Sunday, 19 July 2020

Mighty Nut - ENGL Powerball Pre Amp Emulator Lead Channel

Schematic and info HERE

I added the" Low Mode" as well hence the additional Mode switch.


And by request, a layout with a Klon buffer before the main circuit.







53 comments:

  1. Hi fuzzhead, where did you get the schem ?
    I found an old thread on FSB but no schem
    Thanks !

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    1. Hi! Further down in the FSB thread there are links to the schematic. It is EAGLE files though.

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    2. Ah ok thanks, I don't have eagle so I didn't bother

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    3. Just fired it up and it sounding awesome once you get the bias right and the right transistors. I'm out of legit J201's so I tried of bunch of others. With PF5102's it nailed it. There is some squeal though when treble pot is maxed but hoepully some trimmed wires and a enclosure will solve it.

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    4. Hey, man. What's your opinion on this vs the G4? Different enough to give it a shot? The G4 is the best high gain distortion pedal I've played.

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    5. Yeah, I definitely think it is worth a shot. They're both high gain distortions so it's not like night and day but I feel that this one is more saturated and bit more low end...totally different feel when you dig in. Works much better for downtuned chugging....but remember to use a buffer upfront otherwise you might end up in Squeal City.

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    6. https://i.imgur.com/qZ0y42a.jpg


      This one is gain central. Woo! It's a ripper. Pretty noisy too, my wires are long as hell I know. I used the 5x6 buffer from this page. http://2.bp.blogspot.com/-ciSdhLUOXw8/VDAax2GGD-I/AAAAAAAAIog/jDJcvEog3ls/s1600/Buffers.png

      It didn't do anything. lol Which buffer are you using?

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    7. Gain Central it is.

      I plan to build a proper buffer like Klon Buffer but for this I just used a bypassed Boss DS-1.

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    8. My friend just sent me a Boss Bass OD, it worked perfectly. Good call.

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    9. Great! Glad it worked out for you. Is a little demo in the pipeline?

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    10. Here you go, man. A little ENGL vs G4.
      https://www.youtube.com/watch?v=MsJtNwTYWyk

      The ENGL seems like it's got a bit of a fuzz in it, the G4 is super tight and boomy, you really feel the bottom end in your chest. The ENGL has more gain and a good sweep in the upper frequencies.

      I'm still G4 all the way, gotta love those big asses. ;)

      Best Distortion: G4
      Heaviest Fuzz: Megalith

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  2. The best way to deal with sqealing issues in my experience is to add a buffer before in the chain.
    Glad you verifies it, i'll probably give it a try in the next months. Is it really a gain monster ?

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    1. Thanks for the tip about the buffer! Yep,massive gain on tap, the High/Low switch is usable if you don't want insane amount of gain all the time.

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  3. Sounds great ;-)
    I have a bunch of SMD J201, I'll report back

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    1. Tried with a buffer upfront and the noise floor is greatly reduced, could even tweak the trimmers for even more gain. Will definitely house this a small buffer daughterboard in front of the circuit.

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  4. Good to hear, but it's better to keep to buffer in a separate unit. I use a Klon buffer in a 1590a enclosure at the input of my pedalboard and it works great

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    1. Ah, good idea, I think I will go on that route then. Time to draw some buffer layouts I guess.....

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  5. So I built it, it works fine except a pb with the gain pot, if I turn it full CW, the gain drops and the sound becomes a bit gated. Back to 8/10 the gain gets back to normal.
    I noticed that the biasing of Q2 varies with the gain. do you guys have the same thing ?

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    1. No, I'm not having this issue in mine build. Are you sure you have 470k and 1m resistors in parallel connecting to the gate of Q2?

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    2. Ok, I had a tiny solder bridge that I didn't see when I knifed the circuit.
      Now, what a HUGE distortion, it sounds awesome, so brutal ! (and squeals like a pig :D)
      For sure a keeper, thanks for the great layout !

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    3. Great! Glad you managed to get it working!
      Do you know other amp emulators that needs a layout that hasn't been done yet?

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    4. Right now no (at least one that sounds good), but i'll let you know if something pops up

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    5. Hi Fuzzhead, if you feel brave enough, you could try this big baby : http://milas.spb.ru/~kmg/files/projects/Engl530/fet/engl530nod2Sch.pdf
      https://www.freestompboxes.org/viewtopic.php?f=13&t=9044
      The sound sample at the end of the thread is great !

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    6. That thing sounds amazing! Would love to do a layout for it but it seems to run on 200v? I have the greatest respect for high voltage stuff....I'm afraid I have to pass on this, don't want anyone to get husrt or even worse die.

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    7. Ah yes you're right, I didn't pay enough attention I thought it was a 9v JFet conversion like the Mighty Nut ;-)

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  6. For what it's worth, I changed the values of the trimmers to have more precision in their settings (20k for Q1&2, 50k for Q3&4). Oddly enough, this greatly reduced the squealing.

