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Synths |
| Last Updated: | |
| KORG 800DV (Maxi-Korg) | |
| MODS - Rear Panel & Sockets, Proper CV/Gate Inputs | |
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| Synth Index | Korg 800DV | 800DV Mods1 | 800DV Mods2 | |
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| | IEC Main Sockets | Additional Sockets | Proper CV/Gate Input | | |
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Synths |
| Last Updated: | |
| KORG 800DV (Maxi-Korg) | |
| MODS - Rear Panel & Sockets, Proper CV/Gate Inputs | |
|
| Synth Index | Korg 800DV | 800DV Mods1 | 800DV Mods2 | |
|
| | IEC Main Sockets | Additional Sockets | Proper CV/Gate Input | | |
| IEC Mains Socket |
| The 800DV came with a little compartment at the back to hold its power cable & power plug. It's quite neat, but it's still a flying lead.... so I added an IEC Mains Socket and removed the original flying lead. The lead compartment is now empty.... |
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I placed the IEC mains socket in the middle because that's quite near to the power supply board. Disaster did happen to me while drilling on the rear panel - the PSU board is directly located behind, and I think i accidentally bent a transistor, and in the end caused it to short out a fuse. I could've removed the PSU board before doing anything to the rear, but hell, you'd then have to remove the top panel , keyboard, the frame holding the front panel, plus a lot of other things before you can remove the PSU board.... the metal frame design of the 800DV made it quite difficult to access anything at the back.... |
| Note: To make the IEC Mains Inlet hole, I use a screwing hand tool, which is an M10 Radius Hand Hole Cutter, 28x21mm (RS Cat.#543-614 or or 541-501), with matching 10A Snap In PCB Mount IEC 320 Plug Socket ( |
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| Sockets |
| As I knew i was gonna add CV/Gate and there are 2 sets (Upper / Lower), plus 4 Aux CV's for the 2 travelers, ie, HPF (Upper) / LPF (Upper), HPF (Lower), LPF (Lower), I actually drilled and made 10 holes for sockets (plus one for MIDI for future use!) |
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| Proper External CV/Gate In | |
| The 800DV CV/Gate
sockets that Analogue Solution provide, would require holding down 1 key
on the keyboard to work. This is actually due to the S&H Gate Circuit of
the 800DV, which needs -V (-10V) at KEY OFF, and Open at KEY ON. If this
voltage change is not given to that part of the circuit, the trigger/gate
will not work. The Japanese
E-Lab site has
all the info and the proper CV/Gate Mods Schematics on the 800DV (site in
Japanese). The circuit/schematic that he provides, also incorporates a CV Tuner, which is very useful! |
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| I used
the OP-07 op-amp instead of having to use a stepdown voltage regulator (as
the 800DV operates at 20V, but most op-amps' max supply voltages are <
15V) and built the circuit on stripboards... I dun do custom made PCBs, so I convert everything into stripboard. It's nice, and everyone without PCB making equipment could do it. |
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Stripboard for SINGLE CV/Gate (Need 2 of
these) |
Combined Stripboard for
Dual CV/Gate |
| Took me a while in getting this to work, because initially, i got one of the transistors pin-out wrong, because the information on a datasheet i found on the web was wrongly labelled... bugger! | |
| A lot of care has to be taken when wiring this up. | |
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One main problem was the
Internal / External CV/Gate switch.
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| I also configured the CV/gate In Jack Sockets to switch between linking Upper/Lower - ie the Upper CV/Gate is wired and routed to the Lower CV/Gate socket until a jack is inserted and breaks this connection. this way, I can use just 1 set of CV/Gate and control both Upper/Lower voices as dual voice but also have the option of plugging in a 2nd CV/Gate if I want split operation. | |
| Mounting | |
| Mounted the board next to the PSU board, just under the CV/Gate In sockets: | |
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Connectors are used, and I have an extra board with just the CV Tuner Trimmers, mounted on top of the REPEAT/RING MOD PCB: |
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| This E-Lab circuit is actually very good - as all the functions like Bender, Portamento, Repeat would work for he external CV/Gate Inputs. | |
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