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Moog Rogue: adding a Filter CV input

The Rogue in its original form includes keyboard CV and Gate inputs and outputs. It’s a slightly odd arrangement of TRS (stereo) jacks – one for the CV, with the input on one terminal and the output on another, plus signal ground, while the Gate connector has an even more awkward arrangement of short-to-ground on one terminal and positive trigger on another, either of which can act as input or output. It’s not great. But it does work, providing you have the right cables.

Rather than split these into separate jacks, which would be a handy mod, I just use custom made cables for my interconnects between CV devices. However, the Rogue lacks a CV input for the filter, which I thought might make a useful addition. It’s a simple enough job.

I decided to use a 3.5mm minijack for the sake of convenience. Pick a spot on the rear panel and drill a suitable hole:

photo showing a newly drilled hole for the Moog Rogue filter CV input modification

Freshly drilled hole for the Filter CV input jack


photo showing a newly drilled hole for the Moog Rogue filter CV input modification (inner)

Inner shot of the Filter CV input jack hole

I had a switched 3.5mm mono socket to hand, so used that:

photo showing the Moog Rogue Filter CV input jack (inner)

New Filter CV input jack (inner)


photo showing the Moog Rogue Filter CV input jack (outer)

The new Filter CV input jack from outside

Solder a ground wire from the appropriate jack terminal to the Rogue’s jack PCB. Its large solder plane is suitable and easy to work with:

photo showing the ground wire of the new Moog Rogue Filter CV input jack

Grounding the Filter CV input jack

The filter CV input requires a 45k3 resistor to give the same scaling as the keyboard. As presented here, there is no onboard scaling, so if you want to run the input as anything other than 100% follow, use an external amplifier/attentuator. It would also be possible to build such a circuit into the Rogue, but I chose not to for simplicity.

photo showing a resistor soldered to the Moog Rogue Filter CV input jack

Solder a 45k3 resistor to the Filter CV input jack

The other end of that blue wire goes to the filter CV node on the main PCB. Rather than outline it on the schematic, I’ll just show you where that is on the board. This is the point where various filter CV inputs are summed. It’s an easy job to solder a wire at the top of this area:

photo showing the Moog Rogue Filter CV summing node

Filter CV summing node

Here’s a wider shot. Note the longer black wire is a previous bodge and not related to these mods and repairs:

photo showing the Moog Rogue Filter CV summing node and input mod wiring

Filter CV summing node and input jack wiring

I used a Dymo labeller to add the finishing touch to the back panel:

photo showing Moog Rogue Filter CV input jack mod

Filter CV input jack mod, finished!

Hey presto! A filter CV input scaled at the same degree as the keyboard. I use a Kenton MIDI-CV interface, which has an auxiliary output for filter CVs, amongst other things, so this little mod should come in quite handy.

Moog Rogue: replacing the power supply

The Rogue’s original power supply is not ideal. It uses an external transformer in a box with one cable going to the mains, and another cable plugging into a 3.5mm headphone-style minijack on the synth. The minijack delivers a nominal 24V AC, which is then rectified into +12 and -12V DC internally. The power switch on the synth simply connects/disconnects the AC input at the jack.

When I received my Rogue, the transformer was damaged. Rather than buy a replacement, I decided to install a power supply inside the body of the Rogue. There is plenty of room to do this safely.

NB: I take no responsibility for anyone’s actions regarding mains electricity. If you are not confident working with it, don’t. Hand the job to someone qualified.

First job was to desolder the power inlet jack, and solder two wires to the place where the jack was on the main PCB. Unfortunately, the photo below is the best I have at hand. Note the two red wires supplying low-voltage AC:

Photo showing replacement power jack wiring

Power minijack replacement wiring

These two wires go to a connector that allows one to plug or unplug from the transformer for ease of maintenance. There are several kinds of connector that would work; I chose the type found in computer power supplies, as it’s what I had in the spares box:

Photo of replacement power supply connector in Moog Rogue

Replacement power supply connector

The other part of this connector goes to the low-voltage AC output of a transformer. The service notes state the Rogue requires 24V AC at 200mA. I leave selection of a suitable transformer up to you. Note that the Rogue’s rectification is provided by a 78M12 and a 79M12. I used a twin-secondary 12V (with the two 12V secondary windings wired in series to give 24V) rated at 12VA – the Rogue is rated at 6W. Again, I am not taking responsibility for the safety of others here, only providing an outline of my own process.