    Talking about other preamps, you could maybe take a look on all the Baja's on FSB, the EVH could be a good start ;-)
    https://www.freestompboxes.org/viewforum.php?f=13

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    1. Good info on the trimmers! I think I'll try it out.

      BAJA EVH 5150: https://dirtboxlayouts.blogspot.com/2020/02/baja-evh-5150-overdrive.html

      A PITA layout to get right but lots of helpful people in the thread came with input so I think it is good to go.

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    2. Oh damn! I didn't know there was a 5150 layout. 😳

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  7. Here are pics of my build. Really the best high gain distortion i built and even played !
    https://i.goopics.net/Q08a0.jpg
    https://i.goopics.net/KPd53.jpg

    fuzzhead, do you think you could redo a layout with the addition of a Klon buffer at the input of the circuit (true bypass layout, not buffered) ?

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    1. wow, nice tight build!
      Sure, I can do another layout with the klon buffer up front. Just give me a couple of Days.

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    2. That's great, thanks, and take your time, no rush ;-)

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    3. Uploaded another layout with the Klon buffer. This one was quite tough to keep it in a reasonable small size...

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    4. Thank you, that's great !
      After a quick look, ground should be 1 row up.
      You added a 4.7µf and 560 ohms at the buffer output, is this some sort of liaison between the buffer and the main circuit ?
      Also 3 22pf should be 220pf as per the original layout.
      I'll give a closer look when I have time

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    5. Right, thanks for spotting these mistakes, it is now fixed.
      The electro and the resistor after the buffer is in every Klon buffer schem I could fing although the electro could be iether 1uF or 4,7uF.

      One thing that bugs me a bit is the 100k resistor that is connected between ground and 560ohm/electro cap junction. It ould affect the bias and the overall gain for Q1 since it is /almost) parallel 1M gate resistor at Q1.

      Which layout/schem dis your Klon Buffer based on?

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    6. Ah yes you're right, the electro and 560 didn't show on a schematic I was looking at on the web.
      The layout I use is the one from tagboard : https://tagboardeffects.blogspot.com/2011/04/klon-buffer.html

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    7. There are mistakes around Q3:
      On the buffered layout you have a 470k connected to the gate that don't show on the original layout.
      The top horizontal 220k should not be connected to SW1 (and 470p)

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    8. Yes, you're right about the 470k resistor, removed it. I also noticed that pin 1 and 3 of the switch was mixed up compared to the original layout. Also fixed.

      So that 220k resistor is now connected to pin 3....but that 470pF cap should be after it as well as a 470k resistor, both is connected to ground.

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    9. This comment has been removed by the author.

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    10. Right, everything looks good now, I'll let you once built, I hope the buffer on the same board will deal with squeal.
      On a side note, I built the Amptweaker Tight Metal, what a great circuit. As heavy and tight as the Powerball, and totally noise free

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    11. Cool! looking forward to hear how it turns out!
      Amptweaker Tight metal sounds very good indeed. Did you do it on PCB or vero?

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    12. I built it from Alex's great vero layout. A lot of standing components but he managed to keep it 125B friendly
      http://guitar-fx-layouts.42897.x6.nabble.com/AmpTweaker-Tight-Metal-td9212.html#a9719

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    13. Yep, planning to do Tight metal soonish, demos sounds great.

      Finished the board with onboard buffer.....and strangely enough it is almost as noisy as the board without the buffer. Frustrating to say at least but I have yet to try your mods with smaller trimpot values.

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    14. Damn, too bad ! The buffer really needs to be in a separate unit then.
      Actually the best way to go would be to replace trimmers with fixed resistors after mesuring the right values.
      The tight metal is definitaly a keeper. I built the trimmer version for the gate, it's a set and forget setting. You will be surprised how the pedal is silent (and sounds great)

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  8. Hi guys. I would like to see the scheamatic, but I can't open .sch file and I don't want to install other software on my pc. Can somebody upload a pdf or jpg file of the schematic, please?

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  9. Is it possible to replace the high/low toggle with a footswitch? How would I go about that? I assume assign the top lugs for one channel and the bottom for another? If I want an led to indicate channel 2 is active id need a 3pdt footswitch right??

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    1. You would need only 3 poles, wired just like the toggle switch, or 6 (dpdt) with the LED, on either side depending if you want it to light with the low or high mode.
      This being said, if i were to build another one I would forget the hi/low switch and wire it hi mode

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  10. Can someone tell me which trimmer corresponds to which jfet on the buffered version please? Sounds great apart from that squeal

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    1. Follow the power supply path after D1 and the 100 ohms resistor.
      The trimmer connects the J201 drain to the power supply

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    2. Looks like this to me.

      https://i.imgur.com/Z6aZYBJ.png

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