Wednesday 1 May 2019

Fortin Amplification Zuul

Original info:
"ZUUL is the most transparent noise gate on the market! Studio quality specifications with simple straight forward operation. The ZUUL’s threshold knob also controls the dynamics of the gate circuit. Perfect for guitar, bass or any signal source as it has studio quality specifications. Use in front of an amplifier or in a series effects loop. Dual colour LED for visual feedback gating action: Green = Open, Orange = Closed, Off = Bypass. The KEY input signal can be directly from your guitar (ex. split from ROACH or SPLIFF) or other signal source which lets you go from clean to high gain without changing the Threshold knob. This powerful feature lets you control the gate with a different signal than what flows through the input/output jacks of the ZUUL. Side switch or internal jumper to change the threshold range if you are injecting a large signal into the input and not using the key input"
You can find PedalPCB's schematic, info and pcb on their website here.



42 comments:

  1. Thank you for this layout! I have a noob question though... What are the yellow things? I don't know that I've seen those before on a layout.

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  2. They are normal capacitors

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  3. this is awesome, thanks alex!
    i just bought that THAT4301 IC few weeks ago thinking "i might have time to make a vero at some point".
    ill try this asap!

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    Replies
    1. Cool! If you don't want the Key Jack, just add a link between the 2 tips.

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  4. The THAT4301 is EOL since 29th of April 2019 and will only be available till Q1 2020. I'm working on a redesign based on the 4305 but that one is only available as SMD (QSOP16).

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  5. This comment has been removed by the author.

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  6. Thanks Alex!
    I'm having trouble finding a 560nF cap, would it be advisable to swap it with a 470 or 680 nF ?

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    1. You could also try putting a 100n and 470n parallel to form 570nF. That will be closer than the 470/680 you suggested.

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  7. Ebay has lots of 560nF caps. Try to find the brand ERO. Seller whazzgroover has some if you want them (no that's not me :).

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    1. I missed your comment and ended up ordering from Tayda. Thanks anyway!

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  8. PedalPcb have a pcb for this and they sell the THAT IC as well

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  9. SMALLBEAR HAS THE THAT4301 CHIPS FOR ONLY 10 BUCKS PLUS SHIPPING

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  10. Where to get the proper LED?? The Fortin changes the color Green to Orange. I've purchased 3 or 4 different LEDs types and they all SUCK!!...cant tell the difference of change, some only look like orange and higher intensity orange, some just look like little points of light, and some are soo bright and clear bezel, like looking into a laser!!! NOT finding a suitable LED. Please provide source and part number. Thanks,

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    Replies
    1. It is not the LED fault.... change the values of the current limiting resistors (both 5k6 top left, going to LED1+, LED2+). Orange is a result of both LEDs being ON in the Bi-color LED. Lowering the resistor value will make a color shine brighter and upping the value of the resistor will make it shine dimmer. You could use a 10k trimpot instead of the resistor for LED1+ and experiment. Once you find the value you like, measure the trimpot and replace the trimpot with the nearest standard resistor value.

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  11. what about wiring if I use three socket jacks

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  12. Well... my pair of 4301’s just arrived!! Now to find the time to try this build out :D

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  13. Built it! works good. I was a little confused on the key jack so I made a switch to short the "key jack tip" and "key jack sw tip" then connected the "key jack tip" to the tip of a mono jack for the key. I flip the switch to shorted if I'm not using it in the FX loop, and switch it on when I am.

    Having it wired to a stereo jack didn't work. it'd short one of the key connections to ground, so I pulled the ground off the stereo key jack and that made it not work at all. They way I have it set up now works great.

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  14. Hey guys, I've built this thing from scratch twice now, to no avail. While I'm not perfect, I'm starting to think that I'm not the problem at this point. I get a faint high-freq. squeal. When I probe with my fingertip under the 1054 it goes away and I hear, very faintly, the guitar sound. I've tried all 5 1054 I have but it doesn't work… they're all from the same batch though. Any suggestions? This is about to go in the "well eff it then!" bucket.

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  15. Can anyone compare this to the ISP Decimator? Any estimate on the cost of parts for this pedal?

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  16. Can anyone confirm this is verified yet?

