Prophet 6 vs OB-6

Prophet 6 vs OB-6
« on: August 22, 2016, 05:33:29 AM »
Hey guys/gals,

I am looking at purchasing my first synth! Have stumbled across DSI brand in my forum trawling and have put my decision down to 2 options. The Prophet 6 or the OB-6.
Now as a noob to synths I am still not entirely sure exactly want type of I want out of the one I pick, I played classical piano for many years wasn't encouraged to dabble in electronic music, if fact it was frowned upon :(
I recently picked up an Ableton Push and have been loving the synth pads, etc and thought I owe it to myself to get a decent synthesiser. Main use will be mucking around with tunes at home.. I have loved some of the arpeggiated stuff I've heard on the Prophet 6 online as well as the Polyphonic tweaking, plus those 80s sounds are taking me right back to my childhood! Then on the otherhand, I've listed to this Youtube: DSI Oberheim OB-6 soundset - Peter Dyer, and was also totally blown away by some of the sounds the OB-6 is putting out.

What are your recommendations?
Cheers, Mike  :D

Re: Prophet 6 vs OB-6
« Reply #1 on: August 22, 2016, 05:45:30 AM »
They are both fantastic sounding synths and you can't go wrong with either. I think they're great synths to explore and to learn on, and both are pretty simple overall with everything right in front of you (very immediate and fun to create new sounds with them)

You can hear lots of demos on YouTube/etc but I think it might be best to try to find music stores nearby that carry these and give it a listen in person to see which you like more.

Enjoy!
Maru

Shaw

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Re: Prophet 6 vs OB-6
« Reply #2 on: August 22, 2016, 11:55:38 AM »
I'll second what Maru said... get thee to a Guitar Center (or other music store likely to have them) and try them both out.


Spend about 30 minutes with each, and get what you like.  Both are excellent synths, and excellent to learn synthesis on.  Either choice would be superb.


Shaw
"Classical musicians go to the conservatories, rock´n roll musicians go to the garages." --- Frank Zappa
| Linnstrument | Suhr Custom Modern | Mayones Jaba Custom | Godin Multiac Nylon | Roland TD-50 | Synergy Guitar Amps | Eventide Effects Galore |

Re: Prophet 6 vs OB-6
« Reply #3 on: August 23, 2016, 06:52:59 AM »
They are both fantastic sounding synths and you can't go wrong with either. I think they're great synths to explore and to learn on, and both are pretty simple overall with everything right in front of you (very immediate and fun to create new sounds with them)

You can hear lots of demos on YouTube/etc but I think it might be best to try to find music stores nearby that carry these and give it a listen in person to see which you like more.

Enjoy!
Maru

Thanks for your reply! Wish the music store was bigger here where I live 😜
Will go and check them both out when I next go to Melbourne. Is there any other synths you'd recommend me having a look at alongside these two?

Mike

Re: Prophet 6 vs OB-6
« Reply #4 on: August 23, 2016, 06:57:27 AM »
I'll second what Maru said... get thee to a Guitar Center (or other music store likely to have them) and try them both out.


Spend about 30 minutes with each, and get what you like.  Both are excellent synths, and excellent to learn synthesis on.  Either choice would be superb.


Shaw

Thanks! I will do as you suggested 😄 Would either one be more suited to trancey sounding synth sounds?
Also I read that the P6 doesn't send arpeggiated stuff through midi channel for recording? Is it the same on the OB-6?

Mike

Re: Prophet 6 vs OB-6
« Reply #5 on: August 24, 2016, 01:11:49 AM »
I just bought a OB6 Keyboard and a P6 Modul. I didn't had enough space for both in keyboard version and the OB6 looks just nicer to my eyes. Sound wise they can differ but somehow they have a lot in common as well. The OB6 is a bit more aggressive, has more high frequencies, sounds a bit wilder and is to my ears more interesting. The P6 on the other hand has the lushest and deepest pads, great arpeggio sequence sounds and just a huge sweet spot.

the Filter of the OB6 is just great. You can crank up the resonance it never gets harsh in your ears. That's the general nice thing about the OB...it sounds more direct but never harsh.

