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bassmosphere
Joined: Sep 19, 2008
Posts: 17
Location: The Moon
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 Posted: Thu Oct 16, 2008 7:03 pm Post subject:
 MKS-10 Service Notes Available
Subject description: I have the MKS-10 Service Notes! |
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I didn't see this anywhere on the net, so I bought myself a copy. If anyone is interested I will scan it and post it some where. Might take me a while though.
The MKS-10 is a nice sounding analog piano module, which apparently shares some ICs with other Roland synths, IR3019 VCF ro instance . There is some adjustability to the sound, but not much.
It'd be nice to have some more control over the filter(s) and chorus effect, which uses a BBD chip and sounds pretty good. |
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MusicMan11712
Joined: Aug 08, 2009
Posts: 548
Location: Upstate New York USA
Audio files: 151
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| Posted: Sat Aug 08, 2009 12:40 pm Post subject:
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Did you ever scan this? I have had an MKS-10 for years. I can't remember the last time I used it--other than testing it to see if it works. (It did.) Yesterday I looked under to hood and began to wonder if some additional controls can be added. I searched for the service manual and saw your post. Thanks.
Steve |
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stevenclements
Joined: Nov 16, 2005
Posts: 73
Location: Edmonton, Alberta
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MusicMan11712
Joined: Aug 08, 2009
Posts: 548
Location: Upstate New York USA
Audio files: 151
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| Posted: Thu Aug 23, 2012 1:48 pm Post subject:
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Great news, albeit 3 years after a few of us were looking for it: The MKS-10 service notes are now available online at a new site: http://www.synfo.nl/pages/servicemanuals.html . (As for me, 2 years ago I gave up and paid approx. $25.00 for a paper copy.  )
Steve |
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MusicMan11712
Joined: Aug 08, 2009
Posts: 548
Location: Upstate New York USA
Audio files: 151
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| Posted: Thu Dec 27, 2012 12:10 pm Post subject:
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The MKS-10 came up in chat today. I dug out a text file with three tidbits taken from the internet several years ago when I was researching the components and architecture for possible modifications. The first one seems to no longer be available.
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| Quote: | http://donslepian.com/Mirage.html
BY THE WAY The Roland MKS-10 "Planet P" electric piano MIDI Module, a long forgotten product, can be modified to achieve 16 voice location modulation. Seperate outputs for each of the 16 voices can be found on pin 12 of each of the sixteen IR3109 IC's on the top motherboard. Just find audio ground and you're in like Flynn. |
| Quote: | http://dropmix.xs4all.nl/pipermail/synth-diy/2008-October/010320.html
The IR3109 is simply four OTAs and their buffers with a common expo driver. In the JP4 and JP8 Roland simply wired them as four cascaded low pass elements with feedback wrapped around from the fourth stage to the input. The JP-8 has a tap at the second stage for the -12dB output. In JP6 they are wired as two SVFs in cascade - and consequently sound rather different but give HPF and BPF responses.
As we have heard the JP-8's HPF was from a simple BA662 OTA wired as a single pole high pass filter and fitted before the main four pole VCF. Since its not actually tracking the VCOs it has little more effect than a single high pass element in the final output stage of the whole synth. Which is what they did in the Juno-6 et al.
HPF modes can be obtained from cascaded low pass elements in a 'derived' fashion. This is where the various taps are mixed together to form the common filter responses. But to get HPF you need to have the input signal of the filter so that it can be subtracted from the stage outputs. There's a nice section in Electronotes about this - can't remember the number off hand.
But see the Oberheim Xpander for the way they did with the CEM chip. Note that Oberheim used the CEM chip to also mix the two VCO inputs using the CEM's two internal VCAs. Since the internal connection from the VCAs to the first OTA stage is not made available as an output in they had no direct tap to the input of the four stage filter. In high pass mode you need to have this so what they did was to turn the first stage into a buffer stage - this way the first stage tap was actually the input signal to the following three stages. The way they turned the first stage into a buffer is quite clever. Its still a low pass filter, but by changing the timing cap to a very low value, they made the cut-off so high in that stage alone as to make it behave as simple voltage follower. You only get a maximum of a -18dB/oct HP function since you only have three active integrators.
Tony
www.oakleysound.com |
| Quote: | http://www.joness.com/gr300/GR-700.htm
If you are familiar with the eighties Roland synthesizers, then you have likely heard about the dreaded 80017a VCF/VCA chip failure issue. Many synthesizers built by Roland in this period used the 80017a chip: the Juno 106, MKS-30, HS-60 and of course the GR-700. The 80017a is basically a voltage-controlled filter and a voltage-controller amplifier on a single, customized chip made for Roland. The actual components in the 80017a were found as individual elements in the earlier Juno 60 synthesizer: an IR3109 and two BA662 chips. The IR3109 was also used as the heart of the excellent -24 dB low-pass filter in the Roland GR-300. |
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