Wednesday 1 January 2014

JC Maillet Super Full Wave Octaver

Built this to see if it delivers. It does. Sounds sort of like an inverted, bastard brother of the Green Ringer. Just a bit sleeker in its overall feel. All the information needed on this design (and more) is available at JC's site.

A snippet from the page: Ever wonder what F(x) = |x| sounds like ? Of course I'm speaking in terms of the DC-Transfer function of a non-linear wave-shaper circuit ... for those who don't know Spice or network theory very well - this transfer maps out the quasi-static change in DC conditions everywhere in the circuit (currents and voltages) as the input source (current or voltage) changes in same manner ... this mapping, I should add, totally ignores the frequency dependent behavior of the circuit - it's doing the test at DC (0hz) ... this stuff is routinely used to uncover the harmonics generating capability of non-linear analogue gain stages ... 

To build yours with only one pot, you'll need to swap the lower left hand side 15K resistor with a 100K and replace the "Control" pot with another 100K resistor. I'm calling the pot "control" as it doesn't have a designated name on the schematic or in the description. There also added 1M pulldown resistor at the input, as well as added polarity protection diode. I used LM358 opamp, but i do believe you should be fine with JRC4558, TL072 or any other dual opamp with the same pinout. Oh. I also recommend to use 10K lin pot for the level. That's why it is listed as linear on the layout.


14 comments:

  1. woot! 2014 delivers!
    suggestions where to find vid for this? or just listen to green ringer?
    HNY!

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    1. It's very different from the Green Ringer, although there are some similarities.. And i didn't even look for a demo.. But it is a simple and quick to build :)
      +m

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    2. o? coz the intro said... aaah, what's it matter anyway? I'll just give it a go.

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    3. :) You should be done in less than 30 minutes :)
      +m

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  2. There's an audio only recording here ...http://www.diystompboxes.com/smfforum/index.php?topic=87845.0

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    1. I'm on my android phone right now and that won't load the page linked to at diystompboxes. As soon as I get to use my pc I'll have listen. Thanks for that tip.

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    2. on a pc now. won't load here either. I'll post on the diystompbox page.

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    3. Gah, sorry. I was on my phone too but was told it should work on a pc... now I'm on my laptop and it's dead here too.... shame, I really want to hear this too.

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  3. I built this last night. It has a nice octave but the sound is splatty and the notes decay really quickly. I used a 4558 that was laying lonely and discarded at the bottom of my parts drawer. I may try a different IC. One question - what does the 39p cap do? I didn't have one so I chose a 47p (I had a 22p as well). Either way, I will keep messing with it. Thanks

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    1. i am curious too. i have a closer value than the 47p to substitute, but wanted to know if subbing the 39p for 40pf would be detrimental. any update on your build? what was the verdict with the IC chip?

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  4. Which may be analogues 1N5817?

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    1. That's just for polarity protection, so you could use any diode in it's place. 1N4001-1N4007 are good candidates.
      +m

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  5. hey mates,
    well i build this and it sounds pretty fuzzy with horrible fast decay.
    i subbed the 39pf for a 33pf.
    i tried a jrc4558 and tl072, i liked the tl072 more but both don't really sound amazing.
    i tried a few pots eventually going with 50k lin for level and 250k lin for control.
    i'm not really sure what the control pots suppose to do, its basically sounds like a gain control.
    have i done something wrong or is it just a bad sounding pedal ?
    btw the demo link doesn't work any other demos out there?

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