Tuesday, 17 August 2021

Death by Audio Evil Filter

 

 
The layout above is still unverified but I did a smaller simplified version a while ago. The fuzz section has been removed since didn't care for it. Less offboard wiring and and a smaller enclosure...and you can put your favorite fuzz after it.
 

 

43 comments:

  1. It's a wonder the commercial, "final" version if this still hasn't been traced.

    I'd love to help verify this version if I wasn't already building the tagboard layout.

    As for the expression control, someone there btw suggested a solution for the exp pedal that I'm gonna try once I finish it:

    a trs expression pedal as a voltage divider that lowers the 9v going into the optocouplers. If you pull the diode that is pointed downward and use a switched input jack to give it 9v when unplugged and the lower voltage from the pedal when it is present. I used a 50k expression pedal and added a 62k resistor to 9v and a 33k resistor to ground to fine tune. This way the max (toe down on the sweep) is set by the frequency control."

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  2. Nice layout as always!!

    I have a version of this that I built from Tagboard but that single filter circuit layout is v intriguing. ESPECIALLY if that tip above works! Adding this to the list :)

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  3. Have you built the lite version fuzzhead? Mine isn’t working yet, but I don’t trust my uaf42ap so am getting another.

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    1. Yes, I have built the Lite version. It is boxed and it is rocking. Pity about the ual42ap...they are not cheap:-/

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  4. Great. I think my problem is I did buy one for cheap. Thanks.

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  5. Got my Uaf42ap and now it’s working. I’ve found this very picky about which voltage chip works. Some added a lot of self noise, but I’ve got it working good with a tc1044scpa. Would you just add a cut to use a lt1054? Those never give me trouble.

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    1. Yes, for the Lite version you can add a cut between pin 1 and 8 if you want to use a LT1054. However, the full layout would be a bit problematic...

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    2. where did you get the uaf42ap ? Mines are probably fake. Thanks.

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    3. Got mine from ebay. The seller was tevatronix. I built two. Both worked fine.

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    4. You can also get them on Mouser

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  6. Hi Anders, I am having a go at the big layout but need help with the wiring. Fuzz Output 3 to Fuzz Switch - is this the output on the Fuzz Footswitch? Filter Output 3, does that also go to the output on the Filter Footswitch? Many thanks in advance

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    1. Also, two inputs - i guess one if Fuzz input and the other is Filter input? If I've missed anything please let me know, especially the remainder of the footswitch wiring. Cheers again

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    2. Hey Ian. I will update the offboard wiring info when my mind is clearer. Pretty sick at the moment and its best not giving any advices that might cause you trouble.

      Cheers.

      Anders

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  7. Get well soon mate and no worries about the wiring, its all sorted!! Fuzz section working a treat (not the best fuzz but it works), big chip should arrive tomorrow so can get the filter section going.

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  8. This is all verified mate, not a great fuzz but a cool filter. Many thanks Anders

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  9. Has anyone managed to get the expression control working? Cheers

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  10. Still playing with this but can't get the expression part going. Its defo worth playing with the transistors in the fuzz, I used a mix of MPSA05, 2N2222 and 2N3904 and it sounds good. Its also worth changing the Freq from 500KC to a 500KB. Defo a keeper!!

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  11. Would you mind sharing the filter schematic? Cheers

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  12. So I just finished the lite version. Some awsome stuff here, but... somehow it seems that the Freq knob only works from 0-3. Past 3 the pedal goes silent. Any ideas?

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  13. Well, mine works great, sort of.... can't help but notice the Frequency knob is wired backwards, should be boosting the higher frequencies as you turn the knob clockwise, instead it boosts the higher frequencies as you turn knob counter clockwise, makes sense why a prior commenter only notices the frequency knob functioning in the first 1/3rd of the knob throw, same as my box, this is not how the Evil Filter functions, hopefully flipping the 2 wires going to the frequency pot solves this... will report back as I just fired this thing up.

