Ultra-Analog: GRP A2

[marino]

 

The Italian synthesizer industry, once full of initiative and ideas, is in poor health these days. The reasons are complex and involve global economics, more local-specific considerations, and several other aspects; but the practical result is that while in England and France (to name two other European countries) several young companies are growing and innovating, at the moment there's little in Italy for the synth lover. There are a couple of great organ makers, there's Studiologic and a few others with their stage instruments, a few clever guys are making Eurorack modules, but not much else.

With a few exceptions: A couple of companies are making analog integrated synths. One is IK Multimedia, which recently stepped into the analog hardware market with the Uno Synth line.
Another one is GRP - quite a bit older, and targeting a whole different kind of customer.

 

 

A BIT OF HISTORY

 

For the last 15 years, Paolo Groppioni has been designing and building top-class analog synthesizers in his home laboratory near Rome, under the company name GRP. Actually, Paolo started almost 10 years earlier, around year 2001, with the A6 and A3 models; those were special-made instruments, produced in just a couple of units each.  In 2009 came the first commercially available model: The majestic A8, a huge six-oscillator monster that's not made anymore. Then in 2012 came the A4 with 3 oscillators, two filters and a whole lot of functions; in 2015 the A2 with two oscillators and a single multi-mode filter; and the recent A1, a little single-oscillator beast. GRP also makes the R24 sequencer, the V22 analog vocoder, and a series of Eurorack modules.
Paolo produces limited runs periodically, for which there's a constant - and growing - waiting list. All GRP synthesizers are entirely analog in every aspect and are assembled by hand.
At the end of the A2 manual you find blank sheets, which makes sense for an instrument with no patch memory; this is, to a large extent, an integrated synth, so a representation of the knobs' position is sufficient to allow an accurate recall of patches.

 

Over the years, two main aspects have defined the GRP approach: One is the search for high-end analog sound, through accurate design and the use of top-quality components; the other is an effort to include as many functions and modulations as possible, *without* the use of patch cords. This is achieved with a clever system of rotary selectors, offering a choice of modulation sources for several parameters; a layout not shared by many other manufacturers. It's not 100% versatile as using a modular system, but it's fast and clean, and in my view, it adds a lot to the 'quick gratification' factor while tweaking. I absolutely enjoyed my time with the A2.
Back to the first aspect, the search for absolute quality brings a side effect: GRP synthesizers are expensive. For the A2, at the moment we're talking about 1500 Euro plus VAT, so around 1780 Euro in total: Not cheap. Btw despite their prices GRP instruments are enjoying considerable success, with a growing customer base, and they are used by artists like Jean-Michel Jarre (who displays an A4 in his current live set), Tangerine Dream,  Hans Zimmer, Jordan Rudess, etc. So there's obviously a number of synth enthusiasts willing to spend their money to have a top-class analog sound.

 

Paolo was so kind to personally lend me an A2 - his "middle ground" instrument - to make a little video, so of course I'm also writing a review for KC. And this time I'll try to write a proper *review*, without neglecting any detail of the instrument - including the arpeggiator.
On with the review.

 

 

APPEARANCE

 

 

The A2 looks and feels very solid. The panel is clearly laid out, with the right spacing, and the knobs feel smooth and precise. I just needed a couple of clarifications from Paolo about terminology, then I never had to consult the manual, during my whole A2 experience. The lighted VU meters add a touch of class.
Connections are spartan: Audio (stereo) and Phones outs, CV/Gate ins, CV ins for a few other functions, and Clock in.
I wasn't too happy about the 'external' power supply. There's a recent trend of external PSUs even in high-end instruments: Osmose, Matriarch, Iridium Keyboard, Hydrasynth... the A2 is in good company in this respect. At least this one is very consistent, and it's of the type with an in-between box and a connector for a regular cable, so you can choose your preferred cable length.

 

 

STRUCTURE

 

The A2 includes two oscillators, two LFOs, a Sample & Hold, two envelopes, a white noise generator, a ring modulator, a 12 dB/oct multi-mode filter (LP, HP, BP, Notch, Stereo LP+HP), and some clever ways to connect them. It also has an arpeggiator.

 

 

OSCILLATORS

 

 

The two oscillators differ somewhat, and the combination of their features makes for a good variety of configurations.

 

- VCO 1 has triangle wave, "sharktooth" (saw + triangle, similar to the Minimoog), sawtooth, square with PWM, and a square/saw mix, of which you can adjust and modulate the width too.
Of course you have a couple of knobs for fine and coarse frequency, and an octave selector. But the real treat is the selector for frequency modulation: one of 11 sources can be selected, with an amount control. Choices include the two LFOs, S&H, the two envelopes, mod wheel and aftertouch - but also the other oscillator, noise, the ring modulator, and the whole output of the VCF! How's that for some audio rate madness...

