Saturday 31 December 2022

Thorpy Fx The Warthog.

 The last layout of 2022!

Thorpy Fx take on a Rat. An input MOSFET gain stage with a bias control, a fancy high end single op amp and LED hard clippers. Looks fun!

Schematic is avaiable HERE.



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29 comments:

  1. Ian31 December 2022 at 19:05

    Anyone know where to get the IC, don't fancy chancing my arm with Chinese ebay sellers

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    1. Orion Tonehunt31 December 2022 at 19:15

      You could always socket and try with a plain jane TL071(I doubt you'd notice much difference) - OPA604s appear to be in stock with Texas Instruments for a little over $3 but I don't know about order minimums. You can also find DIP converted AD825s for very reasonable prices on eBay and are very unlikely to get counterfeits and it is a great match spec wise

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    2. Ian31 December 2022 at 22:55

      Couldn't we throw the classic rat substitute op07 in there?

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    3. Orion Tonehunt31 December 2022 at 23:16

      Sure could. Honestly with 9v distortion circuits I'm pretty doubtful you'd hear much difference between op-amps, other than being less or more noisy.

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    4. fuzzhead1 January 2023 at 09:46

      You can use pretty much any single op amp without internal compensation cap like, LM308, LM301, OP07 etc. Heck, you can use LM741 or TL071 as well, just omit the 33pF cap.

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  2. Ian31 December 2022 at 22:56

    Thank you Anders! happy New year!

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  3. Ian3 January 2023 at 23:11

    I see on the schematic a couple of the caps are tantalum - I'm guessing this is just for mojo and it's not too important?

    Also is it right that both South sections of the 1n418 clipping diodes don't link to any other parts on the board?
    I was trying to figure it out from the schematic but this stuff is web of my pay grade and I go cross eyed 😳🤤

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    1. fuzzhead4 January 2023 at 07:04

      For the caps, it doesn't matter in yjis circuit. You can call it mojo:-)

      The diodes is connected to the Source of Q2 via the jumper at column 14.

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    2. Ian4 January 2023 at 08:12

      Thank you Anders I am looking forward to building this one

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  4. Ian19 January 2023 at 20:51

    I built this up tonight but something is not quite right.
    The calibre seems to massively affect the gain, with lots of wiper noise.
    When the calibre and gain are maxed it sounds glorious...

    I looked at the schematic but was a bit out of my depth

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    1. Echowreck19 January 2023 at 22:14

      The Calibre control is a bias control for the BS170, so the noise is normal. The Calibre control on the actual pedal behaves the same way.

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    2. Ian19 January 2023 at 22:24

      This comment has been removed by the author.

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    3. Ian19 January 2023 at 22:40

      So a bit of research into this and the other pedal with the same control confirms this.

      I'm yet to find a rat varient that's as good as a rat😂

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    4. Orion Tonehunt19 January 2023 at 22:41

      "Crackle OK" ;)

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    5. Orion Tonehunt19 January 2023 at 22:55

      The input stage is 100% a ZVEX SHO

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    6. Echowreck19 January 2023 at 22:57

      "I'm yet to find a rat varient that's as good as a rat" Have you tried the Rat Tail? This is one of my favorite rat clones I've built: https://dirtboxlayouts.blogspot.com/2021/05/fuzzrocious-rat-tail-v2.html

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    7. Tom20 January 2023 at 03:44

      I used a woodcutter for year when there were few choices. I never loved it. I do love the Rat Tail, and the !981 DRV and Anders' Dronestortion and most recently the Fuzzlord Drone Master (almost a stock Rat but sounds loads better to me). Ian, you like spankier drives I think maybe. You'd probably dig the 1981.

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    8. Ian20 January 2023 at 09:23

      Cheers tom, good call 👍👍

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    9. Ian20 January 2023 at 09:24

      Agree there, 1981 is a great pedal

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  5. Ian19 January 2023 at 21:42

    This comment has been removed by the author.

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  6. Ian20 January 2023 at 10:53

    Here it is! Tag it!

    https://youtu.be/Mgusa76QECs

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    1. fuzzhead20 January 2023 at 12:27

      Thanks Ian! Sounds great!
      I'll tag it ASAP. Which op amp did you end up with?

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    2. Ian20 January 2023 at 13:12

      Thank you Anders!!!

      I used plain old vanilla op07!

      It has actually grown on me now I understand it's a bit better!

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  7. Orion Tonehunt21 January 2023 at 08:12

    Thanks for all the layouts, Anders! I notice PedalPCB has the schematic for the Thorpy Fat General Compressor that looks quite nice... I know you're a very busy man, but is there any chance we might get a layout?

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    1. fuzzhead22 January 2023 at 07:55

      It is on the list. Did some attempts but failed short since it is quite a finicky circuit to transform to vero. But...it is on the list!

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    2. Orion Tonehunt22 January 2023 at 18:15

      Legend 🙏

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  8. Tom10 November 2023 at 02:57

    Sounds great with an OP07. Tried an LM308 and it started cutting out on me. It sounded cool as hell though. But I'll stick with the OP07. The mosfet boost gives it a nice punch, so you can balance punchy and hairy all over the gain range. Thanks!

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  9. Mr Pinball20 March 2024 at 00:11

    Started this ages ago, but forgot about it and got round to finishing it tonight. I used an OP07, but when I completely dime the gain starts gating and goes all spluttery, then cuts out. Any thoughts?

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    1. Tom20 March 2024 at 02:11

      I can't offer too much help other than to suggest that you try different OP07's if you have them. I had the same issue with the LM308 but not with the OP07 that I auditioned.

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