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| Moog MG-1 | Moog MG-1 Mods & Midi |
 Moog Realistic Concertmate MG-1 Mods & MIDI
| Foam Removal | Sliders & Switches | Sockets | VCF IN | VCF CV | MIDI | Other Mods |



MODs and Work on the MG-1
bulletGeneral Works - FOAM removing, New Sliders/Switches, Audio Sockets
bulletFilter Mods - External Audio In to VCF, VCF CV Input
bulletMIDI - Midi-fying the MG-1
bulletOther Mods - Modular outputs and Multi Trigger / Trigger Speed





All MG-1 suffers from one big issue - the black foam paddings that they use under the front panel actually decomposed over the years.

You won't noticed it when you opened the synth, but when you take the PCB out, you'll see all those black foam, sticky and they fall apart if u touch them!

The decomposed foam is very sticky and horrible, so imagine that going into the sliders and switches...

Took me a while to clean them out.

Other MG-1 users have the same issue, see Planet Zero's MG-1 page...
It seems that some of these foam has got into a few sliders and switches, and the sliders are starting to get cracks and so on....

NEW Sliders and Switches

Well, thank goodness, people have made new sets of these MG-1 Sliders and Switches and selling them on eBay. I got a set, and basically de-soldered most of the sliders and switches and re-solder these ... and now they're like brand new.


Since the MG-1 comes with RCA sockets, I added normal 1/4" jack sockets, one for normal Audio Out, and one for Audio In (to VCF). Some people remove the whole RCA board and put the jack sockets there, but i did this quite earlier on, and i actually drilled 2 holes next to the RCA Sockets...

The Audio OUT socket can be wired to the RCA socket PCB. See the RED wire....

The GROUND is basically where that Yellow/Green striped wire goes to, on the above image, you can see I have wired a black wire there near the bottom right of the RCA board....
Wire the ground to both the sockets.
More on the Audio Input Socket below....




EXTERNAL Audio Input to VCF

Well, we have the extra Audio IN socket, external audio can be fed into the socket and goes straight to the MIXER input so it can pass into the VCF section.
There have been lots of debate on this - some say, you should wire a resistor in between, some say a capacitor. On mine, i just wired it direct...

Basically the AUDIO IN should goes to -ve side of C14, near the Source Tone1 and 2 slider.

If you look at it from the back of the PCB, it's the where the pink/purple circle is on this image:

You can just solder a wire from the jack socket to this solder point, and don't even need to take the PCB out.

But since i was cleaning the FOAM and changing the sliders/switches anyway, so i actually soldered it to the leg of C14 on the component side of the PCB...


This is not difficult at all. The CUTOFF FREQ Slider is where you need to look at.
Solder a CV wire to the centre of the slider and now you can apply external CV to control the filter!

See the BLUE wire in this pic....




MIDI-to-CV on the MG-1

I chose the PIC Midi-to-CV again from Papareil Synth Labs.
The MCV628 was used, as in my midified Roland SH-09.

- cheap/cost effective
- Custom PCB
- MCV628 is the basic version, which offers Midi to CV/Gate + one additional AUX CV
- has handy software config program

The MCV628 construction is pretty simple:
9 jumper wires, a few resistors and caps, few IC's and the PIC.

My 2nd time building one of these, i have pre-drilled/enlarge some of the holes on the PCB so that components can be fitted easier to the PCB.

PIC16F628 Programming

I use a USB PIC Programmer -
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...

Simple to use. put the PIC in, launch the software program, load the HEX and program.

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.

One thing tho, maybe because the MG-1's keyboard stats at F, it seems that the base note of the CV IN starts at F (rather than C).

So, on the MCV628 Config, i set the Reference note to Midi Note #41 (F1), and all tuning are then correct.

The Aux CV will then control the Filter CV.

V-Trig to S-Trig
Although the MCV628 can provide -ve triggers (using different firmware of the PIC), but this is not what the MG-1 needs. The MG-1 needs S-Trig, but the MCV-628 outputs V-Trig.

So we need V-Trig to S-Trig conversion.

This is very simple, just need an NPN Transistor and a 10k resistor.

Don't need to do this on a stripboard/veroboard - the resistor and transistor can just be soldered to the GATE wires.


MG-1 has +12V, -15V, 0V and -12V. i used +12V/0V/-15V for powering the MCV628.
These can either be tapped from the PSU board or from the main PCB.
PAD 1 has +12V
PAD 3 provides -15V
PAD 4 or PAD 7 provides the 0V / Ground.

Mounted on the side....

Panel Mounting and Switches...
I mounted the MIDI LED, MIDI Learn Switch on the front LEFT side cheeks. It's plastic, so easy to drill.

Well, I actually added 2 switches.
- One to switch between the internal keyboard CV/Gate and the MIDI CV/Gate.
(Gate from the Keyboard will still be active tho)
- To switch the VCF CV on/Off.



So now, my External CV/Gate still function but the GATE now accepts V-Trig.
I mounted MIDI IN socket near the Power Switch...




There are a few other mods that can be done on the MG-1, but i haven't done them.

Analogue Solutions offers MODULAR UPGRADE Outputs on the MG-1 for £38 (ex-VAT).

This include a VCF CV IN and separate outputs of the VCO's, noise, Bell and Polyphony.


Well, VCF CV IN i've already done.
The other separate outs - i think these can be simply tapped from the sliders on the MIXER section.
Hyperreal Music Machine page has some text files - by Ricard Wolf
- one mod on Multi Trigger (Re-Trigger / Continuous Glide)
- one mod on Trigger Speed Enhance
I have actually done some stripboard drawing for the Multi-Trigger mod, but i haven't actually done the mod yet, maybe I'll add these one day....






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