These are not technically VA, they are based around FPGA chips (same tech as A4/AK/AR)
The difference is VA uses DSP to emulate analog sound, FPGA is an array of logic devices in one package that can be programmed, in this case to emulate the circuits of the original synths, hence ACB.
Are you serious - please can you explain a little more
Never heard this before
Cheers
FPGA is often used with DSP for real time processing because of low latency and flexibility. I think ACB is really Rolandâs way of doing VA.
But the same tech as the analog 4?
Interesting if true
Maybe for OS and Effects, but OS can live in a micro-controller instead.
The A4 uses a Spartan FPGA the Rolands use a Roland one, not exactly sure how they are being used but I thought it interesting that the Rolands do not appear to be using DSP chips.
I believe the A4 also uses OTAs\OpAmps for each of the voices, I assume the FPGA is being used for things like reconfiguring the filter type and switching and routing duties, whereas on the Boutique they might be used for the recreation of the DCOs, filters etc.
Marcus Fuller did a teardown video here:
Two different sources on operator-1.com say the Boutique synths are in a limited number worldwide (7k would be the definitive number for each type)
and are now discontinued.
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Bang ! GAS initiated for those who were hesitating
Sorry, but ACB is purely digital and software it canât be compared to A4 at all. Also mind, that Rolands ACB synths for the Aira-line are available as VSTis and sound exactly the same.
The FPGAs are NOT a sound shaping component at all, in both devices!
Oh sorry I know it is digital, FPGA is a digital logic gate array, also the Juno106 and JX3p had digitally controlled oscillators, as does the A4 so I wasnât getting into the analog vs digital thing. What I was saying is that a lot of people are calling the Boutique (and Aira) range VA, which is based around DSP emulating analog sound, ACB is different in that it emulates the circuit behaviour. The VST versions though are just VA emulation, same concept as any other VST analog emulation of any other hardware synth.
On my last post I said that I was not sure what the FPGA was doing in the A4 but guessed that it was for routing etc not sound generation per se, in the Boutique I think it is being used to generate sound, as according to the teardown video there is little else in there aside from the memory and some a/d converters, passives and opamps and other low level semiconductors.
But if anyone knows better then feel free to correct me.
Anyway, I have owned and used the originals for many years and I think that the Boutiques sound extremely close, and in some ways better than the original synths, and certainly miles better than any VA I have ever heard.
âmiles better than any VAâ not something Iâd agree with.
Have you ever tried u-heâs Diva? Or NIâs Monark? Theyâre the standard I tend to judge by.
âmiles better than any VAâ not something Iâd agree with.
@clunky - Ok, maybe"better" is too ambiguous a term I should have said âmore accurateâ and of course this is largely down to perception and preference of the individual. For me the Juno 106 sounds that I am well familiar with and love come easily from the JU-06 with no noticeable flaws typical of usual VA emulation, which for me are often most apparent in things like the filter response. On the JX-03 the envelopes seem a fair bit snappier than the JX3p and I actually prefer this as well as some of the other mods that the Boutiques have (faster LFO, more waveforms etc), the poly thing and small size are not issues for me, although I can totally see why they are for some people. I mostly make simple techno, acid and house so big chords and keyboard are not important for my dabblings 
Have you ever tried u-heâs Diva? Or NIâs Monark? Theyâre the standard I tend to judge by.
@smokyfrog - No I have not, but then I am one of those weirdos who wonât have a computer in the studio, Iâd certainly not be one to question your judgement though, in regards to my comment it is solely based on my experience of the Boutiques versus the original synths they are based on, I should have been clearer on that.
I should perhaps also point out that I can be something of a purist with regards to emulation of vintage synths by analog clones or modern digital emulations, I easily picked out the real SH-101 vs the System1 version in the blind test thread at muffwiggler and when it comes to the TB-303 I still wonât buy any clone, as so far none that I have heard come close enough for me. (the audiorealism one seems to be the best, but software) However the Boutique range are close enough to satisfy my particular Juno/JP/JX lust 
Im really surprised how different the real Jupiter 8 and JU08 sound in the Sonic State shoot out.
The Jupiter sounds so alive and organic, the JU08 sounds pretty clinical. That being said I thought the difference would be way more subtle. Curious to hear others opinions.
^ I have not tried the JP-08 yet as mine has not arrived but I have played an original Jupiter8 so I will know for sure once my JP-08 arrives. Note the Jupiter 8 has VCOâs and the Juno 106 and JX3p are both DCO based, so it might well be that the JP-08 wonât match the fatness of the original, which would not surprise me, but then again a Jupiter 8 goes for 10 thousand pounds now so my expectations are realistic
I had the Roland VariOS a few years back which had a Jupiter8 emulation, but it really wasnât anywhere close. I do know of a couple of high profile people who have the JP-08 and have owned or used the original and they seem to be very happy with the JP-08.
On the sonicstate video the Jupiter 8 seems to be a bit louder than the JP-08 in places.
Interesting about rolands custom FPGA. What is ACB after allâŚslew to replicate the inconsistency of vintage analog components. uheâs Diva does this with the slop parameter, IMO where the beauty in the sound lies.
Good point, the Juno and JX may be easier to replicate for that reason.
âNo computerâ sounds healthy 
Divaâs so good though, was the first modelled analogue that I found utterly convincing, not just in certain settings but at all settings it just handled properly. Monark is amazing and DCAMâs Synth Squad collection is not far off too. Iâve never heard anything as âaliveâ as those in a DSP/hardware synth, but itâs getting closer and Roland are doing impressive work with their ACB, however they do it.
To be fair, ACB is not just âslewâ or âslopâ between parameters. It is as mentioned above, a wholly different approach than traditional VA.
In traditional VA, you create an oscillator and then use digital methods such as filtering and envelopes to sort of recreate the analog synth using digital approximations of the analog components - they can be tweaked and slopped up, but at the end of the day, they are wholly different as they are built from components that inherently operate different than the analog counterparts.
Youâre creating a digital filter for example, any way you want, and then tweaking it to sound right.
In ACB (Rolandâs term for circuit modelling), you go even lower level - you emulate the circuits and the flow of electricity which eventually produces your oscillator and your filter, but again, its a very low level, so it matches almost exactly. Very powerful stuff that is really starting to penetrate the consumer realm.
Contrary to what I read above, Iâm not so sure that the VST versions are different, or traditional VA, as this circuit modelling is still software, and so would be reproducible on a computer.
For example, Maschine uses it in itâs sampler emulation. Universal Audio stuff uses it in almost all of their emulated software.
Got to try the Juno, and tbe Jupiter modules, and they are fuuuuuuuuuuuuun.
I still stand by this.