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, October 21, 2016

Death by Audio Robot

For Fuzz Friday, here's another wild and wacky one from DBA:

The Robot is a low fidelity 8 bit pitch transposer with absolutely no feelings what-so-ever. It is completely synthetic and transforms any input into a spuree of resynthesized robot jargon.

Originals need a dedicated power supply as the HT8950 chip runs off 2.4-4 volts and the power section of the original will not play nice daisy chained with other pedals. To make it a little more user friendly, I've altered the power supply to use a 3.3v regulator (LM1117V33C or similar, though watch the pinout). Here's my modified schematic:





Note: I've also included 4 extra pads on the PCB layout in case anyone wanted to do the mod lvlark describes here.

31 comments:

  1. Interesting....it sounds as made for a wah pedal housing with the pedal-pot wired to the control setting. I especially liked the fx / sounds produced, while turning the control-knob. Another one on my list. Awesome work!

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  2. Wow, this is very nice pedal
    I wish i could build one right now, but i don't have any 8950 sadly

    How about bearfoot candy apple fuzz gold from tagboard for the next fuzz friday? I can verify their fixed layout ;)

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    1. Looks interesting. Can you find an actual schematic? Trying to decipher stripboard is not my favorite. haha

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    2. Sure, I'll look for it and post here

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    3. This one should work https://guitar-gear.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=40804

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  3. Potentiometer "A" its mean linear or logarithmic?

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  4. 4p3t seems wrong to me, why not a 3P4T switch instead? Many layouts around seem not to work... updates?

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  5. hey! awesome proyect.. is it verified? i've seen some builds with a pot instead of the trimpot for gain... i can't decide whether to do that or not as I don't know if it's really worth it... i'd love to hear someones opinion on the matter

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  6. Also thought on adding a exp pedal input to the control knob... i think it would get some weird and interesting sounds out off the pedal... specially in arpegiator mode

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  7. Didnt work for me i get low volume and nothing i do can fix it

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  8. it doesnt work well it needs a negative 3.3 power supply to work propperly i think i built it and is not working well

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  9. Update: replace potentiometer of 100k by 1k for correct operation of VOLUME, JOIN PIN 1 AND 2 OF CONTRO, DO NOT LEAVE
    CONTROL PIN 1 IN SOLITARY

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    2. What does this do though? It doesn't seem to make a difference either way.

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  10. https://www.youtube.com/watch?v=gjJ7p9m8E3k&feature=youtu.be

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  11. Hi, do you think a HT8970 could also work? Cound find a HT8950. Thanks in advance!

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  14. How much Ohms have you set on trimmer?

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  15. Hi ! Thanks for the layout and thanks Dan for your advices !

    - I have set the trimmer at 3/4 , because at full level the noise is heavy, but this control is (for me) not usefull.

    - Remove 470pF on output TL072 is a good way to have some trebles, I have put a switch between the two possibilities.

    - I confirm that A1k for volume is necessary instead of A100k for a good range of control

    - Instead of LM1117 I used a LM1086CT-3.3, same pinout.

    This layout is OK for wire the 4P3T :
    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/DBA/01-DBA_ROBOT_VERO.png

    Simon

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    1. And what about normal mode, btw? In the wiring you gave link to there's two positions for arpegiator. I did everything like pictured.

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  16. Hi all ! Someone has verified this one with the mod ?
    I'll be trying with a rotary switch 1P4T in the right side of the HT8950 ...

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  17. Puede usarse con daisy chain?

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  18. Has anyone ever successfully added an expression input for "control"? I've been trying for a while, and it primarily just behaves like the pot is fully clock-wise (0 ohms basically) with only the tiniest sweep, as soon as you plug anything in. It's all crazy sensitive to interference. I even tried making a special trs cable with shielding between the wires, but to no avail.

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