From what you’ve described the P6 and the OB-6 (although a bit over your budget) seem to be amongst the best candidates. Both are great synths but I prefer the organic and lush sound of the OB-6 which for me is one of the best polyanalogs that came to market in the last 30 years.
Depends also a bit if you want that classic Prophet sound or if you prefer the Oberheim SEM-aesthetics which IMO would be a better addition to your setup than a Prophet.
The Rev2 desktop is likely within your budget. it has the most modulation of any of their range (so far as I understand it). It sounds pretty good and has a huge range. I agree with the often-claimed “brassiness”, but you can work around it. it has effects you don’t need, but that means you can use the HPF more often (as it’s an effect rather than an analog filter). I find HPFs essential as I don’t have a mixer at the moment (and I love band-pass sweeps).
I’m fond of mine, but perhaps not in love. It’s not quite as knob-per-function as I’d like, but it’s close. I’m often tempted to sell it, to fund a P6 or OB-6, but I suspect I’ll miss the multi-timbrality and extensive modulation.
All Sequentials are great. Within their family, they’re quite different, though. So it all depends on why you want to own one.
For the most clean and true interpretation of a classic analogue poly - Prophet 5.
For as experimental and out there as you can get without being silly - Prophet 12
For the most modern and classy analogue sound - Prophet6 or OB-6
For modular and sound design mayhem, if you’re okay with paraphony, not polyphone - Pro3
For a good all around package that won’t rob you blind - Take5
If you’re shopping second hand, the original Prophet 8 has great character and the Pro2, some say, is even funkier than the Pro3 in its field. For experimentation and alien sounds, the Evolver is quite the creature. Mopho and Tetrade, I’d say are dated by now. And the Tempest is a beast all its own. An instrument you want to love, but try as you might, eventually you will abandon it.
I’m fully restricted to desktop models! Every inch of my space is allocated at the moment. I struggle to put coffee on the desk when I’m working on something.
The P6/OB6 modules are about 21 inches wide and the Take 5 is 25 inches. If you have any keyboard in your current setup, it might be worth considering replacing it with the Take 5.
I guess it’s a manufacturer that are highly respected and has history. Also, a large factor, they create desktop models which is something that is essential in my setup.
I’ve developed a deep affinity for dave’s synths over the years. I’ve never outright disliked any that I’ve been able to lay my hands on but I’ve been least blown away by the mofo and tetra.
I’d basically agree with @circuitghost assessment posted earlier as a fair description of each. There was a time not long ago that some of the older boards could be had cheap (p600, et al) but that ship seems to have sailed.
I currently use a pro3 and an evolver (desktop) and love them to bits. If I had either more money or less sense I’d absolutely own more of his stuff. I’m always keeping an eye out for the right deal at the right time on a p12 or an mek.
I just find sequential stuff so fast to dial in amazing sounds though a lot of people have the opposite experience. Mod matrices for life!
I would go for Rev2 over OB6 or P6. you said you wanted lots of modulation options, and the OB6/P6 are pretty limited there. lots to dive into with the Rev2.
Sequential is a very expensive habit… it’s is better to just decide on your favorite and just stick with that one… I would very much recommend the keyboard version. Even if you don’t have room or can’t play keys… get the keyboard… it is a much better experience.
I have a p6 and it is everything… it is in another class from everything else I own…
I totally agree. I have the OB-6 and that synth is magical, I’m sure the P-6 is also. Nothing in my collection can even come close to what the OB can do. It’s such a beautiful sounding instrument.
Without nitpicking you’re mostly covered for what DSI sequential offers.
Anything other than a P6 P5 or OB6 wouldn’t be a remarkable addition. And those three are pretty much too expensive for your budget. My advice as a Rev2 P6 OB6 owner, is wait for the Boberheim OB8 clone.