This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Friday, September 18, 2015

Fulltone 70

For #fuzzfriday, here's the Fulltone 70 fuzz. Like the Fulltone 69, the 70 is a tweaked Fuzz Face circuit, following the silicon version. Like the original silicon Fuzz Face it uses BC108 transistors, though others can be used. Q2 should be higher gain than Q1. One of the nice things about the 70 is the added Mids control, which adjusts the some of the voltage reaching Q2 and the output capacitor. You can board mount the pots using right angle PCB mount types from the solder side.





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25 comments:

  1. CharlsRTSeptember 19, 2015 at 12:50 AM

    oh yeeeaahh!!! :D

    ReplyDelete
  2. caseyfumi27November 16, 2015 at 9:00 PM

    Works like a charm. My favorite fuzz so far. Thanks for the layout bud.

    ReplyDelete
  3. JaseWHNovember 16, 2015 at 10:36 PM

    I'm still having issues.
    Getting throughput, fuzz activate when it's hit hard, but dies immediately. Can't quite figure it out

    ReplyDelete
    Replies
    1. dtgehringNovember 16, 2015 at 11:02 PM

      Sounds like mis-biased transistors. Which ones are you using? Have you played with the trimmer much?

      Delete
    2. JaseWHNovember 16, 2015 at 11:30 PM

      I'm using Bc108c's. The trimmer doesn't seem to to affecting anything.
      The 108's I have a reasonably high hfe, averaging around 540.
      I do have some others or I could also try some 7777's.
      Any ideas?

      Delete
    3. caseyfumi27November 17, 2015 at 12:48 AM

      Mine took a bit of trial and error to get a good set of trannies. The BC108B's I settled on ( from TAYDA) ended up being around 170-200 hfe. Sound just a bit smoother than that outright in your face fuzz I got with some 2N2222A.

      Interesting you mentioned the trimmer. I cant get my C to get down around the 4.5V so maybe we need to play around with it...

      Delete
    4. JaseWHNovember 17, 2015 at 1:08 AM

      Lol 7777 😜
      Just realised I'm note seeing anything on C of Q2

      Delete
    5. caseyfumi27November 17, 2015 at 1:21 AM

      Alright, I removed the 5K trimpot and replaced it with a 50K. Adjusted the C of Q2 to 4.5V and the trimpot is reading 25K of resistance. Result, a fair bit more sustain... smiles all round.

      Maybe give that a try JaswWH.

      Delete
  4. JaseWHNovember 17, 2015 at 1:37 AM

    Legend!!!

    ReplyDelete
  5. JaseWHNovember 17, 2015 at 2:08 AM

    Just curious, the trimmer can only go in one way right?

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    Replies
    1. caseyfumi27November 17, 2015 at 2:16 AM

      Yeah can only really fit one way. Center pin (by itself) down on this layout.

      Delete
    2. JaseWHNovember 17, 2015 at 2:26 AM

      Yeah cool! Just eliminating any foolish mistakes!

      Delete
    3. caseyfumi27November 17, 2015 at 2:31 AM

      Hey if you want foolish mistakes I'm your man... :)

      Delete
    4. JaseWHNovember 17, 2015 at 2:43 AM

      Hahaha

      Delete
    5. JaseWHNovember 17, 2015 at 9:05 PM

      So, foolish mistake rectified! Hairline connection across the trace :/
      Sounds good! Left the 5k in who's doesn't seem to change voltage to C of Q2 at all?

      I also only had a c10k on hand.

      Delete
  6. sergioApril 4, 2016 at 6:59 PM

    hello, you could post the circuit Fulltone Full drive II. Thank you

    ReplyDelete
  7. andrea83March 4, 2017 at 7:08 PM

    Hi! I made it and it sounds very nice! thanks a lot! I would like to try with 2sc1815 (as written in the project) but how can I put 2sc1815 since they are ecb and not ebc?!

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    Replies
    1. Effects LayoutsMarch 5, 2017 at 8:05 PM

      Easiest way is to just bend the legs around so they're CBE. Just make sure the legs aren't touching each other.

      Delete
    2. andrea83March 8, 2017 at 6:41 AM

      ok, maybe I can put some insulating tape on them? thanks!

      Delete
  8. JaseHJune 27, 2017 at 10:08 PM

    Does anyone know how I could get a a little more top end into this??

    ReplyDelete
    Replies
    1. Effects LayoutsJune 28, 2017 at 9:19 AM

      Try reducing the value of the 2.2µ input cap to like 1µ.

      Delete
    2. JaseHJune 28, 2017 at 8:11 PM

      Brilliant!
      Thanks dude :)

      Delete
  9. SergeJuly 8, 2019 at 9:22 AM

    Hey folks, I damaged my old big box version, the fuzz pot cleans completely off after 3/4, I read about the replacement value which is 1K log rev, is it anything special or different to a normal 1K pot?

    ReplyDelete
  10. Desde la cima del rockJune 4, 2023 at 1:10 PM

    I think there is a small bug. The anode of diode 1 should be connected to terminal 2 of the Fuzz potentiometer.

    ReplyDelete

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