I just couldn't decide between the two...so I got both :):) maybe a bit of an overkill, but they are just great. The only negative thing for me, are the Modulation options which are really limited. Still both are capable of a lot of different sounds.

To sum it up, you cant go wrong with either of them. I have a tiny preference to the OB6, just because of its filter.

Re: Prophet 6 vs OB-6
« Reply #6 on: August 28, 2016, 12:13:20 PM »
I haven't had much time with my P6 desktop, but I wanted something to replace my long lost P5. And that it has done. Now, with the OB6 desktop out, I wanted to get this as well to compliment the P6 and give me some of the Oberheim sound I miss. I read differing things comparing these 2. So I took some time out to briefly test the OB6 keyboard and immediately found the sound different. I didn't have much time to play with it, but instantly decided I will get the OB6 desktop when it come out so I'll have both. These are such great designs, though I wish they were cheaper. Gear like this I plan to own forever (till death do us part!).

Re: Prophet 6 vs OB-6
« Reply #7 on: August 30, 2016, 05:08:15 AM »
I just bought a OB6 Keyboard and a P6 Modul. I didn't had enough space for both in keyboard version and the OB6 looks just nicer to my eyes. Sound wise they can differ but somehow they have a lot in common as well. The OB6 is a bit more aggressive, has more high frequencies, sounds a bit wilder and is to my ears more interesting. The P6 on the other hand has the lushest and deepest pads, great arpeggio sequence sounds and just a huge sweet spot.

the Filter of the OB6 is just great. You can crank up the resonance it never gets harsh in your ears. That's the general nice thing about the OB...it sounds more direct but never harsh.

I just couldn't decide between the two...so I got both :):) maybe a bit of an overkill, but they are just great. The only negative thing for me, are the Modulation options which are really limited. Still both are capable of a lot of different sounds.

To sum it up, you cant go wrong with either of them. I have a tiny preference to the OB6, just because of its filter.

Thanks for your reply, it's good to speak with people whom have both synths! As both of them are inspired by older synths can they be dialled in to create quite modern sounding sounds as well? In particular, the sound demos I have heard mostly of the Prophet 6 have a 70's/80s feel to them (which is awesome by the way!), but many of the patches recorded in this Soundcloud demo of the OB-6 sound quite modern: https://soundcloud.com/syntheticthings/dave-smith-instruments-ob-6-sound-demo

Is the Prophet 6 just as capable of making these modern types of sounds  (I guess in it's own less wild way?)

Mike

Re: Prophet 6 vs OB-6
« Reply #8 on: August 30, 2016, 09:40:22 AM »
Mike-

The programming structure of all of these sounds is possible with the Prophet 6.  However, the two machines will always have different characteristics due to the fact that the oscillators and filters are individual to each instrument. 

-dj

Re: Prophet 6 vs OB-6
« Reply #9 on: August 30, 2016, 10:42:09 AM »
I think the OB6 sounds more modern then the P6, or lets say you can integrate it better into any kind of modern electronic music. The P6 has more the Jean Michel Jare vibe, wich I love btw. But the OB has more edge, is more aggressive and wild. I just love the pads from the P6, as they are the deepest and lushest pads I ever heard. there the OB sounds more open and less smooth..mainly because of the filter db. Some days later I have to confess, both might be a bit of an overkill and if I Had to choose one, it would be the OB. But thats maybe because of the music style I produce (Psytrance, Chill out) where the OB just seem to fit better.

Re: Prophet 6 vs OB-6
« Reply #10 on: August 30, 2016, 10:13:21 PM »
Is the Prophet 6 just as capable of making these modern types of sounds  (I guess in it's own less wild way?)

Feel free to check the demos I recorded a while back: https://soundcloud.com/pauldither/sets/sequential-prophet-6

I'd say it's not necessarily bound to sound classic vintage all the time. You can do all kinds of more crazy stuff with the PolyMod section. What colors each of these synth's particular tone most is definitely the filter. So while I would say that both can actually also sound more contemporary, they will do it in differently flavoured ways.

