Wednesday, 10 July 2013

NPN Si Tonebender MKII

This one's for those who had trouble with the Ge layouts. It adds Orman's and Tremblay's mods to the classic and it is supposed to sound like the real thing. If you want, you could swap the 5K6 resistor for 10 trimmer or even take it off board to act as a bias control. Transistors are supposed to be very low hFE Si devices, so you should be golden with 2N2369 or 2N3903.

Already verified by Rudeez. He also suggests that 2K lin pot for attack will work a lot better than 1K.


45 comments:

  1. Interesting, I'll give it a try thanks Miro
    (Should be Volume 3 on the layout)

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    1. Yes it should. Damn i'm off...

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    2. Label fixed with help from rudeez...
      +m

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  2. Finished mine before the the layout was posted as Miro said.
    Recorded a demo of it to, will upload it on youtube next week.
    Modded mine further for even more gated sounds, 5K pot for attack, sticked with 10K for external Bias but also tried 20K which resulted in more noise.
    I strongly recommed a trimmer instead of the 5.6K resistor and maybe even have it external as it do change the sound alot.
    After some testing i went on and used 2N2369 (60hfe) for Q1, 2N2222A (160hfe) for Q2 and finally BC109B (130hfe) for Q3, although it all comes down to taste so try different combos and measure the trannies.
    A pic of it will do for now! http://instagram.com/p/bo_2DixWEj/

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    1. That looks fantastic! If I wanted to use a 10k pot to make the bias external, which pot lugs would i connect to the board?

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    2. Beautiful work as always Rudeez!
      +m

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    3. hitokirimnb: you would want to take that 5.6K to the right out and take wired from the far right on those rails and plug the lower column to lug 2 and upper one to lug 3. put a 10K linear there. 20k just resulted in more noise and pretty much the same results.

      miro: thanks! but i also want to thank you as well for helping me with the layout for this after building 3 boards of regular tonebenders haha!

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  3. How would this compare to the Hot Silicon Fuzz?
    I may have to build this and find out for myself LOL

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    1. Well, did you get to build both? any after thoughts?

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  4. I'm new to this so bear with me. It says volume 2 to output. Does that mean I solder volume's 2nd lead (middle one) to the 3PDT switch's 7th lug? The input (green wire) goes to the input jack's tip right? Does the black ground wire go to input jack's sleeve? Do you omit the output jack's sleeve or do you connect that to ground too (input jack's sleeve)?

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    1. You don't want to connect the board directly to either input or output. If you do that you can't have "true bypass". Both in and out shout be routed through the 3PDT switch. Take a look at the Offboard section above. The offboard wiring guide shows an excellent way to connect your board's in, out and ground to the jacks and switch.

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    3. Thanks for the answer Alex. The offboard wiring shows an input and an output wire going from the circuit to the switch. This circuit (NPN Si Tonebender) as well as others don't have an output marker so I don't know what to connect the 7th lug (where the output of the board usually goes to) to. Also the offboard wiring doesn't have a place for an adapter so I don't know how to include that.

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    4. So ultimately I just need to know where's the output of the circuit. I'm sorry if what I'm asking has an obvious answer.

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    5. It says on the layout notes - Volume 2 to output. So volume pot's lug 2 is the output of the circuit.
      +m

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    6. Wow it's all starting to make sense... thanks a lot!


      Which transistors should I use from this list? These are the only ones available to me : http://www.mammothelectronics.com/category-s/105.htm

      Also which diode should I use from this list? These are also the only ones available :
      http://www.mammothelectronics.com/category-s/79.htm

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    7. You could try 2N4401 or 2N3904. For a diode you could use 1N4001 or 1N4002.
      +m

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    8. Again, I'm sort of new to this, but how would I be able to know which diode/transistor can replace another diode/transistor? Is it the gain level of the transistor and the volts of a diode? How do you measure the hfe of a transistor?

