[sdiy] Roland MKS-80 Revision Differences

[Bob Weigel]

1) The slot might be the same as an MKS30's ..I don't know.  I have a 
few scrap ones here. 

2) From my web page which looking I possibly originally got from 
retrosynth though I think it's in my service manual also..

Uncommon chips/modules used: version 80.1 uses CEM3340 vco, IR3R05 VCF. 
80.2 uses IR3R03 VCO and IR3109 VCF and both use BA662 and CEM3360 vca's 
and some others more obscure;

-------- I continue:

So the main sonic difference I'd think  would be the filter followed by 
the VCO. -Bob
cheater cheater wrote:

>Hi guys... I have two MKS80's here...
>
>One has a broken cartridge slot - any idea how much this part could
>cost and where I would get one?
>
>TL;DR: they sound almost the same and the difference is probably going
>to be easy to mod in or even trim in.
>
>There are some sonic differences between them, wonder if you guys can
>come up with where they come from. It might be due to fine-tuning: I
>haven't calibrated the units (yet? - not sure if I want to tune the
>Rev3, it sounds just right, but the Rev4 can definitely use some time
>with me and a screwdriver)
>
>One is Serial No. S00001, a Rev3, the other is an SN491214, a Rev4.
>
>The sound differences might be a bit more than the zone of two units
>of the same model/revision sounding different, but not that much
>overall. The xmod is somewhat different (probably due to calibration
>as the XMOD area seems very much the same electrically), and the
>thing's output distorts in a different way.
>
>They both sound vastly different from the Rev 5 I had a chance of
>using via Richard in Cambridge, who sold me a couple Yamaha SY-2's
>which both sound different from each other as well!
>
>Let's start with the most obvious difference, the DAC:
>
>one has IC10 coded:
>Intersil
>ITS80141
>8311 A
>
>and next to it IC11:
>
>TL081CP
>J333A
>
>and IC12:
>
>IR9022
>544C
>SHARP
>
>The new one has a socket for IC10 into which a board was input:
>
>It has got:
>
>-two small toshiba DIP-10's (narrow body) labeled:
>
>TC40H273P
>8439H
>
>(they have an 'old' Toshiba logo with a pretend-hand-written cursive fontface)
>
>- A part with what seems to be the mitsubishi logo (could be wrong:
>it's a triangle with what seems to be smalle triangles on its
>vertices. it's very fuzzy)
>It is labeled:
>D/A CONVERTER
>MD6205 2510
>
>It's a weird die format that i've never seen before. It has a silicon
>die in the middle, and it's on what I've seen referred to as a
>'hybrid'. That hybrid is a white board and holds the pins. The silicon
>die is a bit smaller than the hybrid and the difference is glued
>together with what looks like gray silicone glue.
>
>The add-on board also has 4 small caps and a small resistor. It has
>wires going off to IC12:
>
>IR9022
>54XA (probably a different lot)
>SHARP
>
>red wire connects to top left pin, blue to bottom right pin, seen with
>text facing the normal way.
>
>IC11 is changed to:
>TL081CP
>J441A (different lot?)
>
>
>Wonder if that's similar to the 'bit depth' upgrade the Jupiter8's
>have seen (and maybe Jupiter 6's? Did they have one?)
>
>--------------
>
>Interesting to note that both have BA662 311 A's in the VCO 1 and 2
>mixers for IC37A-D and IC38A-D respectively except the older unit has
>a BA662 401 A for IC37B. It certainly is factory installed. All
>BA662's are 331 A on the lower slave board.
>
>The VCOs on the old one are all:
>CEM3340
>MOH 2466F-01
>8328
>(with a white dot)
>
>The VCOs on the new one are two kinds:
>CEM 3340
>8431 2468G-01
>(white dot)
>upper board: IC32A, IC32C, IC34A, IC34C
>lower board: IC34D
>
>CEM 3340
>8435 2466G-01
>upper board: IC32B, IC32D, IC34B, IC34D
>lower board: IC32A, IC32B, IC32C, IC32D, IC34A, IC34B, IC34C
>
>
>The old one has the waveform selection chips:
>(motorola logo) MC14052B
>CP  J8416
>for IC36A, IC36B, IC36C, IC36D
>
>The new one has:
>4K4 Y
>HD14052BP
>for what is now labeled as: IC36AB, IC53AB, IC36CD, IC56CD (they're
>the same sockets as the old IC36)
>
>
>(Most) el caps near the hinges are 35V 47 uF 105*C on the older one
>and 50V 1 uF 85*C for the newer one.
>
>Some more differences in the filter part as well:
>The CEM3360's are a different rev, and so is the IR3109.
>
>The IC46 JFET is changed from the old one's
>082DT
>JRC
>3107
>
>to a:
>TL082CP
>J441X
>
>Anyone know what it does? Possibly the voice mixer's makeup stage. The
>new one sounds somewhat cleaner - but then, less beefy - wonder if
>that could be a related thing.. Wonder which of those is electrically
>superior. Maybe the TL082 has a trimpot somewhere that will give it
>more/less distortion...
>
>Oddly enough, one end of a resistor in RESO CV AB in the old one
>didn't make it through the hole, it's soldered to the next resistor's
>leg.
>
>The pcb layout is a bit different in the old one where the new one
>(MKS80 rev4) has an empty spot for C143. It has got some wire patching
>in that place and no silk screen.
>
>The Rev3 slave board has some hotwiring on the underside, and even
>some resistors added here and there. The Rev4 has the same resistors,
>but there's no hotwiring. The wires are stuck onto the board with the
>same gray silicone glue as in the DAC - seems the Roland Corporation
>was very fond of gray glue ???
>
>The rev4 really sounds like it needs some fine-trimming. For example
>one of the voices seems to decay longer than the others..
>
>On both of them, the stand-offs supporting the lower module board are
>broken. On the older one, one of the lower stand-offs has broken off
>where it screws into the part that is welded to the chassis. On the
>newer one two of the things that the lower standoffs go into have
>become unwelded from the chassis (the weld points broke off).
>
>The Rev3 supposedly belonged to James Brown and the Soul Collective,
>as a side-story. Was difficult to get it off the previous owner - had
>to notify the police after he would keep hanging up on me for a week.
>He'd sent it out the same day, but I'm still waiting for the receipt
>so that I can file it on expenses (another case for Scotland Yard?).
>When it warms up it smells of what seems to be vanilla cigars or club
>smoke. Probably not club smoke. Did James Brown smoke vanilla cigars?
>(I might be wrong - never been a smoker - but that's sort of what it
>smells like). Wonder if someone can confirm or deny that little
>factoid about it having belonged to Brown. Either way - not selling
>this one - it sounds real good, no matter who used it before. It
>sounds so good it's allowed to stink of cigars TBH.
>
>They both use the same rack ears, but they're mounted with 3 screws on
>the Rev3 and 4 screws on the Rev4. Wonder of they added a fifth screw
>in the Rev5. Richard, what's your comment?
>The Rev3 has six holes in the chassis actually - no idea why, they
>don't line up with the rack ears.. maybe for mounting the rack ears
>backwards, or something like that.
>
>Cheers
>D.
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