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Korg Minilogue Modifications (sound engine)

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Maffez
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Korg Minilogue Modifications (sound engine)

Post by Maffez »

Hey - I scored a Minilogue yesterday and started toying around with the sound engine (because I can't help myself, can I....). Started to put together some first findings and ideas, including sound clips, here: https://maffez.com/?page_id=2471

Didn't want to hijack the computer controlled minilogue thread (intimidatingly nerdy material in there!) but thought maybe others want to chime in too, so here we go - hardware/case hacks welcome too, but there are some already, so let's have this one about sound!

so far I did filter input boost and level loss compensation for high-resonance sounds; also VCA input boost (don't like that one too much)

Planning on different filter responses (pole mixing) and maybe CV control (might be more complex since internal cv ranges are from -3.3v to +3.3v for most parts) ... looking forward to it!
burgerboy
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Re: Korg Minilogue Modifications (sound engine)

Post by burgerboy »

Following with interest 👍

Is there any potential to increase cros mod depth, it feels kind of too polite, never really gets as nasty as id like.
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

burgerboy wrote: Thu Jun 30, 2022 6:48 am Following with interest 👍

Is there any potential to increase cros mod depth, it feels kind of too polite, never really gets as nasty as id like.
Hey! Yep, that's possible - have attached a short clip of increased crossmod - you basically reduce the value of each R351 (47k, on the back of the pcb) to half or lower (easiest way - wire another 47k across, so when turning up xmod pot to middle you get exactly the old maximum)
XMOD_15K_Across.mp3
(2.2 MiB) Downloaded 6 times
where stuff get really cool is when you mix in one modulator from another voice :)
Criss_Cross_modulation.mp3
(1.29 MiB) Downloaded 6 times
burgerboy
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Re: Korg Minilogue Modifications (sound engine)

Post by burgerboy »

Maffez wrote: Thu Jun 30, 2022 12:56 pm
burgerboy wrote: Thu Jun 30, 2022 6:48 am Following with interest 👍

Is there any potential to increase cros mod depth, it feels kind of too polite, never really gets as nasty as id like.
Hey! Yep, that's possible - have attached a short clip of increased crossmod - you basically reduce the value of each R351 (47k, on the back of the pcb) to half or lower (easiest way - wire another 47k across, so when turning up xmod pot to middle you get exactly the old maximum)

XMOD_15K_Across.mp3

where stuff get really cool is when you mix in one modulator from another voice :)

Criss_Cross_modulation.mp3
You are the best! This sounds dope!
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

burgerboy wrote: Thu Jun 30, 2022 3:37 pm
Maffez wrote: Thu Jun 30, 2022 12:56 pm
burgerboy wrote: Thu Jun 30, 2022 6:48 am Following with interest 👍

Is there any potential to increase cros mod depth, it feels kind of too polite, never really gets as nasty as id like.
Hey! Yep, that's possible - have attached a short clip of increased crossmod - you basically reduce the value of each R351 (47k, on the back of the pcb) to half or lower (easiest way - wire another 47k across, so when turning up xmod pot to middle you get exactly the old maximum)

XMOD_15K_Across.mp3

where stuff get really cool is when you mix in one modulator from another voice :)

Criss_Cross_modulation.mp3
You are the best! This sounds dope!
:tu:

More goodies underway - just got a rad babdpass vcf out of it last night


///

Cv for internal vcas and such.. not surehow to best go about inserts that scale incoming cv to -/+3v… if anyone has ideas….
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SphericalSound
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Re: Korg Minilogue Modifications (sound engine)

Post by SphericalSound »

I,ve been digging your site. Top notch content. It seems you have hacked the half of the available synths and a good part of the non currently available as well. Nice!

I´ve bulit a pharmasomnic sy-core mk2 too. Before killing it (by inadvertly plugin the pcbs in a wrong way!) I discovered a super easy mod too. You can basically do VCO 2 to accept voltages just with a 100k resistor or something similar, I dont remember now. Obviosuly it dont track 1v/oct but it expands greatly on what sounds you can get from the module, as IIRC vco 2 is always running at 400hz fixed frequency or similar
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

Thanks for the kind words, sphericalsound! Yeah, i got so much out of those old music machines/ cykong etc. pages that worked without subscriptions and influencer vibes, so that’s a bit of a homage…

Should update my cy-core page a bit/ finally get to tinkering an extension panel. Define range for Vco 2 is great! And I found some oscillator sync modification that sounds ace…

////

Back to Minilogue — waiting for some switches then I’ll fit some final versions of bandpass filter and mod between individual voices
burgerboy
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Re: Korg Minilogue Modifications (sound engine)

Post by burgerboy »

Holy shit man you are on fire, that latest vca control input mod makes that envelope sound great, could a similar mod work on the filter envelope?

The multi output for each voice is great too, im envisioning a little stereo mixer with individulal panning for each voice going in the spare space next to the main board. I dont know if such a mixer could be passive, but would be cool.
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

burgerboy wrote: Sun Jul 03, 2022 10:22 pm Holy shit man you are on fire, that latest vca control input mod makes that envelope sound great, could a similar mod work on the filter envelope?

