Sunday 16 January 2022

ProCo / Fuzzdog 3-Band Rat

 This is a request. Fuzzdog tweaked a the classic Rat circuit a few years ago. It includes the "Reutz mod", a diode selector switch for assymetric silicon/LED clipping and a Marshall 3-band tonestack. The output buffer is tweaked into a gain recovery J FET stage to cover up the lossy tonestack. For a Sunn/Supergroup tonestack, just replace the 33k resistor with 56k and 470pF capacitor with 270pF.



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33 comments:

  1. Marcello M.16 January 2022 at 18:44

    Thanks, man. I was drawing it too. I will test this week and I come back to report.

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  2. Chris17 January 2022 at 19:50

    possible to use a J201? JFETs are like gold dust now in UK, can only buy J201 SMDs at the moment and have to solder them onto 3 pin adapters :-(

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    1. Chris17 January 2022 at 19:51

      actually is a 5458 better? Can still get those (and I'm sure I've used been in a rat clone before too)

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    2. kramerian17 January 2022 at 22:20

      J201 do fine in rat.

      even if you converted to npn, sound still in same teritory. The magic happen because slew rate opamp. I cant hear night day difference between 308 and OP07, but i can hear if use other single opamp.

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    3. Ian17 January 2022 at 23:27

      I got stung with fake j201's...it's such a shame.

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  3. Tom17 January 2022 at 20:48

    That’s whats typically in a stock rat actually.

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  4. Tom18 January 2022 at 02:19

    That sucks Ian. I’d be angry. Typically most of us probably get the tiny smd version of the j201 and convert it to through hole. Adapter boards help. I usually just use a small piece of vero and copper tape (cuz I’m classy). Takes some practice but they sound the same. Tayda typically stocks them.

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  5. Ian18 January 2022 at 16:55

    I'll have to look into this, Because it really limits my options

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  6. Tom18 January 2022 at 18:01

    Banzai has them at a reasonable price. Just checked. Shipping is murder for me in the states but may be lighter for the U.K.

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    1. Ian18 January 2022 at 19:29

      Nice! I'll take a look

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    2. Chris19 January 2022 at 16:54

      Bitsbox sell the J201 SMDs and adapters for pennies. Just a PITA putting them together.

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    3. Ian19 January 2022 at 17:54

      I was looking at these... They look pretty cool. I'm not sure how you would solder the pads on?

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    4. Chris20 January 2022 at 01:12

      With great care... Can be done

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    5. Ian20 January 2022 at 08:07

      I'm gonna try it!

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    6. Chris21 January 2022 at 14:15

      It's on my list, parts ordered so maybe be done the weekend, or Tues/Wednesday. Fuzz dog actually sold a 2N5457 so I'm spared the joy of SMD soldering this time :-) . Using a OP7) though, no reliable LM308s anywhere

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  7. D Russ19 January 2022 at 22:14

    Not sure how well they ship to the UK, but I get my JFETS from GuitarPCB. Also Tayda has 2SK30s in stock right now.

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    1. Ian20 January 2022 at 10:01

      There are some to be bought in the UK from mouser but I've read that the ones that are currently left I generally out of spec.

      I do think making them on SMD converter boards is the way forward.

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    2. brain21 January 2022 at 06:38

      I can also vouch for GuitarPCB. been very happy with all the components and boards I've purchased from Barry.

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    3. Chris21 January 2022 at 14:13

      I've got a 2N5457 through hole from Fuzz Dog. Bitsbox still the SMD J201s tip and adapter to convert them to through hole.

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    4. Chris21 January 2022 at 14:13

      Autocorrect made a mess of that.....

      I've got a 2N5457 through hole from Fuzz Dog. Bitsbox also sell the SMD J201s along with an adapter to convert them to through hole.

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  8. Tom20 January 2022 at 11:37

    Mouser’s shipping costs are cray cray too. I think they’re in Texas. I’m in Chicago but baseline price is $10 for even one part. Their search engine sorta sucks too and you’re searching through millions of parts. It’s easy to get the wrong thing from them. I don’t use them unless they have something almost unobtanium.

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  9. Unknown21 January 2022 at 15:02

    If you are after FETs, check out DIY-TUBES.com. He sells Russian FETs (KP303A or B), they are J201 equivalents and sound mint. P & P isnt too bad and worth it if you buy plenty

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  10. brain24 January 2022 at 22:35

    Tag it! Built with the layout values then swapped out for the Sunn tonestack mod. it's super subtle but I think I prefer the latter. Thanks for the layout!!

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  11. Chris30 January 2022 at 17:45

    Build as well. Works sound.

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  12. FuzzDog31 January 2022 at 16:41

    Built this with 2n5457, 2n5458 and J201 at the output. You'd never notice a difference.

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  13. Orion Tonehunt18 March 2022 at 00:01

    Just built this. Excellent excellent excellent ... my favorite RAT variant by far. Took the diodes to a 6p2t switch and went nuts.
    Just save yourself the headache and use a 2N5458 - still cheap and easy to get - compared to 2N5457 and there was zero difference.

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  14. Fred Russom10 April 2022 at 23:58

    Im fixing to build this one. I'm gonna buy a 308 but was wandering what you might suggest me socket and experiment in the 33pf caps place. I have TLO71 and 5532.

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    1. Orion Tonehunt Handwired Pedals28 July 2022 at 07:30

      Hi Fred,
      Sorry this probably doesn't find you in time, but just for reference for others, a TL071 or LM741 would work as a drop in replacement, however, you would actually get rid of the 33pf cap.

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  15. sharery dair23 July 2022 at 12:28

    the right English term for ክልል is biotopes which gave the German term of lebensraum. It a notion derived from zoology . The entire edifice which this ethnic federation is based upon is nothing to the least racial and at most nazistic. Rattery Menifee

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  16. Pedal builder11225 September 2022 at 02:36

    wheres the output?

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  17. Uzume22 March 2023 at 21:23

    to wich Voltage should i Bias the Jfet? i can`t get it bellow 7.2 V...with the 25K trimm...... i see also, that this layout miss the 47R resistor that the OG Rat has on pin 2, before the Ruetz mod, how does that affect the sound of this one? thanks

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