Friday, 23 October 2020

Dead Astronaut Faze Filter

 Requested by Alltrax74, a phaser based on MXR Phase 90 with some bells and whistles. 

Schematic is avaiable HERE

Note that the J FETs should be matched for best effect and CLR 1 value is 47k in the schematic but you could probably go lower if you not using a super bright LED 





23 comments:

  1. Hi.Put link in place of 10n (M22-I22).

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  2. Ah ah ! Thanks man you rock :)

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  3. Ok, I went through the layout with the schematic :
    - There should be a cut under either D1 or the link from IC1-4 to ground (to separate 680k from 47n)
    - Mix Vibe 1&3 shoould be inverted
    - Same for Switch 1&3 (but I guess here that makes no difference)
    - Rate CLR is 47k, maybe it's worth mentionning it as a note, as it's not common to have such a high value
    - As for the phase 90, I guess the 5457 should be a matched quartet
    In any case another very well put layout !
    I'll have to order parts and should be able to start building it in a couple weeks :)

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    1. Gotcha! Added some info, a cut and swapped the lug connections.

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  4. I built it, so far no phasing.
    Audio signal passes, clean output. Only the volume pot works at it should. Some light volume variations with the mix-vibe pots, bias and depth do nothing. Rate led barely lights with the 47k CLR, but flashes and flash speed varies with the switch and speed pot.
    I use TL082 but that should be ok, I tried with a random set of 5457 and a matched set of 5952 i have in a phase 90. Same result

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    1. thanks for giving it a go.

      I'm away from home for a couple of days but will check the layout vs. schemeatic when I get back.

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    2. Ok I have some phasing, but still not quite there. After looking again at the schem, the rate CLR is 4k7, not 47k (my bad).
      So i replaced it accordingly. Still nothing with the 5952 matched quartet. I put back the 5457 and now got some phasing, but only when bias pot is rolled back, depth full CW and mix-vibe somewhere around the middle position. Vol and speed work as they should. I asked the guy from deadastronaut on his YT demo if the 5457 really need to be matched as there is no such info on his build doc. I went over my build a few times and didn't see any error (which of course does not mean there is not)

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    3. Here is DA's answer : "You can, but luckily i havent had to do that and ive built a few of these"
      So, a random set of 5457 should be ok

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  5. Hi.I did and works fine,so it'verified. Add to the notes Mix Vibe 50k B.I used matched chinese J201s,with 2N5457 l found the same problems described by Alltrax74.Successful operation depends on Jfet.

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    1. Ok, I got it to work by swapping the 5457 for a random set of SMD J201, thanks for the tip !
      Compared to my phase 90, phase intensity is almost the same, maybe a bit lower. Next step will be to match these J201 (I have a dozen) with a JFet matcher.
      Still, I don't get the purpose of that Mix-Vibe pot, effect phases only around it's center position. Do you experience the same ? If not what does this pot do ?

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  6. So, I spent some time sorting J201s :)
    https://i.goopics.net/eE8DD.jpg
    I got 4 sets within 10-15% margin, i put in the Faze Filter a set that mesures 70-76mV
    Better result, phases as it should i guess now. Mix-Vibe seems to have more effect but i'm still a bit confused about what this pot controls...
    Audio taper doesn't seem right for the speed, rate is very slow until it gets suddenly fast. i might try a lin there.
    Thanks to both of you guys :)

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  7. Hi Alltrax74. Thanks to you for identifyng the missin cut.In my build the Mix Vibe control works as a blender ,rotated clockwise it emphasizes phasing,counterclockwise it looks like a chorus.

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  8. Hi.1MC is perfect for speed. 1MA and 1MB are not good.

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  9. Hi.I am very satisfied with how it works. The chinese J201 measure 0.30mA-210mV.TL072 obtained from musikding.de. Best regards and good jobs.

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  10. Hello . What software use for layout ? Thanxxx

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    1. I'm using DIYLC G3 V40.0. There is a newer version to download.
      https://github.com/bancika/diy-layout-creator/releases

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    2. Thanks guys for your build reports. Added a note for regarding the Speed control.

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  11. Hi Fuzzhead, although I may buy his board to support his great job, Rob from DA lately released his Astro Flanger Filter, if you feel brave enough...:)
    https://deadastronaut.wixsite.com/effects/copy-of-skyscape-chorus

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    1. Oh c'mon:-).
      Looks very cool but I can't promise anything. It is definitly on my "to-try" list, though.

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    2. You have to have a flanger on your blog, you know it :D

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  12. I built this a while ago and couldn’t get it going. I had a hunch that smallbear gave me four matched 5457s. They were too high gain to use in anything else anyway. They had. Fired up. I’ve never built a phaser before. Lucked out. Didn’t even build a fet matcher to test em. Now if only I could be lucky in the parts of my life that matter. Doh!

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  13. Built this with j201 smd from tayda (unmatched) and it phased right away - very happy how it sounds, I find all the knobs to be very useful. Thanks for the layout!

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