The transformer is bolted to the base plate of the Rogue. An earth lead is connected to one foot of the transformer:

Replacement mains transformer for Moog Rogue

Replacement mains transformer for Moog Rogue

From the transformer’s mains-level connections, wiring goes to a newly-added mains inlet. I chose the clip-in type with an internal switch and fuse. I cut a rectangular hole in the rear of the Rogue, set low down so as not to interfere with the graphics, which also meant trimming a little of the base plate’s rear lip.

New mains inlet for Moog Rogue

New mains inlet for Moog Rogue

Here is an overview of the result, with tape to secure the looser wires:

Overview of replacement power supply for Moog Rogue

Overview of replacement power supply for Moog Rogue

Here is the result from the outside:

Replacement Moog Rogue power inlet

Replacement Moog Rogue power inlet


External view of the screw mounting for the Rogue's replacement transformer

External view of the screw mounting for the Rogue’s replacement transformer

My Rogue also came with a plug to stop up the hole left by removing the power jack:

Photo of the plastic bung used to cover the Moog Rogue's old power inlet jack

Plastic bung to cover the old power inlet

I tend to use the mains switch on the rear, and leave the panel switch set to ON. It would be a simple job to remove and bypass this, but I consider it unnecessary.


EDIT IN RESPONSE TO A COMMENT: I used a 250V/0.25A fast fuse in a built-in fuse holder in the panel-mounted inlet, which is in addition to the fuse in the UK mains plug. This is a higher current rating than necessary, but it was the lowest I had in my parts box at the time. I have seen two other examples using 120V/0.1A and 120V/0.2A respectively. Your choice of fuse depends on your local mains supply voltage, and you should always select a fuse rated for that supply (eg. nominal 240V here in the UK, 120V in the US, etc.). The current rating should allow enough room for the synth to power up and operate without blowing it. The Rogue is rated at 6W, which works out at 250mA at 24VAC. If we translate that to 240VAC, this drops to a mere 25mA. At 120VAC, it would be 50mA. In either case, a 100mA fuse should be OK.

I’m not going to justify what I now consider rather scruffy wiring – suffice to say that I did this mod three years ago, and would take more care over it these days! However, as it stands this mod has never given a moment’s trouble. I’ve since been in and tidied it up a little.

(2nd April ’18)



Moog Rogue: cleaning and repairing the dust shield

Between the top panel and the main PCB, the Rogue employs a sheet that fits around the controls to prevent dust from clogging the sliders and switches. For some reason, the material has a tendency to decay, and after 20 years, it’s likely that it has turned to crumbly black goo. This goo is horrible stuff, and will stick to anything. The only remedy is to scrape it away.

My own Rogue arrived after a clean, so I have no photos of this goo. But below is a picture of the switches collecting dust after using the Rogue with no dust protector for a while. Clearly it would be a good idea to not only remove the sticky residue from a decayed dust-shield, but to replace it so as to avoid having to clean all these contacts.

photo of dusty switches in a Moog Rogue

Dusty switches in a Moog Rogue

The best material I have found for the job is neoprene sheeting. It can be found at craft stores, or online, and comes in sheets around 2mm thick, which is ideal for this purpose. I use black sheets around 200 x 300mm in size, though it doesn’t matter much what size the sheets are because they will be cut into much smaller pieces for application.

