Sunday, 12 July 2020

Earthquaker Devices Black Ash

From the source:

Limited to 1500 units worldwide, Black Ash is a fuzz/overdrive that takes some cues from the vintage “three-knob Bender.” It uses a highly curated cache of rare and irreplaceable components including paper-in-oil capacitors and NOS half-watt carbon composition resistors from EQD President Jamie Stillman’s personal stash to light a fire under this classic fuzz/drive with an explosive-yet-detailed treble response, a sturdy midrange, and subterranean bass extension.
  1. Fuzz: Adjusts the amount of gain. Counterclockwise for less fuzz, clockwise for more fuzz.
  2. Top: Adjusts high frequencies between 2kHz - 10kHz and controls how “forward” the guitar sits in the mix. Counterclockwise for less top, clockwise for more top.
  3. Level: Sets the output volume. Counterclockwise is quiet, clockwise is loud.

     It's essentially a modified silicon tonebender.





    Stock:




    External Bias:







43 comments:

  1. i bulit this . with the trimmer on the board . doesnt do much at all :-/ no sound

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    1. Mine is going now, there are some errors in this schematic. On Q3 and Q2 Base and Collector needs to be connected

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    2. Spot on. I must have deleted the link when I was moving stuff around. I’ll update the layout. Cheer for the verification with that change.

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  2. thanx :) (also it's 12x17 not 15 )

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  3. Which transistor would you recommend for this build?

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    1. Low gain Si transistors, so 2N2222 might be a good start.

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  4. Is the 1K from Q2 supposed to go to ground?

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    1. yes, i just corrected it. not sure how it was verified with that error. should be good to go now.

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  5. What range would you consider low for a Si NPN? If modding a multi Si NPN build by subbing in a Ge NPN would it be more effective nearest the input or the output (obviously adding a trimmer for it)?

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  6. Looking for help... I've completed the version with the trimmer and I've double checked everything against the lay out, triple checked my double check etc... Components are the correct values and oriented correctly, nothing is grounding out and I've got the pots connected per the layout.

    Volume is just over unity with the volume pot maxed, and the gain pot works in reverse; CCW max gain, CW no gain.

    Socketed 2N3904s...

    Any help would be appreciated.

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  7. Hey guys, just built this with the bias to pot in enclosure. I've used 3x 2n2222s and it's got a farty, mega gated tone that is barely audible. Any ideas what the tranny voltages should be for this bad boy?

    Any suggestions would be massively appreciated!

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    1. Ahh I’ve put a 22pf instead of 2.2n.... off to bed now but will check it tomorrow

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  8. Built the external trimmer version. Used 2N2222's. Farty distortion. Checked everything. Something is off here.

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    1. This comment has been removed by the author.

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    2. Did you check the transistor orientation? I first built mine based on the shapes outlined in the layout, but the pin out was backwards.

      I flipped mine around and got a little more volume and gain, but still need to crank the volume to get unity.

      I re-built using a different layout, so I know my parts are good... Good luck!

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  9. There are some differences from the layout and the schematic online.

    The 100uf + should come after the 1N5817.

    The 22K should connect to the other side of the 47K.

    The bias pot wiring - the 22k and 100nf should connect to both Bias2 and Bias3.

    Please correct me if i'm wrong. But i'm seeing discrepancies.

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    1. And im not sure what the upper drill hole under the 2.2nf is doing.

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  10. With the changes I listed above except I left Bias3 unconnected - the circuit works. Not sure why other's are claiming this is verified when there is still mistakes (atleast on the external bias version that I used). Easy changes though and the pedal sounds fantastic now!

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    1. Amazing, I’ll wait until the layout has been altered to make my corrections! Good spotting

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    2. Quick update - When I left out the Bias3 wire, then I then swapped Bias1 wire to Bias3 lug instead. This is more of a preference, but now turning the knob clockwise kinda gets louder and less compressed - which makes more sense to my ears.

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    3. cheers man. just took a look at both layouts again and made some quick corrections. bias 1 and 2 or 2 and 3 can be connected or not as it's just acting to control the voltage to the collector of Q3. layout has been updated.

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    4. Hey should the 100n cap top right be connected to the bias 1&2 strip? Can’t wait to make these changes later!! Thank you all for your keen eyes and regular updates!

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    5. Yes the 100n needs to move to the bias 1/2 strip. And the 22k at E9 needs to move to J7.

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    6. hold up. i checked the schematic again and spotted the problems. i reuploaded the layouts and remarked it unverified until there's confirmation the new layout is correct.

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  11. The new layout still isnt correct. the 47k needs to connect to Q2 Collector. And that 22k is still not on the right side of the 47K either.

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    1. good spot, i forgot to save the correct image. should be fine now.

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    2. Now that my friend, is a layout! Nice work - and as always - much appreciated!

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    3. Cheers man. Drives me nuts sometimes when it’s something stupid. Plus was able to make it a little more compact, which is nice.

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  12. Just made this with some old Fairchild BC208's and it sounds fabulous!!

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  13. Made this and it is absolutely killer! 2N1308 loaded ;D - Thanks again for the layout

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  14. The external bias layout works great and the circuit sounds a+ with 2N3903 transistors. Thanks again!

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    1. I spent a little time swapping transistors in and out of this today and landed on this (assuming Q1-Q3 go top to bottom in the layout...):

      Q1 - 2N3903 103hfe
      Q2 - OC140 85hfe
      Q3 - 2N3903 121hfe

      I tried the Ge NPN in all three spots but it seemed to make the most notable difference in Q2. Anything over about 120 in Q3 started to get a bit farty, and although values under 100 in Q1 sounded very nice (I tried a few different 2N3440 there with hfes in the 70s), I like the smoother/more saturated sound of the slightly higher HFE 2N3903.

      This is a really nice tone bender.

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  15. What pots are you using for this?

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  16. I created a stock layout.

    To be honest, I'm a beginner so I don't know if I made it exactly,
    but it became my favorite sound.

    thanks!

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  17. Transistors picture are not in the right direction.

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    1. The image of the transistors don’t matter, the pin out does. As I noted in the layout, use low gain Si transistors, which can vary in orientation, therefore the direction of the image for the transistors is inconsequential.

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  18. Just made this with 3 CV7112s that I’ve had waiting around for a while and it sounds pretty great. All three were right around 80hfe. Maybe try some Si a little higher tomorrow and see what that sounds like.

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  19. For anyone building up the 4-knob version, I'd suggest swapping out the bias pot for a B20K or B25K. As it is the control is very subtle and makes more sense as an internal trimmer to set a 'proper' bias and leave it. Changing the pot value lets you turn it into more of an effect and can get you into gated/zippery territory.

    I also swapped the 'bright' pot out for a B50K just to get a little more range out of it as well. I think you could even go to a B100K for a more pronounced LPF. Stock setting cuts off at around 2900Hz, 50K pot = 1450Hz, 100K = 725Hz.

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    1. Thanks for your suggestion - I ended up building the 4-knob with the B20K for bias and B50K as bright pot - very nice!

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  20. Built the 4 knob version with 2n4124 transistors. Sounds really good! Why is this still marked "unverified"?

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  21. Great layout, thank you very much!

    I built the one with external bias and used a 50k linear because its range depends on the transistors used and with some trannies there's not really much going on with a 10k pot.
    Also tried a 50k as tone pot but eventually settled on a 25k as I like the subtle sweep better.

    Transistors from top to bottom are Q3, Q2 and Q1 and experimenting with those can be quite thrilling. My favourites so far are russian MP38A for Q1 and Q3 and a 2N1302 for Q2.

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