    Waiting on an EP-3 to show, prior tip in regards to expression should work if you replace D2 with a jumper, send tip of switched expression to A19 with 62k series resistor and ground of switched jack to A2 with 33k series resistor in the Lite schematic. Insulated switched jack would be needed for the task. Will report back after my EP-3 arrives and a bit of troubleshooting.

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  14. ..... and thanks for the blogspot, wish I discovered sooner, built your FZ2 EQ layout and that thing slays with the proper FETS

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  18. Nevermind, I'm retarded, didn't see the video of the older Evil Filter up on Tagboardeffects, seems that one functions differently from the newer one in regards to freq and res. Played a newer evil filter this week and both of those controls worked in reverse of my build.

    Should probably play with pots a bit, my guess is the newer DBA unit uses Log pots, the newer box seemed to have more range in the higher frequencies, and less spread in the hardly audible sub bass range. With the anti log pots it seems like all of the treble frequencies get bunched into the first 1/3rd of the pot.

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  20. Played with the pots, with negative results. Seems this layout is based on a prototype possibly? As the DBA pedal freq and res knobs are quite a bit more functional with more sweepable range on the DBA unit, and those controls work clockwise as well on that box, outside of that, my pedal functions like the one in the tagboard vid.

    It works, I guess, but definitely like Oliver's market offering a bit better... just not the size and price tag. Built the light version and go it packed into a 125b nicely. Could even squeeze the full version in a 125b with careful planning.

    Hope DBA's market offering get's traced one day, and maybe the tip in regards to EXP works, as thats your typical CV control layout I've seen in the modular world. Just waiting on an EP3

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  22. Soooo much wrong with this layout. So far lugs 1 and 3 on Res, Freq, and Hi/Norm switch need to be reversed to function in the same manner as market Evil Filter, even pins 1 and 3 are backwards on the filter selector if you are orientating your selector knob in the same manner as the stock unit, flipping the switches 180 is a quick fix, but the pots need rewired.

    Not a chance 500k is correct for the Freq pot, this pedal was designed to be used with an expression pedal. Most expression pedals on the market are 50K Linear, and the Freq pot should match that, so far I get very limited expression control with a Moog EP-3, and 500kc pairing, using an insulated switched jack running tip to wiper of the freq pot, and sleeve to ground. Every other suggestion is a wild goose chase and results in sending 9v to 0v almost instantly, removing diode 2 as suggested prior removes polarity protection from your fancy medical grade IC's, and allows more voltage through hitting that frail ass 1044 which should most definitely be swapped for an ICL7660s

    Typical expression control layouts are explained here...

    https://griffineffects.com/info/how-to/add-a-expression-pedal-jack#:~:text=Inside%20the%20pedal%3A,other%20legs%20of%20the%20jack.

    Still working out the expression issue, but will have to wait on the right pot, before i start hashing out whether this pedal utilizes TS or TRS expression, this layout indicates TS, as there is no "ring" connection anywhere.



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    1. I don't know man. The layout matches the schematic for the Evil Filter V1 drawn by Mr. Ackermann himself. There is no schematic avaiable online for the current version but I bet it contains quite a few improvements. But I guess you could mod it to suit your needs?

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    2. my buddy wants me to squeeze one into a 125b. He has the market big box he'll off as soon as I accomplish it.

      The controls are reversed in this layout, look at the Freq span printed on the DBA unit, it starts at 0 hz counter clockwise to 10.5 khz clockwise, to accomplish this, you need to switch the wire from Freq lug 1 to lug 3, same with the Res pot, had to change the wire on lug 1 to lug 3 to get it to match the higher resonance going clockwise like in the production unit.

      The expression seems to only work 1 way, with tip going to wiper. I only have about 10% sweep pairing the 50k Moog, with the 500k freq pot. Hoping the 50k match gets me squared as Griffin suggests.

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    3. Also understand this layout is based on Olivers original box, which had me confused for a minute, as my understanding is the schematic comes from a frozen Youtube clip that someone drew out, but the datasheet surrounding all those pricey IC's are cut and dry on how to use them, any changes made to the production model were made in the way the pots were wired, as I've learned, as I've about aped the production model with the changes I've made.