If we look at the Rogue’s control panel, we can see a cluster of sliders, two separate sliders, and several switches spread across the surface. It would be possible but awkward to cut one sheet to fit all these holes at once, so I chose to use a simpler method: apply individual pieces to the switches, and use larger pieces for the sliders. The switches being relatively broad, I chose to use snug slip-on pieces over each switch. The sliders only need to poke through a slot, so I chose to attach slit pieces to the panel and have the slider tangs poke through.

photo of the interior of a Moog Rogue control panel

Interior of the Moog Rogue control panel

Measuring the panel is easy enough:

photo of a drawing for a Moog Rogue dust protector

Drawing for a template for a Moog Rogue replacement dust shield

The neoprene sheet can be marked with pencil, and scored and cut with a craft knife:

photo of cutting a replacement neoprene dust sheet for a Moog Rogue

Cutting a replacement neoprene dust sheet for a Moog Rogue

Here are some close-ups of the slider protectors:

photo of replacement neoprene dust sheet for slider bank of a Moog Rogue

Replacement neoprene dust sheet for slider bank of a Moog Rogue

Single slider dust protector cut from neoprene sheet for a Moog Rogue

Single slider dust protector cut from neoprene sheet for a Moog Rogue

Checking that it fits:

photo of neoprene dust sheet for a Moog Rogue

Checking the slider dust sheet fits

Fastening the sheets to the panel is also easy. Rather than glue, I use double-sided sticky tape. These strips are about 5mm wide. I buy broader tape and cut the lengths down the middle. Care should be taken applying these taped pieces to the panel as the adhesive sticks quite readily.

photo of dust sheet with tape attached

Using double-sided tape to secure the dust sheet to the panel

photo of Moog Rogue panel with dust sheet attached

Moog Rogue panel with neoprene dust shields attached

The pieces for the switches are more fiddly. I cut small rectangles and used a regular office hole punch to make the holes for the switch to poke through:

photo of a small piece of neoprene with a hole-punched hole

Using a hole punch to make the switch dust protectors

They happen to fit nicely. In retrospect, I would have used larger pieces, as these were a little narrow for my liking, but they still do the job.

photo of neoprene switch dust protectors in place

Switch dust protector pieces in place

Once the job is complete, the panel looks much neater from outside, and the likelihood of dust getting in to clog the controls and damage them is much lower:

photo of Moog Rogue with replacement dust sheet

Finished! The Moog Rogue with fresh replacement dust protectors installed

Moog Rogue: open wide

Opening the Rogue is easy enough. There are five screws to undo on the base and back, and two on the front. It doesn’t matter what order you work in, as long as care is taken while moving the Rogue when it is only partially screwed together, so as to avoid spraining or cracking the screw points. Four screws are located at the corners of the base plate, as outlined in red on the photo below. One screw is located at the bottom of the rear panel, also outlined in red on the photo. Two screws are located on the front, one at each end of the keyboard. The second photo shows one of these partially undone.

photo of the screw points on the base of a Moog rogue

Moog Rogue screw points on baseplate

photo of screw points on front of Moog Rogue

Moog Rogue screw points on front of keyboard

Turn the Rogue upright and lift the lid. The third photo shows my previously-modified Rogue open like this; note the wiring at the left that connects the keyboard to the upper part. This is present in an unmodified Rogue. Be careful not to strain this.

photo of Moog Rogue open for work

Moog Rogue gut shot

To remove the main PCB from the top part, firstly remove all the knobs from the rotary controls and sliders. They should just pull off with little difficulty. The main PCB is attached to the top section by mean of three screws at the front, and a clip at the rear, which is itself attached to the body via three more screws. It is a simple matter to unscrew these in whichever order you feel works best. The clip simply slides off the PCB. The photos below highlight the locations of these screws from inside and out. Note that in the photos I have also removed the jack PCB. This is attached to the rear panel by the nuts around the jack sockets. Simply unscrew them and the PCB pulls away.

photo of Moog Rogue internal screw points

Moog Rogue internal screw points

photo of the location of Moog Rogue screw points for the main PCB, external

Moog Rogue screw points, main PCB, external

The final photo shows the Rogue open with the main PCB and jack PCB removed from the panel.

photo of a Moog Rogue open with PCBs removed for work

Moog Rogue open, with PCBs removed for work

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