the right direction as to what may have gone wrong that would be fantastic!

    Thanks very much for ALL the layouts, it is all brilliant work!

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    1. Hey man. I just built a couple of these and I think I ran into the same problems as you. The high pitch whine for me was fixed by lowering the resistor value of the 15k resistor in the top left corner of the build. 6.8k worked for me but as you go lower you lose more treble. I was able to bring back the high end by replacing the left-most 18nf capacitor on the build with a lower value cap. I settled on 4.7n but I socketed a bunch to find the sweet spot. Try out some different values in those two spots and see if it helps you. Good luck.

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  36. Hey, can you guys help me, im building a boss bd2, but i replace the dual 250k pot with two single 250k pot. When i engage all two pot together all the way up, i get some high pitch noise that annoy me...
    Maybe there is some solution for my problem, thanks

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    1. I've built this years ago and I left it on the shelf because of that same problem. I used a 250kA dual pot, but those individual pots shouldn't be the problem here.
      I haven't tried to fix this, but you could try adding a 50k trimmer in place of the 22k resistor going to Gain A 1 AND another 50k trimmer in place of the 33k resistor going to Gain B 1. Set the trimmers to those values (22k / 33k) and engage the pedal, Once the squealing starts, turn the trimmers up (more resistance that is) and see if you can tame the squealing. It might be enough to adjust just one of the trimmers, but that has to be tried. Don't worry, tweaking with those resistors won't break the pedal, it just alters how the gain pot works.
      If you get the gain to work properly, just leave the trimmers there or remove the trimmers and measure what the adjusted resistance was for each and replace those removed resistors with new ones with those values. Most likely the measured values are going to be "non standard" (say ie. 44k) and you have to use the closest standard, rounding up (say ie. 47k).
      All this is based on similar problems with other, quite a bit different overdrive circuits and thusly it may be the idea above might not work at all. But it should be easy enough to try :)

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    2. Update on my idea...
      Now that I browsed the comments above, this seems to be a problem with other builders also. There might be something behind the supply voltage adjustment. In the original unit, the supply voltage is lowered to 8V. This can be done with a resistive divider or as talked above, a 8V zener from supply (9V) to GND. I would go with the divider, but I'm not sure if it's the preferable way to go :)

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  37. Fun fact.... if you make a rookie mistake and forget to put in the electrolytic caps, the circuit still fires up.. but it is VERY distorted and VERY quiet.

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  38. working on matching up the components with the original schematic ref numbers so y'all can do the keely mods etc, fingers crossed i get them right

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  39. Does anyone have a list of voltages for a working unit - Mine's doing what it should, but isn't getting anywhere near unity volume, even at full tilt.

    I've subbed the dual 250 pot for a dual 100k, just as I prefer the low gain sounds of this pedal, but that's only a recent thing; I had it working for a while, then the volume just dropped mid play and hasn't gone back up again.

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    1. Update, I measured my transistor and had more than 0.5v difference between the E and B pins of Q6 so investigated, replaced the transistor and now it's great!

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  40. What schematic this veroboard is based on?

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    1. From memory I think it was this one:
      https://ibb.co/gPD8CTR

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  42. Thanks lvlark and everybody else who has commented.
    I've just built this and am delighted with the sound. I used J113s, a TL071 and a 220K gain pot.
    A few ideas for anybody considering building this.

    First, in the layout, the 8.2V zener seems to be connected between 9V and ground. Without some resistance before the zener, won't this just drag down the whole power supply creating a kind of 0.8V short-circuit? A series resistor establishes a voltage divider with the load resistance. If the load is pulling lots of current because the gain is high, then the load resistance is low and the zener will not have to do anything because the voltage across it will be less than 8.2V. It's just Ohms law. I have no idea what current the circuit draws. I gave it 80mA, which implies a series resistance of about 16 Ohms (with my PS, which is 9.5V, unloaded). So, the circuit will get 80mA and then the power rail will start to sag, which will, I suppose, result in more clipping. ... Anyway, if the zener is getting hot, the lack of a series resistor may be part of the reason. If you do use a series resistor, watch the power rating; it probably needs to be at least 0.25W.

    Second. My circuit has squeal / oscillation if it is connected directly to my guitar. Convergent Sound (see above, 17 July 2016) suggested that the input needs to be buffered. That would seem to be the case, at least with my build. For my purposes, the solution is simply to put the BD2 after another pedal (which is where I would put it anyway). Almost all pedals are going to buffer their output. This completely resolved the squeal issue.

    Third. I couldn't easily get the non-standard capacitor values 18n and 56n. I used 33nF for the left-most 18nF, and 22nF for the right-most 18nF. I put 47 nF for C18 (in the BD Light circuit diagram) and a 47 nF plus a 10 nF in parallel for C17 (in the BD Light circuit diagram). I don't know if this matters much.

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