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Author Topic: circuit design for resonant low pass filter wanted please  (Read 10223 times)

smojo

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circuit design for resonant low pass filter wanted please
« on: August 29, 2011, 03:32:58 PM »

Saw these on Ebay and fancied making something similar. Does anyone know where I can find cct designs please.

M-Z3R0 - K FILTER V2 - resonant low pass filter.
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Dylan

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Re: circuit design for resonant low pass filter wanted please
« Reply #1 on: August 29, 2011, 04:00:54 PM »

Great topic. I've been wanting a nice, simple, LPF schematic lately too. This one looks promising: http://www.magicmess.co.uk/electronics/6vfilter.php
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Re: circuit design for resonant low pass filter wanted please
« Reply #2 on: August 29, 2011, 06:44:22 PM »

do a search on here for synthacon, or search for synthacon filter or something on google
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smojo

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Re: circuit design for resonant low pass filter wanted please
« Reply #3 on: August 30, 2011, 04:49:47 PM »

Thanks guys, the synthacon looks great but maybe a little too complex for me at the moment. The other design does look promising. I'm wanting it to hook up to some circuit bent toys or my nand gate oscillators to add a bit more colour to the sounds.
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jamiewoody

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Re: circuit design for resonant low pass filter wanted please
« Reply #4 on: August 30, 2011, 08:44:32 PM »

i found and ordered these butterworth lowpass IC chips a while back. i wish i could find a citcuit for a lowpass filter with res using one of those. seems it would be much simpler, since the lowpass is already built!
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nochtanseenspecht

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Re: circuit design for resonant low pass filter wanted please
« Reply #5 on: August 31, 2011, 09:22:54 AM »

ms20 filter has a simle design and is easy to clone. there is quite a lot of info on the net about it
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noob666

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Gordonjcp

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Re: circuit design for resonant low pass filter wanted please
« Reply #7 on: March 13, 2012, 09:33:07 PM »

The Synthacon filter is barely any more complex than the Gakken filter ;-)

There are more diodes in the chain, giving a greater frequency range.  Like the MS20 filter and the Gakken filter, it is strongly affected by the DC conditions on the input - and in fact by the input signal!  Set it to be very resonant and stick in a low frequency sawtooth to hear what I mean.

Here is a pic of my prototype Synthacon filter, using bird's-nest construction: http://www.gjcp.net/media/filter.jpg
and this is what it sounds like (watch your speakers, the resonance gets out of hand): http://www.gjcp.net/media/filtertest.ogg
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