Why do the PWM knobs only go up to 95% ?

PS-20 is an ultra-realistic, polyphonic, hot-rodded tribute to Korg's renowned MS-20.
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Ian Craig
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Why do the PWM knobs only go up to 95% ?

Post by Ian Craig »

Hello,

back in 1984 I had a sound on my Korg MS-10, demonstrated here on this edit from a tidied up cassette.
It starts with the sound in question and then has another layer over the top of it
Korg MS-10 Pulse Width Modulation achieved by patching the Modulation Generator's shape output into the PWM input socket and turn the PWM knob as far right as possible i.e. 100% (which, without the PWM meant an external signal could be patched in and the synths filters etc applied to the external sound without any synth sound mixed in, which is handy for guitar).
However I found a much more brutal use for it, here by modulating the Pulse Width it created a brutal Doctor WHo theme type sound.
Unfortunately, I cannot replicate this with the PS-20 as the Pulse width is limited to 95%, please rectify this and enable me to use this sound again. Thanks
https://iancraig1.bandcamp.com/track/cl ... ion-1-1984
Last edited by Ian Craig on Fri May 28, 2021 11:04 pm, edited 1 time in total.
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cherryaudio Greg
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Re: Why do the PWM knobs only go up to 95% ?

Post by cherryaudio Greg »

Hi,

This isn’t an exact emulation of the hardware, but the designer did get that value range from the vintage MS-10 he owns. When we design these synths, we’re paying close attention to actual hardware.

Greg
Ian Craig
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Re: Why do the PWM knobs only go up to 95% ?

Post by Ian Craig »

Yes, well, it does need the actual 100% range that I had on my hardware (that I stupidly lent to my brother to get some space) that can be heard on the clip. If his can replicate that pulse folding effect, I have to say that after a week of trying I cannot.... Besides it was my suggestion that he followed in making it into an instrument rather than just a collection of Voltage Modular modules, which I am grateful about, but it does need that tweak.
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cherryMitch
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Re: Why do the PWM knobs only go up to 95% ?

Post by cherryMitch »

Hi there... not sure what the PW range is for an MS-10; at the risk of stating the obvious, PS-20 isn't an emulation of the MS-10. As Greg mentioned, the PW range was modeled to be exactly as it is on my vintage MS-20 (between us at the company, we had two new ones and two old ones, and mine sounded the best, so we used it as the "standard"). Given that these are wonky old analog synths, it's possible that the exact PW limits on different units varies, but I believe mine was fully serviced before I acquired it - everything works flawlessly on it, so I have no reason to believe anything is out of whack.

Interesting related side note (and how you know we're really paying attention to this stuff): When we were working on PS-20, the 50% square PW setting never sounded right; my MS always sounded more honky and blatty (in a better kind of way). We finally figured out that it was because "50%" wasn't really 50%, it was about 51%. You wouldn't think that would make much difference, but it made ALL the difference for it to sound right, so the 50% PW setting on PS-20 is actually around 51%.
Ian Craig
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Re: Why do the PWM knobs only go up to 95% ?

Post by Ian Craig »

Yes, I thought it was an MS-20 you had, not an MS-10 as Greg stated. Just please open the Pulse Width up to 100% on an update. I don't why such great sonic possibilities should be lost as my MS-10 had from 1983 onwards (so it didn't need servicing.
I screen grabbed the first few bars -
MS-10 single oscillator split into 2 notes by the modulation generator square wave patched into the oscillator's frequency while the saw/triangle/ramp control is patched into the PWM socket with the Pulse Width is set to 100%. Note that the note split in two by the square wave, played by two different keys (a minor third apart) consecutively, is producing a lot more than 4 notes. The sound here has no other effects added to it, it is pure MS-10 recorded to cassette in 1984 (tidied up with noise reduction).
https://youtu.be/27dwDvohY98
It's just a wasted opportunity.
Anyway, take care
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Ian Craig
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Re: Why do the PWM knobs only go up to 95% ?

Post by Ian Craig »

It turns out that I had been running the 32 bit version of Korg's MS-20 for compatability reasons. When I updated the installations for 64 bit only usage I found that everything I needed for that sound was in their 64 bit version. So, it's all good. I forgot to post this at the start of June. My love of this synth was from my own historical perspective, I have no issue with CherryAudio's approach. You guys are producing great things at really good prices and I happily endorse that, don't think I don't. The only issue I have with the implementation is the need for a final stage EQ to tweak the settings (which could be under a little flap, like Arturia use to hide extra settings on the OB-Xa etc). This is because I notice a difference in the sounds between the factory sounds and their software emulations in the recent video for the Memory Mode which could be sorted by a final stage EQ i.e. the balance between the upper mids and the other parts of the sound is different and probably other things too). Anyway, it just a feature request that you can impliment or not, so carry on in any case 8-)
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