Actually I didn't see the other post the extra osc. bank. It was called the little brother.

The playing itself part isn't broken. Depending which slider (left or right) in the mixer section is used, left = keyboard triggered volume from the vca; right opens the vca on the last pitch hit (unless the sample/hold is triggering the osc, then its random.

I bought mine before I worked at moog.(Although I kept it) Dr. Dave Luce (head of engineering, and polymoog designer) was sure that they were using the patented moog filter as well (it was encased in a solid block of epoxy). He spent about 2 weeks melting it through with a torch. After the lawers got involved arp had to change the circuit (mk2) and pay damages.

Definately blows away the micromoog. There was an optional add on oscillator bank (external cabinet) that would add a second voice in 1-4 octaves and different waveforms (it fit other arp models as well) I forget the name (I sold mine) it might have been extravoice or something like that.

Great filter swept pink noise sounds, and since the filter will self oscillate and track the keyboard to makes a great sine wave generator, especially used with the regular osc. (Think killer flute sounds) It allows nice sqare and triangle mixing. IT does nice sax patches as well.

I still have mine in its original arp/anvil road case. The mk1 is gold on black (instead of orange) and had a +/- 1 octave pitch bend knob with a dead zone in the middle (it beat the hell out of the ppc.)

I never used it as my only synth, but in combination with the moog's, or sequential circuits pro-1 (with programmer) boards I used with it it was a killer. I had a Hohner keyboard that did strings chello's electric piano , and harpsichord (I forget the model) strings were much better that the arp string ensemble; a Wurlitzer EP200 electric piano, and a Hammond M3 with 122 Leslie.

They were selling new around here, for about $650 (New York) I bought mine from the singer in a band I was doing sound for $200 2 years old and mint condition with the road case.

I own and love Moog synths, and was very surprised at the Moog-like sounds from this thing. I actually popped the hood to find out if it actually had the 4035 "Moog Filter" module but you can't see it unless you disassemble the front panel, so no go.

It definitely wasn't a 4023 filter, because if you crank the resonance on that filter it doesn't attenuate the low end. This filter does attenuate the low end, so it's either a 4035 or a 4075 filter. I regret not finding out, but man for a one-VCO synth it sounded sweet. It had to be a 4035...

Unfortunately this one had a dead ADSR and real dirty sliders. Something was wrong with the keyboard circuit. It's obviously been gigged and a couple of keys are not original. I couldn't justify the $350 price they were asking.

But it gets a better Moog sound than my Micromoog and it sounds great. And it has I/O jacks on the back, ready for external signals and MIDI->CV converters. They're a bargain these days. If you see one, snatch it up!