Moog Music Forum

filtered wrote:is the Opus 3 not a contender in the polyphony discussion? just curious, since it never seems to be brought up when discussing polyphonic Moogs...

My friend had one back in the eighties, but it's too far back in my memory. All I remember is that it sounded good (as all Moogs do) but not much else...

filtered wrote:is the Opus 3 not a contender in the polyphony discussion? just curious, since it never seems to be brought up when discussing polyphonic Moogs...

The Opus 3 is very much like the Polymoog and MG-1 in that it uses divide down circuitry to create polyphony. Divide down chips are getting very rare these days, and I don't see the demand for divide down synths, or string synths for that matter, being all that great.

Some clarification...

Divide down chips can be broken into a few camps:
Simple dividers, the simplest being flip-flop chips (commonly available)
Counters (commonly available)
Top octave generators (rarer)

Today, top octave generators are rare as original replacements.
However performing top octave generation isn't terribly hard to do using a CPU.
Instruments like the Polymoog and Opus had no CPU inside and relied on discrete chips to perform their magic.
But if someone wanted to make a polyphonic instrument today, CPUs have more than enough horsepower to generate every note on a keyboard simultaneously.

Much of the reason top octave generated/divide down instruments aren't terribly popular today isn't so much the unavailability of the chips, but rather that every note is phase locked to every other one.
That is, they're not so desirable.
For example, if one holds down a C note on a divide down instrument and plays another C note elsewhere on the keyboard, there is no phasing or rolling to the sound.
The two notes don't sound all that much richer together as there is no detuning possible between them.
It's the same reason why instruments featuring sub-octaves usually don't sound as rich as instruments that feature two discrete oscillators.

So it's not so much that they're rare.
There are simply easier and cheaper ways today to generate the notes and at the same time, sound richer when played together.
The reason TOG chips are rare today is a lack of demand.
"Supply and demand" is the rule behind the situation.

Kevin, out of curiosity, which chips did the Opus 3 use?

This is off the top of my head, but I believe it was a standard 50240 TOG (same as M083) and either 5523 dividers or TDA1008's.

Interesting. Thanks for that, Kevin.

I looked it up- M083 and TDA1008s.
The TDAs are both dividers and keyboard interface chips (keyers.)
They reduce the parts count and current consumption and are common to find in organs and string synths (like Arps.)

Kevin Lightner wrote:I looked it up- M083 and TDA1008s.
The TDAs are both dividers and keyboard interface chips (keyers.)
They reduce the parts count and current consumption and are common to find in organs and string synths (like Arps.)

Only you could look something up and find that it's the same info from the top of your head. Very cool!

I like the Zep vid better than my memory, I had completely forgotton about that song.
It was one of my favs in jr high.
Nice job on that intro, I can imagine the ascending minor scale starting.

Opus3 isn't usually brought up alongside other polyphonic Moogs because, well it isn't quite a polyphonic synth in the traditional sense. It has three sections: brass, organ, and strings. Apart from a low pass filter on the brass section, a set of drawbars on the organ section, and a chorus on the string section, there aren't a whole lot of parameters available for tweaking. It's a great sounding synth, but it generally doesn't have that very classic and expected polysynth sound. That is to say it does what it does very well, but it doesn't do what most other polysynths do.

The Moog Opus 3 is, in reality, paraphonic. Meaning that it offers only one global filter and one global VCA.

BTW, the Moog Polymoog that came before it was also paraphonic. And parts of its circuits designs were later re-used in the Opus 3 , and MG-1.

The only truly polyphonic Moog in every sense of the term was and still is to this day, over 30 years later, the Memorymoog.

jp8,
a6
omega8

sunny pedaal wrote:jp8,
a6
omega8

What is your point exactly ? I didn't say "the only analog polyphonic synth". I said "the only Moog truly polyphonic synth"...

sorry , i read" the only true analog polysynth"
so i gave my opinion about, what i would like to see under the mini.
i also thought of the opus ( very nice synth/string ), and even the jd800 and neuron for their pad capacities

I thought so...

This is a list of analog polysynths that would, in my very humble opinion, fit very well under my Mini :

Memorymoog
Prophet 5
OBXa
Jupiter 8
CS80
Andromeda A6