Pages

▼

Wednesday, February 25, 2015

AMZ Dr. Quack

The Dr. Quack is Jack Orman's improvement on the EHX Dr. Q envelope filter. Basically, there's an added input buffer to increase the input impedance (which is kinda low in the Dr. Q) and offers better range control. Check out Jack's blog post on the circuit for more information and a few mods.


at

21 comments:

  1. AnonymousMarch 19, 2015 at 3:06 AM

    think there is a pad missing on the pcb for the 10k to pin 3 of the ic, it seems to go to pin 2 in the present pcb, so i went ahead and punched one more and i got sound coming thru but i only have some quack when my finger act as a resistor behind the pcb...
    scratched all tracks good, brushed it, reflowed it, changed ic, j201, and 3904...no quack, but no voltages anywhere on the 3904...

    ReplyDelete
  2. dtgehringMarch 19, 2015 at 9:40 AM

    Hmmm... I added the missing pad and went over the layout and schematic again. The only problem I found was the output cap was wrong. I had it listed as 4.7n instead of the correct 47n. Try swapping that cap out, but it sounds like there may be a bigger issue than that...

    ReplyDelete
  3. henji_1November 20, 2015 at 3:29 PM

    its working.. d2 blinks, d1 lights up,..
    great site..thanks..

    ReplyDelete
  4. Giovanny SantosOctober 26, 2016 at 7:09 PM

    Working (very) well. Checked!

    ReplyDelete
  5. UnknownApril 16, 2017 at 8:29 AM

    Hello, I'm looking for EHX Bass Micro Synth scheme.

    ReplyDelete
    Replies
    1. UnknownApril 16, 2017 at 8:32 AM

      I found this, but with no values.
      http://obrazki.elektroda.net/93_1270655319.jpg

      Delete
  6. UnknownJuly 31, 2017 at 4:02 AM

    Built a second one, this time the PCB variant. Had weird noise issues, like if there is sound like wind coming even if you don't strum. Found the problem in an old salvaged foil capacitor (the 1nF). Changed it, now it works like a charm.
    Thanks!

    ReplyDelete
  7. The AplikatorOctober 30, 2018 at 1:37 PM

    found the ehx guitar and bass micro synth schems, http://www.freeinfosociety.com/media/pdf/2090.pdf
    it would be an amazin add here :)

    ReplyDelete
  8. SergioNovember 4, 2018 at 7:34 AM

    what kind of DPDT is necessary?On-On?on-off-on?or its the same?

    ReplyDelete
  9. SergioJanuary 28, 2019 at 3:33 AM

    where is the pdf?i can't find it in dropbox folders...

    ReplyDelete
  10. SergioMarch 27, 2019 at 12:56 PM

    cap to switch6 is 100n or 10n?

    ReplyDelete
  11. UnknownOctober 4, 2019 at 8:46 PM

    hello what are the measures to print the layout? Thnks

    ReplyDelete
  12. RamTMay 10, 2021 at 2:10 AM

    Please, excuse my ignorance. Where does the "LED" wire go?

    ReplyDelete
  13. AyraJuly 9, 2021 at 9:38 AM

    I had weak wah, it will "quack" when I tap the string harder, any solution?

    ReplyDelete
  14. AyraJuly 9, 2021 at 11:41 PM

    I see all schematics on 100nf caps it just 0.01uf(10nf), is it correct?

    ReplyDelete