Moog Minimoog Model D

[Picture of the Moog Minimoog Model D synthesiser]

A lot has been writthen about the Minimoog, and with good reason, so there's really not much to be said which hasn't already been. After all, it was used by many in the 70's and has a distinct sound which people tend to rave on about. The Moog filter has been cloned by practically everyone under the sun and is one of those "must have" modules. Yes, I have one in my modular.

So, after owning the DSI Mopho Keyboard for a while, and really liking the convenience of an all-in-one performance synth, I decided I would also like something with a more 'immediate' user interface. As lovely as the Mopho is, not all parameters are simultaneously available via the knobs - eg. it uses the same set of knobs to control the oscillators, either individually or both at the same time.

Aaah, the things one does to justify another purchase...

After some internet searches to see what was available, and the general cost of such goodies, I found myself on YouTube watching demo after demo of the Minimoog Model D. Soon after, I was checking out prices on eBay and found that they go for not much more than a new Minimoog Voyager. The unfortunate thing was that they were all in the USA and shipping to Australia would be rather expensive, plus I'd be hit with import duties.


Just when I thought one would be unobtainable, one showed up for sale within Australia with a Kenton MIDI to CV converter box. It had a "Buy it now" price considerably less than if I got it shipped from the USA.


I felt simultaneously excited and queasy - excited because of what I got and queasy due to the money spent. It's an odd feeling. I got in touch with the seller, worked out payment and shipping costs, and then he emailed me after he did the final test before packing. Oscillator 3 was no longer working and it would be a while before his tech had time to look at it. I opted to take it as is and fix it myself.

Days later a huge box arrives at my doorstep and it weighs a ton. I unpack it and marvel at the size of it as it looks much larger than what it does in pictures. Considering the size of the modular systems that came before it, it is mini but not by todays standards. I was pleased to find, as I suspected, that it's a relatively early model - serial# T2401E. I opened it up and was extremely happy that it had its original oscillators. I noticed that the CA3046 chips were socketed so I decided if replacing either of them would bring the third oscillator back to life. Indeed, it did. According to the sticker inside, my Minimoog was made in April and May 1973.

How does it sound? Massive! Although my modular and Mopho surpass it in flexibility, the Minimoog has a rawness and presence to it that can't be explained. It does have a couple of quirks which I will not change:

No dead band in the centre position of the pitch wheel - Any slight movement causes a change in pitch. I use this to my advantage in adding vibrato to notes.
Slight intermodulation distortion when mixing two or more signals - Moog published a modification to fix this. I just happen to like the way it sounds as is.
No octave buffer board - Moog offered this as a factory modification in order to improve pitch stability when switching octaves. Mine seems to be fine without it.

I've replaced all the electrolytic capacitors, keyboard bushings, and the power indicator neon. The 2-pin jones socket for the S-Trig input had already been replaced with a 1/4" socket, so I installed a small converter to accept a positive voltage gate instead. I also replaced the oscillator trimpots with Bourns multiturn cermets as the original ones really really sucked and made calibration a monumental task. Thermally coupling the tempco resistors on the oscillator board to the transistor arrays was another modification I performed and that improved pitch stability. The only other modifications I will do is replace the glide and decay foot-pedal sockets with switches to individually hard sync oscillators 2 and 3 to oscillator 1. As this doesn't require drilling, it's easily reversible.

More photos can be found in my Flickr gallery.