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  5. I've been terrible lately at posting my builds and read through comments here, anyway. Here's my build of this one, trannies used described earlier:
    http://instagram.com/p/bo_2DixWEj/

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  6. Built it, with the attack a 5k pot modded to about 2.5k and the last bias resistor adjustable with a 10k pot.
    Snarly and spitty to pretty smooth with BC108s with an hFe from 60 to 120. Have to dial them in, and try a bit higher.
    The attack cuts off sound at just shy of minimum and it adjustable to have a gate similar to a Devi Ever pedal when you tweak the bias. Weird!

    Checked it against the Hot Silicon fuzz that is on my board, and the HS is far smoother and more compressed but similar enough to bear a resemblance.

    Cool circuit. When I dial in the transistors it will be great.


    NOTE: Battery is silent but on wall wart power it tends to squeal but the Hot Silicon doesn't.
    Anyone have an idea how to tame this? Bigger power filter than 47uf?

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  7. 47uf should be enough for filtering, I've built this and it works fine with a power supply. You should check for a solder bridge somewhere.

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    1. I find this sounds a lot like a tonebender whereas the hot silicon isn't. The hot silicon is a good fuzz but I find it doesn't have the splattiness.

      I used 2n2369 transistors, q1:70, q2:70, q3:100.

      it sounds very close to my germanium tonebender build.

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    2. Thanks guys. I'll check again, and adjust the gains. I have 68/100/128 in there right now.

      This would probably be fun with a switch for a bigger input cap, too.

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    3. I also went as far to put a 100k pot for the collector on Q2 external and a external 10k pot for the collector of Q3. It allows me so many different possibilities with it. I love it. It's one of the best sounding fuzzes I have. I definitely recommend this to anyone who wants a tonebender 2, but, without the hassle of biasing problems and temperature issues.

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  8. Replies
    1. Yes it is. If you want to leave it out, just put +9v on the top row.

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  9. Also, there seems to be a compression issue with the build. Is there something I'm missing? Maybe a cap value that's possibly too large or otherwise?

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  10. Actually it's more of a gating issue. When I hit a chord, it sounds as if the volume goes down slightly.

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  11. You could try biasing Q2 and Q3. Q2 controls the gating. Whereas Q3 changes the compression and fartiness. You should be getting voltages between 7 to 9v on the collector of Q3 in order for it to sound good. Pull out the 5.6k resistor and put in a 10k pot on the collector of Q3 and dial it in by ear. You'll be surprised how good this works. :)

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  12. Hi just built this and it was my first vero project. At first it was sounding gated thin and broken so the next morning I swapped trannies for some I just had I think 2n2904? Anyway it sounds great now I must have had a tiny solder link that I fixed swapping them. Thanks for your work ill def be trying more of your layouts

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  13. Now here's another one that sounds astonishingly good on bass. I used 2N3903s (which rule), hFEs of 80,90,110, and a 2K attack pot. I boxed this up with a Split N' Blend, and I call it the "Blender Bender". One benefit to having the 2K attack pot, is that with the volume cranked and the attack all the way down, you can actually get some really good RAT-esque tones.
    I had a Big Muff ready to box, but as soon as I built this, I forgot all about the Muff. A real winner.

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  14. Late to the party but built one last night and had a bit of a "where has this been all my life?!" moment. Brilliant fuzz! Can't wait to be back home to try it at decent volumes now, was gone midnight when I finished it off and had to be far too quiet... I replaced the 5k6 with a 10k trim and can see why many would want it as an external pot.

    Will probably get some low gain trannies in to try some swapping, lower triplet I had in ranged 120-220 in HFE.

    Now to get that hammerite MilkIt wedge enclosure drilled...!

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  15. Hoping someone can provide a small bit of clarification on the external bias pot for Q3.

    According to Rudeez, I should connect the "lower column to lug 2 and upper one to lug 3" but does Lug 1 then connect to ground (seems to make the most sense but I just want to make sure)?

    Thanks!

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    2. OK...so I went ahead and built the circuit (used sockets for my transistors) and ran into a snag.

      Using my assumption that "lug 1" of the Q3 bias pot went to ground (I replaced the 5.6k resistor with a 10k pot), the pedal fired up but had zero volume (even with full Volume and Attack) unless I maxed out the Q3 bias and even then it was incredibly quiet.

