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Roland SH-09 (Midi-fied)
MODS - IEC Mains Plug/Socket, Noise Routing, Filter/Bender Control Switch

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| IEC Mains Socket | Noise Routing | Filter/Bender Control Switch  |

IEC Mains Socket
Problem about the Roland SH-09 is, it has a flying mains lead on the back, but it is coming out at the lower part of the rear panel. Normally I would just cut the wire and put an IEC Mains Inlet Socket there, but in this case, it would mean that the IEC Inlet Plug would then tilt the synth when it is plugged in.
There was only one place in between the ROLAND Logo and the Audio Input socket that you might be able to do something there, but i figured it would be too close when the lid is closed. So the IEC Mains socket has to go on the sides. Good thing is the sides are PLASTIC and easier to drill.

Just - just fit.... 
As for the original hole where the original mains wire came out, I fitted a fuse holder there....

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 (311-8031 or 488-191).



Noise Routing
This mod I got from the elab (Japan) site. At the moment (June 2004), his site is gone and i haven't found where it has moved to... so i'll include most details here.
Since the External Audio has its own Level Fader, when not in used, we can actually route the NOISE signal to this, thus you can have a certain amount of Noise added to the VCO Osc/Sub Osc sound.

Since the External Audio In socket is a switch socket, some PCB track cutting has to be done. Also, we still want to use External Audio Input, so a jack plugged into the socket would disable the Noise and have the External Audio routed into the mixer.
The following diagrams were taken from elab (Japan) site:


(Click to enlarge)

Actual WIRING that needs to be done.

A 10k resistor is used to attenuate to ground.

Also, a 560k resistor is used to balance the Noise signal to avoid clipping. (Since the Audio In has a gain amplification)

So what we need to do 1st is to cut the PCB tracks where the Audio Input is.
First unplug the connector and then remove the screws to all the jack sockets, the Jack Socket PCB will come out. The Audio In Socket is the last one (on the right).

Cut the tracks:

Wire in a 10k resistor and also the re-route ground wire:

On my SH-09, there's a little hole there and I actually have the 560k going thru the hole 9and soldered).

 So now the wire will go to the NOISE output.
Noise Out Location:
The Noise Gen is on the LEFT of the PCB...

Although you can plug the wire to the T P NOISE pin, but this Noise out is slightly Hi-Passed. the proper Noise Out is at the leg of R173 (330k)  - right leg of the top left resistor / above C40 (100P) capacitor.


What i did (wasn't a good move tho)... I drilled a little hole and inserted a pin there and soldered a short wire to the leg of R173 (330k). Well, this is so that i can just use a header plug and plug the signal in...

I should have fins a better place for this, since where i am putting the plug, it will obstruct the TRANSFORMER when the front panel is closed. (In the end I have to bend it down a bit...)


But basically the Noise Re-route Mod is done!


So now.. without anything plugged into the External Audio In socket, the EXT AUDIO slider works as a NOISE BALANCE....




External CV to VCF / BENDER Routing
From the Hyperreal Music Machine site, there is 1 text about routing external AUX CV to BENDER to control VCF.

You see, there is one kool thing about the SH-09.

The Pitch-Bender has 2 sliders above it, governing what the BENDER does.

If the BENDER VCO slider is activated, it, the BENDER will affect the Pitch, and the range is very wide.

If the BENDER VCF slider is activated, BENDER will affect Filter Cutoff - PLUS OR MINUS - Add or subtract.

If both sliders are used, then u get filter and pitch bending at the same time!

Since I a going to add MIDI and my MIDI-to-CV has extra AUX CV, instead of wiring to the VCF directly, why not wire it to the BENDER, so i can control BOTH or either one!
There's a BENDER T P PIN on top of the VOLUME knob. Looking at the schematics, this seems to route to the 2 sliders. However in real life it isn't. AUX CV applied to the T P BENDER PIN would only affect the PITCH...
The point where AUX CV should go to, in fact is input (PIN 3) of the IC19.
  Solder side of the BENDER PCB.

The Grey AUX CV wire is soldered to PIN3 of IC19.


Right, simple. BUT what if you are using the onboard keyboard instead of external Midi-CV? Since the external CV is now applied constantly, it will make the BENDER do sod-all.
So we need an additional On/Off switch (SPST). 

It's actually very simple, as this is just to allow or disallow the AUX CV running into the IC.

So basically ...
OFF = No Aux CV, Internal BENDER Works.
ON  = External AUX CV.


Again, as there's no space on the front panel (as the inner side would obstruct internal wires or the keyboard when closed), I mounted the switch on the Side Panel:


1. The 2 sliders for VCO / VCF still determine the amount of effect affecting the Pitch and Filter Cutoff.  
2. Since the Bender adds + AND - voltage, it would be ideal if the AUX CV can do -5V/0V/+5V.
If not, it will only do ADD. For filter, this would still do, since you can set the initial VCF Cutoff to a lower value and add the AUX CV accordingly.



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