Friday, 21 June 2019

Fuzzrocious Ram the Manparts


From the source:

Ram The Manparts is a LM386 (a power amp chip) overdrive that we built to allow guitarists and bassists to not only drive an amp HARD, but also to add some textures and features to stand out! The voltage sag allows the user to drop the voltage below 9V, creating a glitchy, sputter, Velcro-like sound. Keep it clean, make it grindier/heavier, or make it glitchy…the choice is yours, dude. 

The pedal has since been discontinued and not the cheapest when buying used if you can find them.

On Guitar:


On Bass:








54 comments:

  1. Looks a bit weird. Why is there nothing connected to input of the LM386 pin 3 (+)? Shouldn't the 1n from input go there?
    Is there a schematic?

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    1. good catch. i forgot to save the layout after doing the final shifting of components. the 100nF cap should go to pin 3. i corrected and updated the layout. the schematic was sent to me in confidence, so it won't be released unless the person who sent to to me wants to post it.

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    2. btw, i also shrunk the layout by 1 row.

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    3. Zach, I think the 100n should also go to input :)

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    4. And the 1n is switching between pin 1 and 8.

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    5. damn it, it must have moved. thanks for the catch again. moved the cap up one row. the switch is putting the 1nF cap between pin 1 and 8, as it should.

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  2. Replies
    1. There's 2, they're linked at the blue dot, so both ends in the same hole.

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  3. Hey Zach, thanks for putting this layout together! As always, much appreciated. Looking forward to building this once the layout is sorted out.

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  4. Is "starve" 10 ohm or 10K?

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  5. PS using a 22uF instead of the expensive and more hard to get 25uF will not make a real difference. You could even try a 10uF.
    As the LM386 circuits are all more or less the same, you could replace the 1k with a B1k pot (and an optional 470R in parallel) to be able to alter the gain like the lovepedal purple plexi. It's a nice circuit to experiment with.
    Just google "lm386 circuit distortion". I don't get the semi-myth pricing on the used pedals though...

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  6. This comment has been removed by the author.

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  7. Well, it kind of works.
    https://www.youtube.com/watch?v=hIVJXIe7hbo

    https://i.imgur.com/rNybhAZ.jpg

    https://i.imgur.com/8OCpOTt.jpg

    With the Starve knob all the way up, it's low gain and a little growly. A slight turn brings more gain, less growl. Another slight turn and it's dead. There's a spot right before the dead zone that the first part of the signal doesn't pass but continued playing sort of forces it though, if that makes sense. The switch doesn't do anything.

    Edit: Grammar shitstorm. It's too early to type, I should have used the Preview button.

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    1. is yout 1n on B3 and C3? Can't see it clearly in the picture.

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    2. Yes, sir.

      https://i.imgur.com/rw7Y72W.jpg

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    3. Hmmm. I do not know the schematic, but most other designs have a 10uF instead of the 1n. Maybe worth a try?

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  8. the guy that supplied the schematic informed me of an error in the schematic. the 1nF cap should be 1uF. I made it electrolytic, but you can probably used a standard mylar non-polarized cap too. the layout has been updated.

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    1. That helped the Switch but the Starve knob still reacts the same.

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    2. You may have a bad pot. Try swapping it out for another and see if that corrects the problem.

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    3. Tried 3 different B10K pots and they all react the same.

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    4. well good news is i spoke to someone who has the pedal and they said that's how theirs behaves. that the starve pot really works in the 1st 1/4 or so. eventually the starve pot will cut the signal completely.

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    5. In that case, tag it. Pretty good fuzz, kinda raw sounding. Heavy but not harsh. It'd be cool to have the Starve on a trimmer and make this a 1 knob, 1 switch dealie. Set the trimmer to your liking and leave it be.

      https://www.youtube.com/watch?v=WUiFLEmZ5Ow

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    6. awesome. great work. cheers man.

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    7. All LM/JRC386 effects have that problem. I am not a great fan of these IC's, but some people do :)

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    8. The Distortus Maximus is a good 386 circuit.

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  9. Hi!
    Couod you please post schematic? My build doesn't work, I want to make a PCB

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    1. i stated already that the schematic will not be posted as it was sent to me in confidence. if the person wants to post it they can, i will not.

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    2. I've reversed your vero layout, recreated schematic and designed pcb. It sounds totally sick, can't wait to test it with bass

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  10. Where exactly do you have the 100uF capacitor connected. Can't make it out.

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    1. There is no 100uf. Did you mean 100nF? That one is between A2 and D2

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  11. My previous post was for MTK22

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    1. I used a 100uF and a 33uF in series in place of the 25uF because I don't have one. The 100 and 33 gets around 24.8, give or take a bit.