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  23. I've also never even seen an example of Oliver's original creation, and if the schematic was indeed taken from a frozen youtube clip, and 123 got confused for 321, then the clone in the tagboard video was backwards to begin with, and everyone is rolling around with janky resonant filters that don't sound right.

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  24. I'll report back eventually after the UPS man drops off my stuff, about got this thing firing right... I've noticed a Czech builder on youtube has a proper clone, most others sound way off...

    https://www.youtube.com/watch?v=J8xbHLx1Jcg&t=147s

    My pedal functions exactly as this clone and the market box, just need to iron out expression compatibility , the few gut shots I've seen indicate TRS, that open lug on the freq pot may just need to find its way back to ring on the switched jack as well. Will be a week before I can play with pedals again.

    Appreciate the hard work Anders, I don't have the patience for layout creators, but all my builds from you always fire the first time, and can usually work out from there.

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  25. 500k it is, might as well run a volume pedal as an expression. "Ring" is missing from the layout. Only gutshot I can find of Olivers unit comes from an ILF thread from years back....

    https://www.google.com/url?sa=i&url=http%3A%2F%2Filovefuzz.com%2Fviewtopic.php%3Ff%3D149%26t%3D33006%26start%3D252&psig=AOvVaw1IIyf0nSQQsMNq3X2tNYp_&ust=1711805436894000&source=images&cd=vfe&opi=89978449&ved=0CBIQjRxqFwoTCJC096nKmYUDFQAAAAAdAAAAABAE

    Looks like an Amphenol switched TRS jack, specifically ACJS-MIVS-3S. Pic is a bit blurry but I'm interpreting sleeve to ground, and the ring and tip as jumpered together with tip of the switched jack going back to Freq lug 2 and freq lug 2 would need to be jumpered to the open freq lug 3 so toe down/up has a return path.

    50k tames the pedal, not happening. Haven't tried the TRS configuration yet, as I only have a TS jack at the moment, as I ordered parts via the layout. In TS configuration, I'm stuck mid sweep with very little movement.

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  26. For anyone looking for the schematic source, have at it, lol....

    https://youtu.be/5RPo2Te_f4Q

    Definitely try out the filter pot recs, the ILF thread that hosts most of this info seems to report users trying to flip the OG as it wasn't very intuitive, only a few of those were made.

    Typical TRS setup should get you expression control if your build is right, good luck.

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  27. TRS works for expression control, 9V and Jack "Tip" need to find Lug #1, so insulated jack will be required, or expect lots of noise. Jack "Ring" goes to Lug #2, and Jack "Sleeve" goes to Lug #3, with all connections made at the Freq pot.

    For proper Freq/Res pot functioning, same rules apply as if you were playing with a Rat filter, flip those leads between #1 and #3 and you have a properly functioning box, that sound like the market version.

    TRS connections remain the same regardless of Freq pot wire orientation.

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  28. TRS sleeve and tip can also be reversed for CW/CCW preference, I prefer typical TRS configuration, with reversed Freq/Res wiring for production version functionality.

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  29. Great work, braaandooo... can you summarize the mods in a list format for us noobs, perhaps let Anders "correct" the layout? Have a hard time gathering the stuff you did!

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  30. Gonna give this is a shot this fall vacation.
    Correct me if I'm wrong, braaandooo, if you see this.

    So to summarize, in order for it to work right you need to:

    - Swap the wiring on both pot lugs (Res & Freq) 1-->3 and 3-->1 for it to function like the production model
    - Keep the 500k pot, as lower values tame it
    - Reverse wiring on Hi/Norm switch
    - Do NOT remove diode 2 as another mod suggests as it protects from reverse polarization voltage
    - Change the regulator IC 1044 for ICL7660s (better quality)

    Expression pedal
    - For the expression pedal jack, use an isolated switched TRS jack, that is a jack that has a tip-ring-sleeve.
    - Use a 500k volume pedal as expression pedal(?)

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  31. - Wire the TRS-jack as such: Tip to lug 1 of Freq pot, ring to lug 2 of freq pot and finally sleeve to lug 3 of the freq pot.

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