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, February 9, 2018

DOD Carcosa

Happy Fuzz Friday, everybody! Here's a new fuzz circuit from DOD. It's a cascaded transistor design offering a wide range of tones with tons of output. Should be an easy fit in a 1590B.



11 comments:

  1. hi,
    sorry i kwon i'm not in the right place, but i have some questions to ask you about commercial use of yours layouts ! where can we speak ? any chat or private place ?

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  2. Verified! It ran the first time.
    My transistors 2n5089 had 670HFE, the circuit gets too much gain, it gets a lot of background noise, and the distortion is excessive and it loses definition. I made a radical change for a BC549C with 420HFE, the noise disappears but only gave distortion with the maximum pot, I ended up with some BC550C with 500HFE, it sounds a lot like the original carcosa but I'm still not satisfied, I'm going to test more iransistor, but I think the ideal gain will be between 500 and 550HFE.

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  3. I built the tagboardeffects vero and I agree. Transistor gain is crucial on this thing. I have bc109c's around 500ish hfe in it right now but I'm still not satisfied. The noise is gone at least. I'll post back when I hit on the magic #'s.

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  4. Verified on trans 2n5088 with 510-540 Hfe. On the turned at least twirls very soft load, like overdrive. Then there are many harmonics and fuzz. Sometimes, at the maximum settings, a shout appears.

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    Replies
    1. @DeadTree "Sometimes, at the maximum settings, a shout appears." Do you mean transistor oscillation like a screaming or whistle? I experienced the same (with 2N5088 hfe ~550). If I turn down the guitar volume the shout disappear. It's similar to FuzzFactory's behavior. This is really annoying.

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    2. Update! I replaced the BAT46 with BAT41. Now the pedal is more stabile and rigid. Sounds like the original, but the oscillation don't disappear fully.

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    3. i have whistle too, used 2n5088...

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    4. Have you fixed the problem with 2n5088??

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    5. I try, used 2n222 Q1,2,3 but DOD self-excited when i put off guitar, & turn volume max

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  5. Hello all.
    I have tried this circuit two times but it not work OK.
    Big noise and a great coupling with out pot near maximum and before near maximum too.
    I have tried 1n4148 diodes, instead bat41. MI
    I have tried with bc337-25, instead 2n5089.
    What is the problem?

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  6. Built this today and it sounds fantastic. I used A10k instead of A5k for the high cut, and used 2 1N5817s in series in place of each clipping diode. Everything else was exactly per the layout. The high cut does get pretty brittle at higher settings with the A10k, but it also gives a ton of range.

    With respect to noise issues: this thing hissed and buzzed and oscillated and shrieked like a banshee when I first tested it. It has A TON of gain, so I figured I'd box it up and see if that helped before I started swapping components. After putting it in the enclosure with everything shielded and grounded and the wire runs as short as possible it is dead quiet when you're not playing.

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