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  12. Anyone have any ideas on how to tame some of the top end of this circuit? I like the sound, but it's a bit bright for my taste.

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    1. Maybe you can try a small value ceramic cap on the last two stripes where are placed Volume 1 and Volume 3.
      This cap from the output to the ground should be cut some highs: 50pf, 220pf, or 1nF film cap... Large value, less treble.

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    2. Oh yea, that does the trick. Mine had a crazy amount of top end sizzle. I've been experimenting with different cap values. 22nf seems to be the smallest value that I can notice a difference. 1uf is a bit darker, but still usable. If anyone else is looking to smooth it out, I'd try between those values.

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    3. You see? Just to experiment! And I was wrong about the values, it need bigger than I thought.
      With a switch you can connect and disconnect it when you want, getting stock and modified version.

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  13. Just built, haven't yet boxed. Here's a demo:
    https://www.instagram.com/p/Bzl2B91nbG-/

    It sounded best running at 12v, at least through my JC-120. I had to throw a noise gate on; it's not a quiet pedal. The starve, as reported, is somewhat useless, but another frustration to consider is that it is extremely sensitive. If the starve is not sufficiently dialed-in, any voltage drop can cause the pedal to become unresponsive (found this at 9v, 12v and 18v).

    To the post earlier which suggested placing a cap before Vol 1 and 3 (to tame the high end), thanks! I put some sockets on those rows to have options.

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  14. How would one do to replace the switch by a pot ?

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  15. I experienced the same starve issues.... Ended up switching out the LM386 until i found 1 that allowed the starve control to behave like in the demo.

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  16. I built it today, and it sounds very good, fat, warm and quite fierce.
    - I replaced the 1K resistor with a 2K knob, and it's great like that (it allows for much more fine tuning than the switch).
    - I tried to add a 22nF cap before the volume, but i didn't hear any hicut filtering at all. I might try with a bigger cap value (but the "stock" high frequency range was fine to me).

    Thank you all for both the layout, and the mods suggestions !

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  17. Hi guys, this is my second built and I would like to ask you for a little help - I am just testing the circuit on breadboard using LM386L and with 9,12V on battery recieving these voltages: 1,33 0,1mV 4,7mV 0,1mV 1,32 4,30 8,41 3,83 (those three mV are about zero when measuring on 20V span) - do you have any idea what to do..? Thanks for your patience and also forgive me my grammar, we have poor english here in Czechia :D

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    1. ..oh and I forgot to mention the problem: the circuit is dead..

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  18. Put a 2K ohm resistor between lug 1 and 2/3 on the Starve pot to make it have a smaller range (less resistance) to make it more useful. Also make sure to use a LM386 1 or 2, but not a 4. The 4 has a min voltage of 5v 1 and 2 have a 4 volt min....

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  19. Can I use a 1N4007 diode or something similar?

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  20. yep verified.

    used a 5K pot for Starve
    an LM386N3
    22nF's instead of 25's
    1N4007 diode
    and a couple of parallel caps to reach 400pF (closest to 390pF)

    starve at full open gives a nice breakup
    starve at 75% gives a harder fuzzy distortion
    turning the voltage lower results in a synthy fuzz with limited scale, higher notes are inaudible or an octave lower

    anyhow a fun and cheap new pedal

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  21. This thing behaves so much better with a B5k pot for a starve. It still cuts out completely eventually, but not until the last quarter turn or so. I'm wondering if a B2k would work even better?

    Also, the way the starve control is wired is reversed - to my logic anyway. If I left it as shown, I'd call it a 'voltage' control, rather than a starve, but I already had the label done on my enclosure, so I reversed the wiring to make 'starve' accurate :D

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  22. @TedS:
    I used a 2k2 resistor across the lugs on the Starve pot. THANK YOU! This pedal just went from zero to hero. The pot now has a full range of options.

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  23. Hey guys.
    After adding some mojo, I've got a problem. I've added a voltage meter, ground to ground and plus to the starve pot, 5k linear. For some reason this meter works fine for a quarter turn. Anything from 0 to 75% shows 3 Volt. 75 to 100% the meter goes from 3 to 9 volt.
    Is there a wat to fix this?
    Soundwise there is a difference in those first 75%

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    1. Also on lower voltages, the needle jumps when playing

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  24. I disconnected the meter and checken the voltage over a whole turn of the starve pot. Although i used a linear pot, the voltage raise logarithmic, which explains the weird volt gauge readings. The jumping of the needle, could this be fixed with a diode?

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  25. I used a B5K for starve and a 220nf instead of a 1uf in the boost switch. It also acts as a great treble booster.. :-)

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