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  17. Was feeling brave so built this today and all seems to be working as it should. You can tag this as verified. For any having issues with the key jack, you need to make sure it's a switched jack that shorts the tip connections when nothing is plugged in. The one I used was a TRS, but it doesn't matter if you use a switched mono or stereo as long as you just connect the sleeve connection to ground and the key jack tip connections to the appropriate sides of the switched tip.

    The only issue I had initially was the LED, but it turned out I'd accidentally bought common anode rather than common cathode LEDs.

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  18. Would a THAT4301P20-I work for this build? At other forums people have used the very same model but with a "U" in the end. I can't make out the difference and if it has any importance.

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    1. Can’t help with the answer beyond saying mine worked perfectly and the chip has THAT4301P
      A6006B written underneath. No suffix after the P. I think I ordered mine from PedalPCB when I got some other boards.

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  19. Pic of the completed build. I managed to squeeze into a 125B, but didn't wire in a switch, so it's always on (or used in a loop of a switcher).

    https://www.dropbox.com/s/t779hz5zmru2rss/IMG_1669.jpg?dl=0

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    1. Should also be noted that I replaced the knob with an internal trim pot. Its a set and forget pedal for the guy who is using it.

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  20. I can't seem to find a 25k potentiometer. Would a 50k pot with a 50 resistor across lug 1 to 3 be a good alternative? I understand that this would screw with the taper linearity, but are there any arguments against this approach, or better approaches? Btw, many thanks for this!

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    Replies
    1. yes you can, but... go to tayda adn you'll find cheap 25k pots. Mouser, smallbear etc etc.

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  21. I am pretty sure that Theres something wrong With that Led wiring. I talked to some people who build this and i am trying to debug mine, i read the comments here and Watched the Picture of Steve f build and for now and cant say that anyone wired it Up Like shown on the layout and It worked First try. Everybody seems to make some Changes but no one wrote Them down yet. In my build i can say that polarity at the Led is wrong, taking the Led + to cathode instead of anode makes it Work. But than its Just turning on and Off instead of changing color.
    The noise canceling of this pedal is really great so i ll will try to get this to Work properly. Any Help would be appreciated

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    1. I have to correct myself. I got delivered the wrong Led! As soon as i changed Out to another one i ordered to test the new Led Works Just fine. It is Common cathode! And the Led wiring is correct

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    2. Could you post a link to the exact led you used? I definitely had trouble with mine.

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    3. I ordered 5 Common cathode LEDs from eBay. Its a bi-color Led switching between Red and blue. The seller is master_q from Germany. I was Not able to See a difference between Common anode and cathode led's itself ( i ordered both for comparison)it is really hard to Spot this Problem. If it helps i can Upload a Video to YouTube or send you Pics of my build.

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  22. Noob question, what is the red rectangle with the two white dots in the upper left? Thanks in advance!

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    1. It's a single pole single throw DIP switch

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  23. Replies
    1. It stands for Collector, Base, Emitter and denotes the pinout of the transistor - in this case they are all 2N3904

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  24. Question: the led has three leads... Where does LED 3 connect to?
    Thanks

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  25. I'm having a bit of a problem with this one.
    First of, I forgot I had this one and all that was left was to put in the ICs in, I forgot I had them delivered a long time ago.
    But right away there was smoke from 1054, so I removed the ICs and the Transistors and started measuring. I had +9V one some odd pins on 1054 and sorted that by cutting and scraping the copper lines under it.
    But IC1 still gets pretty warm, are my measurements alright? (all ics and transistors removed).
    I've measured from where the ground and +9V connects to the board to these pins (with 1 down to the right on the board):
    IN 8,97V
    1
    2 7,17V
    3
    4 8,75V
    5
    6 8,67V
    7 8,65V
    8 0V
    9 0V
    10 8,96V
    11 8,98V
    12
    13
    14 8,67V
    15 8,67V
    16 0V
    17
    18 8,5V
    19 8,67V
    20 0V

    I did check the orientation of the transistors with my tool and the seem alright.

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  26. Is there a schematic for this anywhere?

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  27. The question is, do we have a new layout with the that4305 which require two additional opamps, now that the that4301 are obsolete?

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