Re: Prophet 6 vs OB-6
« Reply #11 on: August 31, 2016, 02:49:14 PM »
Mike-

The programming structure of all of these sounds is possible with the Prophet 6.  However, the two machines will always have different characteristics due to the fact that the oscillators and filters are individual to each instrument. 

-dj

Thanks, as this will be my first and probably only (at least for a while) synth I would love to be able to make a mixture of vintage and modern sounds with it :)

Re: Prophet 6 vs OB-6
« Reply #12 on: August 31, 2016, 03:00:27 PM »
I think the OB6 sounds more modern then the P6, or lets say you can integrate it better into any kind of modern electronic music. The P6 has more the Jean Michel Jare vibe, wich I love btw. But the OB has more edge, is more aggressive and wild. I just love the pads from the P6, as they are the deepest and lushest pads I ever heard. there the OB sounds more open and less smooth..mainly because of the filter db. Some days later I have to confess, both might be a bit of an overkill and if I Had to choose one, it would be the OB. But thats maybe because of the music style I produce (Psytrance, Chill out) where the OB just seem to fit better.

Does it go well for producing Psytrance? What other gear do you use in combination with it to produce it?

Would the OB-6 be suited in any way to modern EDM sounds as well? Thought it would be fun to have a dabble in a few genres

Re: Prophet 6 vs OB-6
« Reply #13 on: September 01, 2016, 01:29:57 AM »
I think the OB6 sounds more modern then the P6, or lets say you can integrate it better into any kind of modern electronic music. The P6 has more the Jean Michel Jare vibe, wich I love btw. But the OB has more edge, is more aggressive and wild. I just love the pads from the P6, as they are the deepest and lushest pads I ever heard. there the OB sounds more open and less smooth..mainly because of the filter db. Some days later I have to confess, both might be a bit of an overkill and if I Had to choose one, it would be the OB. But thats maybe because of the music style I produce (Psytrance, Chill out) where the OB just seem to fit better.

Does it go well for producing Psytrance? What other gear do you use in combination with it to produce it?

Would the OB-6 be suited in any way to modern EDM sounds as well? Thought it would be fun to have a dabble in a few genres

The Ob6 is good for Psytrance as it can sound quite aggressive. Squelches and hard LFO driven sounds are easy to achieve, even though I miss a Sine Wave on the LFO. In general the LFO sounds a bit clicky. Strange FX sounds are easy as well. Acidic leads ala 303 are great sounding. Band passed filtered leads etc...really cool.

Other gear I use for my productions: Virus TI, Little Phatty and Waldorf, of course loads of Softsynths like Omnisphere, Sylenth, Zebra, ABL Pro etc. FX I use only plugins like stuff from UAD, Soundtoys, fabfilter, Waves etc.

But the P6 is very useful as well. The Pads and chords sound super deep and thick. But the overall tone is just a bit reduced and kinder, less in your face. So I use it more for deep chill out maybe.

For classic EDM, House or Deep House both are equal good. Housy Chord sounds and stabs is where the P6 shines. Poly sounds on the Ob6 have more this 80s vibe. Reminds me a lot of Scareface score..lol

In general the OB has more edge and raw power. The P6 sounds always lovely, nice and warm. I really love them...even though I still think, having both is a bit of an overkill. One thing I noticed, on my P6 the build quality of the knobs is not as good as on the Ob6. They are not 100% centred and sometimes feel a bit scratchy when I turn them The big junky knobs on the OB6 are perfectly centred and no scratchy feeling at all.
« Last Edit: September 01, 2016, 01:47:43 AM by Motion Drive »

Re: Prophet 6 vs OB-6
« Reply #14 on: September 02, 2016, 10:19:47 AM »
In particular, the sound demos I have heard mostly of the Prophet 6 have a 70's/80s feel to them (which is awesome by the way!), but many of the patches recorded in this Soundcloud demo of the OB-6 sound quite modern: https://soundcloud.com/syntheticthings/dave-smith-instruments-ob-6-sound-demo

Is the Prophet 6 just as capable of making these modern types of sounds  (I guess in it's own less wild way?)

