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Synths |
| Last Updated: | |
| Roland SH-09 (Midi-fied) | |
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| MIDI - Internal MIDI-to-CV with additional controller, Midi Switch/Routing | |
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| Synth Index | Roland SH-09 | SH-09 Mods | SH-09 Midi | |
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| | Midi-to-CV | Midi Switch/Routing | Other Stuff/ To Do's | | |
| MIDI-to-CV | |
| CHOICE | |
| I needed some basic MIDI-to-CV Convertor. Constantly buying Doepfer MCV-4 and mounting them inside is not ideal as they are not cheap. | |
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I found that recently
Papareil
Synth Labs starts selling PCBs for his modules, and there are 2
PIC based Midi-to-CV convertors, the
MCV876 and
MCV628. |
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Took about 2 weeks for the boards to arrive after my PayPal
payment. Marc (the developer) has been real nice and emails are very
prompt. |
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| Actually the MCV876 would be more appropriate for this task. But since Marc emailed me saying he's updating the firmware and software to add more features, so i decided i'll use the MCV628 instead (and save the more powerful MCV876 for other projects). | |
| The MCV628 has basic Pitch CV and Gate outs, plus 1 additional Aux CV. | |
| Constructions | |
| The MCV628 construction is pretty
simple: 9 jumper wires, a few resistors and caps, few IC's and the PIC. |
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| It did take me longer than other PCB constructions tho, this is because the holes on the PCB are actually quite small. And some components, like the 7805 regulator, are actually larger, and some drilling has to be done to slightly enlarge the holes. Also, as it is quite a small neat board, some PCB tracks are quite close to each other. Very careful soldering is needed otherwise it would start short circuiting things... | |
| PIC16F628 Programming | |
| I got a USB PIC Programmer which is a
QEL
3128 Micropro PIC Programmer. It's USB, USB powered. You can either buy a kit (UK£24.95) to build this PIC Programmer or buy an assembled one (£39.95) or a complete finished product with the ZIF socket (£54.95). The ZIF socket makes it very easy for inserting / changing PICs... |
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| Simple to use. put the PIC in, launch the software program, load the HEX and program. | |
| Works straight away. | |
| The good thing about the Papareil MCV's, is that, other than the simple Config Switch/Learn Button and Gate On LED, Marc has also written software program for configuring the PIC. | |
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The PICs actually takes MIDI SysEX sent from the config software. You can config the Base Reference MIDI Note, Scale or Note table and also what controllers the AUX CV is using. Pressing the SEND CONFIG button will output Midi SysEx to the board. |
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| Testing | |
| Power ON, LED flashed 3 times, indicating
PIC is booting correctly... Thought I'll send the SysEX from the Config Software (instead of tweaking/calibrating it) and... |
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| Works straight away, even without fine tuning the CV's... (dun even need to turn a trimmer!) | |
| SH-09 GATE (+15V V-Trig) | |
| One thing tho... | |
| The older SH-series actually use +15V V-Trig GATE. The MCV's output +5V GATE. | |
| So there's a need to do get the GATE going at +15V. | |
| On elab (Japan) site, he had this gate pull-up circuits for his SH-2000 and SH-3A. Since the SH-09 is very similar, i thought I'd try this out... | |
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The circuit is basically an Op-amp pulling up the GATE from +5V to +15V |
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I did this on a small stripboard, basically and LF356 single Op-Amp and 3 resistors. (Click on the images to enlarge) |
| Mounting | |
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Mounted the MCV628 in the spare space on the keyboard side, between the PSU PCB and the transformer. The SH-09 has many pre-drilled holes on the base, so it is a synch - just insert a screw and nut! Note: Power (+15V/0V/-15V) is taken from
the Power Supply PCB at the right hand side. |
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The Gate Pull-Up is mounted on the corner of the MCV62 board! |
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| MIDI In Socket, Learn Switch & LED Mounting | |
| Again, since mounting anything on the rear panel would obstruct things when it is closed. So the MIDI In socket, MIDI LEARN Switch and the Gate ON LED are all mounted on the left side panel. | |
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| NOTE: I should note here that at the moment of writing, the MCV628 doesn't support Pitch-Bend. I've emailed Marc and request if he can add this to the next revision firmware.... |
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| MIDI Switch / Routing | |
| PLANNING | |
| A few planning needs to be done on how the MIDI-CV is used and how it is to be wired to the SH-09. | |
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| On the SH-09 Socket PCB Schematics, we can see that the Keyboard CV/GATE goes to the CV/Gate OUT sockets, which is also routed to the SWITCHED SOCKETS of the CV/Gate INPUTS. | |
| So there are a few ways to put the MIDI CV/GATE. A Switch is definitely needed to switch between Internal Keyboard CV/Gate or MIDI CV/Gate. | |
| This can be either at Pads 9/8 or Pads 6/7. | |
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I decided to do it at Pads 9/8. This way, the CV/GATE OUTs can function as outputs from the MIDI-CV. |
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SWITCH |
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| A DPDT Switch is needed.
Just need to disconnect the connection at Pad 9 and PAD 8 and re-route them to the switch.
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| MOUNTING | |
| I actually mounted a bus header on a small piece of stripboard on the sockets PCB. This way, i can still disconnect the connector so that the top panel part can be totally separated from keyboard part. | |
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PADs 9 & 8 are clearly labelled on the PCB at the right... |
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Switch on front panel, again mounted to the left side panel: |
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| Other Stuff / To Do's |
| FEEDBACK |
| Since there's a PHONE Socket, it is very tempting to put a jack there and route it to the EXT AUDIO IN to get feedbacks... (Try it, the effect can be wild!) This can make the VCF go mad and distort (since the Audio In has quit a high gain amp!)! |
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I could have added another switch to switch between Noise and Feedback... but for the moment, i think that's enough. I can live with placing a jack patchcord at the back... |
| To Do's |
| I may change the MIDI-to-CV to the MCV876 V2. Now this new version has a Midi Clock Sync out on one of the additional Gate Outputs. This can be used, maybe, to drive the LFO clock, so to provide LFO Clock synced to Midi clock. |
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I did find an SH-09 LFO/S&H CLONE circuit on the web, comparing to the original schematics, it does seem there is a point where external CLOCK IN can be inserted. |
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Analogue Solution site has 2 modifications for the SH-09 - 1. BASIC (£17.63 Kit) - VCF, PWM CV ins 2. MODULAR (£68.15 Kit) - VCF, PWM, SH clock, SH signal CV ins. - LFOx3, EG, EG-ve, SH CV outs. - VCA audio in. VCF audio out. So
there are actually lots more one could do with modding the SH-09. |
| Still wanting to rackmount this instead of having it as
this old rusty thing.... Seems like it might have to be a 2u, maybe... |
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As of June 14, 2004. |