      After poking around with my multi-meter and thinking about things a little more, it dawned on me that "lug 1" should probably be "unconnected" or MAYBE soldered to "lug 2". This arrangement gave me the same low volume but it remained relatively level regardless of the Q3 bias setting (note that Volume, Attack, and Bias work as expected, I just have VERY little overall volume).

      I traced the voltage through the circuit as best as I could and here is what I found:

      (9 volt battery measuring ~8.5 V at input to board)

      8.37V measured at 47uF cap
      8.37V measured at "top rail" of 10k resistor
      6.44V measured at "bottom rail" of 10k resistor

      WITH BIAS SET TO FULL:

      Q1 C = 6.44 V
      Q1 B = 1.06 V
      Q1 E = 0.49 V

      Q2 C = 1.22 V
      Q2 B = 0.58 V
      Q2 E = 0.02 V

      Q3 C = 8.20 V
      Q3 B = 1.21 V
      Q3 E = 0.66 V

      8.20 V at lug 2 and 3 of the Bias pot
      8.20 V at "bottom rail" of 100nF capacitor
      ~0 V at "top rail" of 100nF capacitor

      WITH BIAS SET TO 0

      Q1 C = 6.44 V
      Q1 B = 1.06 V
      Q1 E = 0.49 V

      Q2 C = 1.22 V
      Q2 B = 0.58 V
      Q2 E = 0.02 V

      Q3 C = 7.06 V
      Q3 B = 1.21 V
      Q3 E = 0.66 V

      7.06 V at lug 2 and 3 of the Bias pot
      7.06 V at "bottom rail" of 100nF capacitor
      ~0 V at "top rail" of 100nF capacitor

      Does it make sense for me to suspect something odd is going on with the 100nF capacitor or should I also be suspicious of the low voltage at the Q2 collector?

      As always, any advice would be MUCH appreciated. I feel this one is SO CLOSE...

      - brad -

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    3. ...yet another update...

      Yesterday I took a MUCH closer look at my Vero board and saw a few dodgy spots where I either had too much solder and risked bridging or not enough solder and risked a poor connection. I took a couple minutes to flow the solder a little better in these areas and...sure enough...the project ROARED to life!

      After playing a little, I started to audition transistors and wound up going with three 2N3903's...Q1 at 68, Q2 at 80 and Q3 at 84. This combination seemed to give me my favourite raucous tone with full Attack and just the right amount of hair at minimum Attack.

      One minor complaint I have is that the linear 5k pot I used for Attack seems relatively subtle in its adjustment right up until the last 1/4 turn at which point I get a very dramatic jump in fuzz. I could understand this a little more if it was a logarithmic pot, but shouldn't it be smoother with a linear pot? Is this because of the mod from 1k to 5k or could this be a sign of some issue with the pot or my circuit?

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    4. Yeah I just built one of these, and tried four different types of transistors in it, the MPSA06's are winning currently while I wait for the 2n2369's to come. My attack pot is currently a 5k too, and I get all kinds of gain out of the last little bit too. I'm ordering a 2k. I put pots on all the control resistor positions, but they aren't that useful. Putting a 10k pot at the 5.6k position is the only one I like. The others can induce some self oscillating stuff, but I have a few fuzzes that do that already.
      I also put a 47n and a 10n on a dpdt switch for a Fat mode.. it sounds pretty awesome. Great build

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  16. OK so I thought it sounded good with MPSA06'S. . Wrong! It sounds amazing with the 2n2369s. Love this

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  17. OK so I thought it sounded good with MPSA06'S. . Wrong! It sounds amazing with the 2n2369s. Love this

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  18. Hello, I'd like to use the trim pot instead of the 5.6 but I can't figure out how to put it in with this layout. This is my first vero build. Any advice?

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    1. hi and good luck!
      you should omit the 5,6K and the link at the left. lug1 of the trimmer must go next to the collector of Q3 where the leg of 5,6K is now on the layout.to the upper strip where the link you've omitted and the down leg of the 100nf are connected, you must solder the lug2 of the trimmer. leave lug3 of the trim unsoldered or cut it off to prevent any shorts.
      hope i helped!

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  20. 2k attack pot is a big improvement

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