The multi output for each voice is great too, im envisioning a little stereo mixer with individulal panning for each voice going in the spare space next to the main board. I dont know if such a mixer could be passive, but would be cool.
I like that VCA mod too - similar trick also did a lot with the mfb synth pro.

As for the filter - cv mod would also increase cutoff pot response and keytracking. Those three signals are done digitally and then sent together as pwm signal, so there’s no way to increase env depth separately from the two others. Will Test nevertheless with one voice but I don’t expect that to sound super useable.

As for panorama: there’s a classic panorama mod (even with a pcb kit for order) for some of the old polys - opamp buffer, trimmer/pot, summing amp. Not sure if this would play very well in a passive setup. Another thing to consider instant your panning will be as set per trimmers, so if you don’t have them accessible somewhere (say, on the back) that’s set and done… might still be cool though as there’s always also the mono out…
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

On second thought about panorama mod - will try and repurpose the headphones output for that…
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

aaand, panorama mod is indeed possible and not too tricky - I repurposed an smd op-amp but this can be done by putting in another dual opamp on a sub pcb as well - will describe this in nmore detail soon on my webpage, but the gist of it: tap each voice at the output buffer cap, feed into two resistors (one for left, one for right); centre = 11k each, if you want slightly on the side use 12k and 8k5, more extreme pan = something like 15k and 6k8; then wire together all "left" resistors and use summing amp; same for "right" resistors. basically like the preset panning of instruments on a TR909 and similar setups

quick demo of two sounds with mild panning; two voices are centre, the other two slightly left/right
MInilogue_Panoramamod_test2.mp3
(1.27 MiB) Downloaded 6 times
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SphericalSound
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Re: Korg Minilogue Modifications (sound engine)

Post by SphericalSound »

If I were the Korg´s CEO I would be hiring this guy so fast
burgerboy
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Re: Korg Minilogue Modifications (sound engine)

Post by burgerboy »

Maffez wrote: Mon Jul 04, 2022 12:20 pm aaand, panorama mod is indeed possible and not too tricky - I repurposed an smd op-amp but this can be done by putting in another dual opamp on a sub pcb as well - will describe this in nmore detail soon on my webpage, but the gist of it: tap each voice at the output buffer cap, feed into two resistors (one for left, one for right); centre = 11k each, if you want slightly on the side use 12k and 8k5, more extreme pan = something like 15k and 6k8; then wire together all "left" resistors and use summing amp; same for "right" resistors. basically like the preset panning of instruments on a TR909 and similar setups

quick demo of two sounds with mild panning; two voices are centre, the other two slightly left/right

MInilogue_Panoramamod_test2.mp3
I cant keep up with this, this is better than Christmas.

Going back to the filter input gain, would it be possible to control all 4 vcfs gain with one pot? Or would i need a pot per voice. Noob question apologies.
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

ha, jingle bells! :)

For the increased filter input - on my unit I think I keep this as a fixed modification (for now, at least).In moderate amounts a pot would not make that much sense maybe since you can always dial back the VCO levels. If you want this switched, you would indeed need a x4 switch - either electromechanical or as an IC switch (for instance, a 4066).For testing, I have some of these on order and see if they fit nicely under the hood: https://www.musikding.de/Toggleswitch-4PDT


Real variable control might be more interesting if you go to extremes (vca overdrive would be maybe more interesting in this regard). And I'm not sure what would be the best way - there are digipots, for instance, that could be controlled by one CV, but I haven't looked into that.
burgerboy
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Re: Korg Minilogue Modifications (sound engine)

Post by burgerboy »

Maffez wrote: Tue Jul 05, 2022 4:10 am ha, jingle bells! :)

For the increased filter input - on my unit I think I keep this as a fixed modification (for now, at least).In moderate amounts a pot would not make that much sense maybe since you can always dial back the VCO levels. I
Oh durr, yeah that makes sense, im forgetting about the individual vco levels, i dont have a minilogue in front of me, yet.
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

holy guar gum - just finishing up voice-intermodulation modification (VCO1 of one voice xmods and/or ringmods VCO2 of another voice), and this is how you can easily warp a simple sound into something else.... voice panning is active on this one too
Voice_intermods_Demo_1.mp3
(1.71 MiB) Downloaded 4 times
Voice_intermods_XM_RM_andPAN.mp3
(1.04 MiB) Downloaded 4 times
burgerboy
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Re: Korg Minilogue Modifications (sound engine)

Post by burgerboy »

Maffez wrote: Thu Jul 07, 2022 12:55 pm holy guar gum - just finishing up voice-intermodulation modification (VCO1 of one voice xmods and/or ringmods VCO2 of another voice), and this is how you can easily warp a simple sound into something else.... voice panning is active on this one too

Voice_intermods_Demo_1.mp3

Voice_intermods_XM_RM_andPAN.mp3

That sounds amazing, and basically makes the minilogue a completely new synth. From memory my old minilogue was flexible to a point, but this is next level
Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

and some vid-eah - some fun tinkering with that Korg :)

Maffez
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Re: Korg Minilogue Modifications (sound engine)

Post by Maffez »

and a bit of mucking about with the delay chip - ugh, that's a sweet lofi thing in there :)
Delay_long_looper.mp3
(2.27 MiB) Downloaded 4 times
totaldelaymeltdown.mp3
(1.38 MiB) Downloaded 4 times
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