Mike

Hi Mike,

since you posted this soundcloud track as an example, can you point to some specific parts in the demo that you consider modern types of sounds?

Soundcloud lets you copy the URL for a specific time in a track, by clicking Share and then clicking the "at [time]" checkbox to the right of the URL. For example:
https://soundcloud.com/syntheticthings/dave-smith-instruments-ob-6-sound-demo#t=3:58

Re: Prophet 6 vs OB-6
« Reply #15 on: September 03, 2016, 08:20:10 AM »
In particular, the sound demos I have heard mostly of the Prophet 6 have a 70's/80s feel to them (which is awesome by the way!), but many of the patches recorded in this Soundcloud demo of the OB-6 sound quite modern: https://soundcloud.com/syntheticthings/dave-smith-instruments-ob-6-sound-demo

Is the Prophet 6 just as capable of making these modern types of sounds  (I guess in it's own less wild way?)

Mike

Hi Mike,

since you posted this soundcloud track as an example, can you point to some specific parts in the demo that you consider modern types of sounds?

Soundcloud lets you copy the URL for a specific time in a track, by clicking Share and then clicking the "at [time]" checkbox to the right of the URL. For example:
https://soundcloud.com/syntheticthings/dave-smith-instruments-ob-6-sound-demo#t=3:58

"Modern" is of course a bit subjective, so I'd rather call it everything beyond the typical analog poly synth stuff. But yeah, no problem. Here are a few examples:

https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=4:53
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=5:39
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=8:29
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=10:01
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=11:41
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=13:17
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=0:31
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=2:15
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=2:32
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=2:57
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=3:51
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=5:09
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=6:12
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=7:27
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=8:03
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=11:49
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=12:38
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=14:53
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=15:26
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=0:36
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=2:14
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=4:52
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=5:34
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=6:56
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=8:43
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=17:25
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=18:44

Re: Prophet 6 vs OB-6
« Reply #16 on: September 05, 2016, 06:24:44 AM »
In particular, the sound demos I have heard mostly of the Prophet 6 have a 70's/80s feel to them (which is awesome by the way!), but many of the patches recorded in this Soundcloud demo of the OB-6 sound quite modern: https://soundcloud.com/syntheticthings/dave-smith-instruments-ob-6-sound-demo

Is the Prophet 6 just as capable of making these modern types of sounds  (I guess in it's own less wild way?)

Mike

Hi Mike,

since you posted this soundcloud track as an example, can you point to some specific parts in the demo that you consider modern types of sounds?

Soundcloud lets you copy the URL for a specific time in a track, by clicking Share and then clicking the "at [time]" checkbox to the right of the URL. For example:
https://soundcloud.com/syntheticthings/dave-smith-instruments-ob-6-sound-demo#t=3:58

"Modern" is of course a bit subjective, so I'd rather call it everything beyond the typical analog poly synth stuff. But yeah, no problem. Here are a few examples:

https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=4:53
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=5:39
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=8:29
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=10:01
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=11:41
https://soundcloud.com/pauldither/sequential-prophet-6-demo?in=pauldither/sets/sequential-prophet-6#t=13:17
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=0:31
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=2:15
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=2:32
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=2:57
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=3:51
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=5:09
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=6:12
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=7:27
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=8:03
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=11:49
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=12:38
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=14:53
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-2?in=pauldither/sets/sequential-prophet-6#t=15:26
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=0:36
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=2:14
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=4:52
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=5:34
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=6:56
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=8:43
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=17:25
https://soundcloud.com/pauldither/sequential-prophet-6-demo-part-3?in=pauldither/sets/sequential-prophet-6#t=18:44

Wow! Thanks for posting direct links to each of these sound examples, they are AMAZING! Many of them are kind of modern I was thinking about... I have heard lots of OB-6 demos giving off similar types of quirky and cool sounds and notes, and was hoping that the Prophet 6 was capable of this type of stuff for some trance/fat bass/wierd and wonderful stuff too.

