Roland JD-990 in box w/manual SN ZE71170

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"One of Roland's high marks of the early 90s, the flagship rack mount beast: the JD-990.

There's a reason it was praised then (and still is now), for many still surpassing Roland's subsequent flagship which came out two years later, the JV-1080. The "JD-990 was soundwise [a] class above [the]1080", as Don Solaris put it.
And don't mistake this puppy as simply a rack version of the JD-900. It's far more than that. Read the additions/ differences itemized further below...

Now, as mentioned above, here's the list of additions the JD-990 has over the JD-800:

Wave ROM was expanded to 6MB (vs 4MB on JD-800) with 195 PCM waveforms (vs 108 on JD-800).

Pan inside each Tone was added. On the JD-800 you can NOT pan individual tone for wide stereo sounds.

Matrix modulation was added on the JD-990. Let’s explain this – on JD-800 you can’t: increase cutoff point of Tone 1, decrease cutoff of Tone 2, increase resonance of Tone 3, decrease pitch of Tone 4 – all at the same time by moving the modulation wheel.

Multiple sources for the same destination added. On JD-990 you can for example use two different LFOs for the same destination – i.e. pitch, filter, TVA. This can create complex modulations. On JD-800 you can only use one source for the same destination.

SR-JV expansion card support. Next to standard JD-800 series card slots, there is additional card slot to use a 8MB expansion boards from SR-JV series. (i.e. Vintage Expansion, Orchestral, SFX, etc.)

Roland JV-80 patch import.

The LFO section has additional waveforms: sine, trapezoid and chaos.

Osc Sync function was added. It lets you synchronise two oscillators – a feature found in many analogue synthesisers.

FXM was added (Frequency Cross Modulation) – again found in some analogue synthesisers. It has 8 positions (labelled Color) that actually control the frequency of the modulating signal, and a depth setting 0 – 100 that controls the amplitude of the modulating signal.

Ring Modulation, for creating all kind of metallic percussion and strange effects.

This synth features 6 types of ”structures” which among many other things let you stack two filters in series, for building complex filter textures.

24 dB filter (using structures), next to standard 12 dB which is always available.

Outputs increased to 8 total.

Polyphonic portamento.

Tempo MIDI sync delay.

Analog Feel. Which adds a random modulation to the sound to recreate an analogue synth’s “drift”. Not just on the pitch, but varying amplitude also."