Monday 19 October 2015

Death By Audio Evil Filter

Here is the layout of an unreleased DBA pedal.
You can find the original FSB tread HERE
Thanks to Anders for verifying it!

Here's the video of a clone:




19 comments:

  1. Cool stuff. Actually there is a video, but its a clone. Sounds great though.
    https://www.youtube.com/watch?v=e38n9GYiXwc

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  2. Thanks for the heads up! Could not find it.

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  3. The problem I would have with this build is that there is so much wiring, so much that could go wrong, and unless there was dead silence I wouldn't even know it!!! After all, it's a DBA pedal, it's supposed to sound like shit.

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    1. It's really easy to get confused with how the filter should sound, too.
      My first go at it ended with me burning out UAF42AP, but it still made some sound on certain settings.
      With it working perfectly; for the high pass filter, one end will be so high pitched you won't hear anything while the other end almost has an octave divider quality to it; for the low pass filter, it acts basically the exact same only opposite, plus it has more of an analog octave up sound to it.
      The band pass filter sounds kinda shitty all the way through.

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  4. How are switches wired. I just need to know where the numbers go on the switch

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  5. Call this verified. Great fuzz on this and the filter is pretty good to. Not sure if the expression pedal is doing anything though.

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  7. I'm pretty sure it was officially released as I've got one in its DBA box

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  8. Hey there! First, many thanks for your work.
    Are you sure about how Expression Pedal is wired? What if I want to remove the exp pedal out?
    Also, is the 4x3 rotary right? I don't see anything about how to link the other poles and side of the rotary, apparently it has soldered only 4 of the lugs.
    Thank you !

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    1. Yeah if you look at the schematic its just using 1 main pole, and the 3 throws of a 4P3T rotary to give selections for Low, High, and Band pass off pins 1, 13 and 7 respectively of the UAF42. The expression pedal wiring does not seem correct.

      Looking at the schematic, its a +9v feed going right to the Expression Pot, which also appears to have no series resistance and creates a short to ground, which would bypass the LED's inside the H11F1M's altogether.

      If the frequency pot was set at minimum resistance, which would equate to maximum brightness for the LEDs inside.. would shorting power to ground equate to dimming them on the "supply" side rather than the ground side?

      I plan on building this pedal sooner or later, and honestly I just want expression pedal filter sweeps. That shit sounds bananas. So I'm going to try and figure it out if anyone else cares to weigh in! Thanks guys
      -Brett

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  9. I stupidly bought mpsa05 instead of mpsa05g or mpsa05ra what's the difference between these

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  10. Built this and allis working well except I’m getting charge pump whine despite trying 1044s and 7660s. I used 2n5088 for the transistors and they seem suitable. Haven’t tried the exp pedal yet

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  11. What I thought was charge pump noise seems to be related to the expression pedal out. An exp pedal dims the leds and kills the pedal. With the exp pedal out tip disconnected I’m only getting the high frequency on one of the filter settings, which could be how it’s designed.

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  13. hey guys,

    did somebody do that without the fuzz part?
    or any effetcs similar to its filter part?
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  14. As has been noted, the expression pedal does not work on this layout. I don't know about the original, but I made it work pretty nicely by using 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. This appears to be how it works from watching demos. I also preferred a linear pot for the frequency and not a reverse log.

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