LPFet VCF by FEEDBACK (optofet VCF)

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strat-1
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LPFet VCF by FEEDBACK (optofet VCF)

Post by strat-1 » Fri Aug 24, 2018 2:40 pm

WE UPDATED THE POST WITH THE ALL THE BUILDING FILES
www.feedbackmodules.com

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Low Pass Fet VCF is an adaptation of a classic low pass 70s design based on VTLs.
While searching to make the circuit ROHS compliant, our team mate Chrissugar gave us the idea to use H11F1 optoFET instead of vactrols.
You shouldn’t consider LPfet as a classic VCF, it's also suitable for shaping, sculpting and distortion.
Treat it like a sculpting sound design tool, you can achieve a lot of unique sounds with it.
As it is based on resistive optofets, you can't have an accurate sine and v/oct as other vcfs, but you can tune the VCFs feedback oscillation
from FREQ pot at the same pitch as the input source, thus obtaining raw, aggressive sounds.
By design, the resonance pot is not answering on its full range, H11F1 response is not linear, so a compromise was made to keep the most interesting sound.
The project contains common accessible parts, so you will not have a problem procuring them.

We used two oscillators slightly detuned as the sound source.

Output with switch in 2Pole position.

https://soundcloud.com/strat1/lpfet-2pole

Output with switch in 4Pole position.

https://soundcloud.com/strat1/lpfet-4pole

LFO inserted in FREQ CV input.

https://soundcloud.com/strat1/lpfet-lfo-modulation

LPfet through VCA. ADSR to VCA and another ADSR for LPfet.

https://soundcloud.com/strat1/lpfet-adsr-modulation

LFO inserted in RESO CV input.

https://soundcloud.com/strat1/lpfet-reso-modulation

LPfet will be available in two type of kits :

KIT1 : 20EUR (2PCBs+frontPanel)
KIT2 : 32EUR (Pcbs+FP, 5xminijacks, 4xpots 50KA, 10KB and 100KB, 3xboard connectors)

Complete module will be 90EUR.

KIT1 :

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KIT2 : kit1 +

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Last edited by strat-1 on Sun Mar 10, 2019 4:31 am, edited 12 times in total.

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paterursus
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Post by paterursus » Sat Aug 25, 2018 5:22 am

You might as well just take my money directly, what little I have left. I'm for a kit 1. This thing sounds absolutely incredible!
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tobb
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Post by tobb » Sat Aug 25, 2018 5:27 pm

Nice,i say!

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Swyndger
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Post by Swyndger » Mon Aug 27, 2018 2:14 pm

Very nice!

So I have two new filter and the noise module to order. And I already have two dozen empty modul-PCBs laying around. Enough to do for upcomming long winter nights ;)

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strat-1
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Post by strat-1 » Sat Sep 15, 2018 6:43 am

[UPDATE] I uploaded the BOM list.
We are doing the final review of the manual, so I will post it very soon.

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strat-1
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Post by strat-1 » Thu Sep 20, 2018 2:42 am

[UPDATE] We posted the building files. :)

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paterursus
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Post by paterursus » Thu Sep 20, 2018 10:11 am

Thanks for this! I can't wait to build mine. I love your build documents, by the way!
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cloudberry
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Post by cloudberry » Thu Dec 05, 2019 4:12 pm

The 4 pole sounds quite boring to my ears, but the 2 pole is fabulous!! Amazing. Has anyone tried it with pads?

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airfrankenstein
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Re: LPFet VCF by FEEDBACK (optofet VCF)

Post by airfrankenstein » Tue Apr 07, 2020 8:44 am

Does anyone have demos or sound samples other than those already available ? I'm still on the fence about this module.

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strat-1
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Re: LPFet VCF by FEEDBACK (optofet VCF)

Post by strat-1 » Thu Apr 09, 2020 1:24 am

airfrankenstein wrote:
Tue Apr 07, 2020 8:44 am
Does anyone have demos or sound samples other than those already available ? I'm still on the fence about this module.
Here :)


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