I watched the first episode to Stranger Things tonight, and was blown away by the synth sounds used in the opening title.. I guess both the OB and Prophet would be suited to similar arpeggios to that with similar filter effects? How did you get the arpeggiator recording out to Ableton Live?

Re: Prophet 6 vs OB-6
« Reply #17 on: September 05, 2016, 08:24:22 AM »
Wow! Thanks for posting direct links to each of these sound examples, they are AMAZING! Many of them are kind of modern I was thinking about... I have heard lots of OB-6 demos giving off similar types of quirky and cool sounds and notes, and was hoping that the Prophet 6 was capable of this type of stuff for some trance/fat bass/wierd and wonderful stuff too.

Thanks! Yeah, it's absolutely possible to get quirky and weird sounds out of the Prophet-6 just as much as randomly self-evolving drones. In that regard both the Prophet-6 and the OB-6 are technically capable of the same sonic diversity, although I personally would say that the OB-6's filter identity is always more obvious. But don't forget that you can also use the Prophet's high and low-pass filters to emulate a bandpass filter. All in all I have to say that given that both of these synths are fairly conservative in terms of modulation options, they surprisingly cover a lot of sonic territory. It's not that they only do typical pads, leads, and basses.

I watched the first episode to Stranger Things tonight, and was blown away by the synth sounds used in the opening title.. I guess both the OB and Prophet would be suited to similar arpeggios to that with similar filter effects? How did you get the arpeggiator recording out to Ableton Live?

I've read that they used a Prophet-6 quite a bit for the recordings: http://www.salon.com/2016/07/23/obsessed_with_stranger_things_meet_the_band_behind_the_shows_spine_chilling_theme_and_synth_score/

I'm not quite sure what you mean by the question about how I got the arpeggiator recording out to Ableton Live. I just recorded arpeggiated patches directly into Live. The MIDI data Live recorded were just the notes I played on the Prophet-6, but since the arpeggiator was activated on the according patches, the arpeggios would of course be reproduced during the playback for the audio recording. But in most cases I recorded audio and MIDI simultaneously anyway.

Re: Prophet 6 vs OB-6
« Reply #18 on: September 05, 2016, 02:02:43 PM »

I love how broad the Prophet-6 sound palette is compared to the Prophet-5. Although this has had some unfortunate side effects with people leaving narrow-minded / knee-jerk comments on youtube demos about how the Prophet-6 doesn't really sound like a Prophet-5.

No the P6 doesn't automatically sound like the P5, precisely because of the much broader sonic possibilities. After having used the P6 for about six months, I can get it to sound incredibly close to P5 patches, it just takes quite a bit of tweaking for each patch. I know this wasn't your question but I thought I'd just throw this into the discussion.

Re: Prophet 6 vs OB-6
« Reply #19 on: September 05, 2016, 02:52:11 PM »
I love how broad the Prophet-6 sound palette is compared to the Prophet-5. Although this has had some unfortunate side effects with people leaving narrow-minded / knee-jerk comments on youtube demos about how the Prophet-6 doesn't really sound like a Prophet-5.

Indeed. Don't know if you've listened to these audio examples (the first recordings posted in the paragraph "Les voix du maître"), a quiz that compares a Prophet-5 Rev. 3 and a Prophet-6 without saying which one is which:
http://fr.audiofanzine.com/synthe-analogique/sequential-circuits/prophet-6/editorial/tests/le-retour-du-roi.html

No the P6 doesn't automatically sound like the P5, precisely because of the much broader sonic possibilities. After having used the P6 for about six months, I can get it to sound incredibly close to P5 patches, it just takes quite a bit of tweaking for each patch. I know this wasn't your question but I thought I'd just throw this into the discussion.

It's true. And the example above proves that pretty well.