Roland JP-6 "resonance hacks", MKS-80?

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alex_mauer
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Roland JP-6 "resonance hacks", MKS-80?

Post by alex_mauer » Sun Nov 01, 2015 8:57 pm

I just picked up an MKS-80 rev.4 for the lowest amount I've seen in a decade (probably has something to do with all the new stuff out like the Prophet-6) I've owned an MKS-80 before, and a JP-8 at a different time. The resonant character between the two is super different, as most people already know. I came across this JP-6 resonance hack information (with sound examples) a while ago and wondered if anyone has ever tried anything like that on an MKS-80: http://roland-jupiter.org/viewtopic.php ... b&start=15

I like the MKS-80 for what it does. I think it does a better job at unison sounds than the JP-8 too. I am curious if I can get "that resonance sound" with the MKS-80, which I think would make it a way more interesting synth. It looks like the things that enhance the JP-6 in this example are the filters are calibrated differently, and there are resistors connecting VCF to VCA for gain compensation. I kinda wonder if there's a way to actually get the filter chip to behave the way it does in the JP-8 by adding something between the chip itself and the PCB. Seems like there'd be a nice niche market for such a mod, and cost way less than the price difference between an MKS-80 and JP-8. Most synth mods I've seen don't touch the tone and only add OS features. My idea could be the equivalent of replacement pickups for an electric guitar. I'm not super technical, so I don't know if this is even possible. What do you guys think?

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Re: Roland JP-6 "resonance hacks", MKS-80?

Post by mima85 » Mon Nov 02, 2015 10:24 pm

Hi, from what I know the MKS 80 voice boards until the rev. 4 (rev. 5 uses different filters and maybe even different oscillators), are very similar to the Jupiter 6 ones, so the resonance mods probably could be done also on your synth.

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Re: Roland JP-6 "resonance hacks", MKS-80?

Post by alex_mauer » Tue Nov 03, 2015 6:53 pm

Hey you're the resonance hack guy aren't you. Yeah I was very curious if anyone already attempted something on the MKS-80 rev.4. I think... I don't really want my MKS-80 to be the first guinea pig ;)

I thought... it'd be interesting if there was a little pcb that could be installed between the filter chip and voice board which could contain whatever is necessary to make the MKS filter behave like the JP-8... since from what I read it's the same chip but with different surrounding circuitry. It'd be a loss on the JP-6 since the filter design revolves around multi-mode... but on the MKS, it's stuck as a 4pole LPF. I'm guessing by the lack of replies I got on this, no one else cares... so it likely will never happen. I may ask some of my more technical friends if it'd even be possible.

I've found there are other ways of improving the end result with synths that have thin resonance... When I had a Prophet-5 rev.3, I wasn't really content with how the middle of the resonance dial was sort of a dead space... but running it thru an exciter seemed to completely compensate for what was missing.

I think most people's thought is "if you dont like the MKS-80 as it is, just get something else"... but the thing is i DO like it, and I also like the JP-8's take on resonance much more. Ideally if we were all rich we'd all have our JP-8's and MKS-80's ;P

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Re: Roland JP-6 "resonance hacks", MKS-80?

Post by mima85 » Fri Nov 06, 2015 3:36 pm

alex_mauer wrote:Hey you're the resonance hack guy aren't you.
Yes I am :D

To be correct, the entire resonance hack is made up of two distinct mods, one is the custom synth calibration, which is an experiment of myself. The other one is the resonance CV injection into the VCA CV by means of a resistor (or, in my version, with a pair of resistors wired in parallel), which comes from Florian Anwander (it's the 3rd modification in that page). And it's his mod which primarily addresses the issue, mine are just improvements around it.
alex_mauer wrote:I thought... it'd be interesting if there was a little pcb that could be installed between the filter chip and voice board which could contain whatever is necessary to make the MKS filter behave like the JP-8... since from what I read it's the same chip but with different surrounding circuitry.
The IR3109 it's not the filter itself, it's just an OTA. Take for example this image: the filter is made up from the IR3109 AND the array of 4 RC networks connected to the IC outputs, which are external to the chip. So the IR3109 is just a part of the whole filter circuit. This explains why the Jupiter 6/MKS-80 filter sounds different from the one found in Jupiter 8, which sounds different from the one found in Junos, etc... although they all use the same IR3109 chip.

I don't think that just a little board between the oscillators and the filter solves the problem, because you have to exclude ALL the MKS filter circuitry and run the signal thru the customized board instead of the original filter.

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Re: Roland JP-6 "resonance hacks", MKS-80?

Post by alex_mauer » Fri Nov 06, 2015 4:41 pm

Ah, thanks for that take on it. Well, the MKS is its own thing... I was just wondering what the possibilities were. Perhaps a more feasible MOD would be to get the JP-6 filter modes... Get someone to write a new OS that combines the JP-6 and MKS-80 functionalities... or just don't do anything. Anyone want to hire me to come up with a bunch of crazy ideas? ;)

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Re: Roland JP-6 "resonance hacks", MKS-80?

Post by gwpt » Wed Oct 02, 2019 9:09 am

Hi Alex,
I realise this is an old thread but I really like the idea of this mod. Did you ever get anywhere with it?

It doesn’t sound particularly hard (I’ve done the vecoven pwm mod to my mks70 (http://www.vecoven.com/superjx/superjx.html) so I would think this is considerably easier)
Not sure about how to do the mentioned calibration process. Would need more info on that
Anyway, if your still interested perhaps we could look into making it happen

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