Monday 17 July 2023

F'Deck / Broughton Hybrid HPF

 Another guest appearance by Sebastian who generously shares his interesting designs!

Here is a snippet of his description for it:

...hybrid of the F'Deck (series 3) and the Broughton high-pass filters. I wanted the steeper slope of the F'Deck (24db/octave below 35Hz) with the gain boost of the Broughton—so, here it is!

 

 

 

 

10 comments:

  1. Very happy to contribute, Anders! I hope others find this one as useful as I have. Not the most intriguing or exotic circuit, but indispensable for all the stoner & doom folks out there: it *really* helps cut the mud, stopping the guitars & bass from stepping on each other, plus makes your speakers run more efficiently (and, thus, more loudly).

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  2. planning to add to this build a split and blend with phase inverter to make a really useful bass tool!

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    1. I would actually recommend NOT doing that. It IS a bass utility pedal: it's a high-pass filter to cut the subsonic frequencies that waste a lot of energy & that speakers often have a hard time reproducing. A blend would only reduce the effectiveness of the filter, and a phase inverter would (more or less) cancel out the main signal & leave only the unwanted subsonic frequencies.

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    2. the thing is, this is going to go in a signal splitter, one is going to this efect and then to a send (pedalboard) then the return would be mixing with the clean signal. So in the bass wouldnt be any low signal messing with the distortion and modulation and I would have the clean signal untouched.

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    3. Okay, there are a few things to explain in this case...

      1) this pedal is a simple EQ pedal that only does one thing: cut frequencies below a certain threshold. Blending an EQ'ed mono audio signal with a "clean" mono signal will, at best, minimize the effect of the EQing or, at worst, create some strange comb-filtering because of the unequal phase relationship between the two signals. Here is a quick explanation of what comb-filtering is—
      https://www.youtube.com/watch?v=osig1c4QcmI

      2) adding a phase inverter to this pedal and blending it back with the uneffected signal will be adding 2 identical *but out-of-phase* signals to each other, which will result in signal cancellation. Here is a quick explanation of polarity & phase in audio signals, and how signal cancellation occurs—
      https://www.youtube.com/watch?v=IrXHVWPGdeQ

      I understand what you're trying to achieve here, but the best use of this pedal in a bass signal chain is in the last place on your pedalboard, right before going to the amplifier. Think of it as a "mastering" tool for your bass signal, coming *after* all the other mixing & effecting has been done.

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    4. ive used the broughton high/low pass for this apllication and it worked great, but found that the low pass to be useless in my case. I dont know why this case would be otherwise

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    5. Alright, do what you gotta do.👍

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    6. Ive build it and it works as i thought. Ive raised the hp cut frecuency, and now I have all my pedals working without low end messing with the distortion, and a clean bass mixed at the end. also conected 2E into 2G, seemed to be that way in the schematic. Really useful for the aplication I was thinking of! thank you Sebastian!

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    7. Excellent! Clearly, abstract debates about use don't matter if it works in the real world, ha ha ha!

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    8. following up with this, Ive end up using this layout and replaced the high pass filter with a low pass filter; and with the one Ive built previously, and with a two loop mixer with phase inverter, Ive build myself a KMA tyler. It works really well!

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