Juno 6 MIDI??

[Jaicen]

Just wondering if anybody here has had any luck with a MIDI interface for the Juno 6.

I've seen a couple of threads discussing DCB, but no actual work seems to have been done.

The Juno i'm looking at looks to have a Ju 60 mainboard in it, probably wouldn't be difficult to add a DCB board, then a MIDI -> DCB converter, but surely there's a better way to just get note on/off via MIDI??

Any ideas?

[reve]

Hey there.

If it really is a Juno 60 mainboard (and it's fully populated!), it has dcb -- all you need to do is wire up a jack.  I don't know how likely that is, though... If not, on the CHD ELEKTROSERVIS site referenced in other posts, they've got a circuit that you can can ostensibly wire directly into the 6's CPU to give it DCB control. 

I'm also a Juno 60 owner & occasional midibox builder that's thought about midifying le ol Juno.  In my mind, Midi to DCB shouldn't be tough.  Midibox should be able to *see* the DCB messages, since they're similar enough to midi... they're both chirping at 31250 baud, right?, so you wouldn't need any external circuitry to convert the speeds. At first it seems easy, because they both go Status byte, Data Byte, right?

Then I stopped to think about voice rotation.  eewwww.  I *think* DCB transmits transmits all the voice voices in each key code block (anyone wanna confirm?).  If that's the case, you couldn't just translate each incoming DCB note as a sysex block and translate it on the fly if you wanted any degree of polyphony.  That makes the project much, much harder for a beginner like me.  Enough to make it a nonstarter, even.

It's still doable, but someone with brains'd have to do it.  Note on/off is all dcb'll do you for on a Juno, btw.  Patch change only works on the Jupiter, IIRC.

[Jaicen]

Was DCB populated on the Juno 60 main voice board? I was under the impression it was on a seperate B board with all the memory associated controls. In that case I guess it is a Juno 6 board (but it does have the 60's Test modes, like unison etc).

Maybe there's a way to graft onto the keyboard matrix, in a similar way to the Polysix retrofit?? Note on-off would be just fine.

[reve]

Was DCB populated on the Juno 60 main voice board? I was under the impression it was on a seperate B board with all the memory associated controls. In that case I guess it is a Juno 6 board (but it does have the 60's Test modes, like unison etc).

Maybe there's a way to graft onto the keyboard matrix, in a similar way to the Polysix retrofit?? Note on-off would be just fine.

Er no, not on the voice board.  On the CPU board.

I broke out the Juno 60 manual this afternoon and did a bit of skimming... and as it turns out there were some DCB issues that I didn't think about.

1. Voice rotation isn't a problem.  CPU'll take care of it.

2. Unlike MIDI, there's (odd) parity bits.

3. Unlike MIDI, there's a 2 bit stop bit.

As far as your grafting idea goes, taking MIDI data, emulating the 6's scanning keyboard & the Roland data structure sounds more like a straight PIC project... I don't think trying to shoehorn it into a midibox project would save you much work at all.

[Jaicen]

Actually, I did some searching and came across the Dtronics DCB to MIDI replacement board. It appears to be a Pic (16F84) that replaces the DCB circuit completely. I'd prefer to homebrew something like that though, especially when that little PIC+PCB costs half as much as the synth itself!