Wednesday, 19 May 2021

Dunwich Amplification DIY HM2 "2021 Edition"

 Another take by Dunwich Amplification on the mighty HM2 circuit. Just released as a DIY project at OSH Park it has some tweaks all along the circuit compared to the stock Boss schematic. It also has a built in active clean blend circuit and switches for both hard and soft clipping diodes.

Schematic and BOM can be downloaded at OSH Park


 

...and a layout with "Dope-Ass Lower-Tuned" values for the gyrator eq section requested (?) by MTK.

These values were calculated by Ryan from Heard Sound Circuits and makes things sound....more evil.

(Low: 62,48 Hz, Mid: 716,67 Hz, High: 1065,5 Hz)

 

 
 
Demo time with MTK!
 
 



 

 



23 comments:

  1. Man... I've been taking a break from pedals lately but this is tempting me real hard. lol

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    Replies
    1. hey man, long time, eh?
      If you want me to push you over the edge I can upload another version of this layout with the eq gyrators especially tuned for C tuning? :-)

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    2. Damn you! Set it up. ha!

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    3. ... it starts.

      https://i.imgur.com/nLTzZCG.jpg

      Hopefully I'll get this done soon. I've got too many things and not enough time. lol

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    4. Duuuuude! This is killer. I've never played an HM2 before, it lives up to the hype. Chainsaw is such a perfect name for this one, you'll definitely need a buffer up front. I'm using a Klon buffer in the video, I switch it on/off a couple times at the end of the clip to show the squeals. The EQ is FAT, lots of low end, great sweep on the mids and highs. Blend, clipper toggles and gain all work as they should. It's got some really great tones, when it's not in Chainsaw mode, and covers a lot of ground thanks to the clipping toggles, it's not a 1 trick pedal. Great work on this layout, man. You're a legend.

      All right, I'm going back in to the no circuits time out. Thanks, man.


      Build - https://imgur.com/a/izvq3sg

      Demo - https://youtu.be/QBSSWg4OKb8

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    5. Yessss, he is back!
      A million thanks for verifying this! And the demo sounds awesome!

      So what's next?;-)

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    6. Yeah sounds really good even into a totally clean amp. I'm going to try this one even though I made the 4 band one as the clean mix, and slightly different EQ frequencies should make it worth it.

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    7. MTK..
      Which layout have you used??
      I only ask because in the pictures you posted there is a cap in the top right corner
      That you have is diagonal and the layout here doesn’t have any caps on an angle??
      Cheers

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    8. He used two caps in prallel to get close to 120nF (22nF+100nF).
      120nF isn't the most common film cap value.
      Other than that, as far as I can see his build matches the layout.

      Delete
  2. Awesome thanks for clearing that up..
    Just didn’t want to start building if the layout had been changed..

    You do such an awesome job with this site mate.
    Cannot thank you enough for the effort you put into it..
    Greatly appreciated as I’m sure others would agree as well.

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  3. Damn wish i was smart enough to be able to calculate EQ for different tunings - iam usually on C# standard but Will try build this one today - Husqvarna chainsaw!

    Cheers!

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  4. Built the C version with some small component changes to make it more "fuzzy".
    Damn it ended up great! Thanks alot for posting.

    https://ibb.co/r2VnFGb

    Went for the noisy TL082 paired with TL072, j201 as jfet and mainly D18 ( germanium glass diode that sounds really good, cant say it sounds germanium ).

    And some minor stuff, thanks alot for EQ shaping! And have a great midsummer!

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  5. Hi! What Ge diodes can be used? I have access to OA1160, OA1182, OA1180 and AA113, besides these I only have a salvaged Polish pair from a radio.

    ReplyDelete
    Replies
    1. I think you can use any of the diodes you have listed. The diodes is used to achieve cross over distortion,

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  6. Almost done with this build..(pcb oshpark version). Switches are always my headache ..Im a little confused about the switches... Spst on/on? Or on/off its what i need ?

    Thanks in advance and thanks for the great layouts

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    Replies
    1. SPST is always on/off. You can use SPDT on/On as well since one one of the lugs is unsused.

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    2. amazing thanks!! this thing rips!! preetty much the same with the OG HM2 japanese i have around.... just with more Bass available

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  9. how to find the schems of the dunwich pedals on osh park? the link doesn't work... thank you

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    Replies
    1. Most of Dunwich OSH PARK project is at God City at the nowadays.
      https://www.godcityinstruments.com/collections/diy-pcbs

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  10. Oof this is nasty! Squeals like a stuck pig without a buffer. After putting a buffer up front it's now quiet as a church mouse.

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