 

- VCO 2 has square wave, narrow pulse, sawtooth, "sharktooth" and triangle; but the last three can be also used in "Super" mode. Yes, it's the same concept of the "supersaw" wave pioneered by Roland and implemented in many VAs and softsynth: A maximum of eight additional 'clones' of the main waves can be applied, with the "Shape" knob. Only, on the A2 this is achieved entirely in the *analog* realm. And it sounds smooth and creamy; especially the "supertriangle" has a luscious sound.
The same mod source selector from VCO 1 is present here too, with its own amount control. VCO 2 can also be synced to VCO 1, and disengaged from keyboard control.

 

There are controls for Portamento rate and Pitch Bend range; if desired, VCO 1 can be disconnected from either of these, or both.

 

There is no Mixer section per se; each sound source (the two oscillators, the noise generator, and the ring mod) has volume knobs in their respective sections.
Speaking of witch: As in many analog synths, gain staging is important. Different volume levels gently color the sound.

 

 

NOISE - RING MOD

 

They share a small section on the panel, with their respective volume knobs. Noise is only white, and RM takes the pre-mix signal from the two oscillators. The output of the ring modulator can be fed to the audio mix, of course - but what's really interesting, it can also be used as modulation source in several internal "patching points".

 

 

FILTER

 

 

GRP calls it a "State Variable" filter, but I prefer to say "Multimode", because you can select Lowpass (2-pole), Highpass (2-pole), Bandpass (1-pole), and Notch - but there is no continuous transition between the different states, Oberheim-style; you can only choose one at a time. There's also a stereo mode, with LP and HP panned left and right.
I have to say that this filter just sounds glorious. Rich, full, smooth, and just right to my ears. At high resonance levels, it totally screams, in a good way.
Other than the usual cutoff, resonance, envelope amount (positive or negative) and keyboard tracking, we find a "Dist" control - a filter overdrive, which makes the sound bigger, without breaking or flattening it. I used it quite a bit in the video.
Then there's the selector for a modulation source, with its own amount control. Ready? In addition to its own envelope, you can modulate the cutoff with the amp envelope, one of the LFOs, aftertouch, pitch bend wheel, mod wheel - and in the audio range, you have VCO 1, VCO 2, ring mod, white noise. Very good.

 

 

LFOs

 

- LFO 1 has a choice of square, triangle, saw and ramp (reverse saw). It can be directed to one of the oscillators or both, and/or the filter cutoff, via the selectors and amount knobs on those destinations; it also has a direct connection with PWM of VCO 1. The mod amount can be scaled with the mod wheel or aftertouch,  or fixed. It can run freely or start its cycle at keypress. A great option is to modulate LFO 1 rate with LFO 2, key tracking, or external CV, with dedicated amount control. This opens some very nice options.

 

- LFO 2 is - well, it's really much more than an LFO.There's a selector with a choice of square and triangle waves - then on the following clicks, instead of more waveforms, we read LFO1, VCO1, VCO2, RM, VCF OUT, WN (white noise), EG1, EG2, S&H. Huh?! Well, when we set the selector to one of those positions, the mod bus actually replaces LFO 2 with one of those sources; which means that when you select "LFO 2" as a mod source for an oscillator of filter, they are actually modulated from those modules. This really adds a myriad  of possibilities.
And that's not all: LFO 2 also has a separate, independent connection to the oscillators and/or the filter cutoff, with individual amount controls. - which can be scaled by aftertouch or the mod wheel. Excellent.

 

 

SAMPLE & HOLD

 

The S&H module is very interesting; when coupled with some creative thinking, it has a lot of potential. You can choose the signal being sampled between LFO2 and noise. But other than sampling the incoming signal at clock speed or according to an external clock, you can decide to sample at keypress, which can be fun - and wild, depending on what and how much you are modulating. You can also decide to fire the envelopes - or not - at every cycle, even using the keyboard as a gate control for that.

 

 

ENVELOPES

 

 

- Env 1 is the filter envelope - but it can also be directed to other destinations, as we've seen. In addition to the usual ADSR segments, it has a Sustain Time, active when the envelope is looped. The looped envelope can be triggered by key press, the Sample & Hold, or always running, sequencer-style.

 

- Env 2 is, by default, the amplitude envelope, and it's just an AR (Attack-Release). Its behavior can be switched to AD (Attack-Decay), which helps somewhat; in AR mode, Sustain is at max level, and in AD mode it is at zero. Anyway, it can be set in Hold mode (for drones, etc.) and put under CV control.

 

The A2 envelopes always respond to key presses in multi-trigger mode. I missed the chance to switch to single-trigger, which I find very useful for certain playing techniques.

 

 

ARPEGGIATOR

 

A rather linear arpeggiator. You have control on arpeggiator type (up, down, up/down, random); gate (note duration); subdivisions (4, 8 or 16 per pulse); octave range with a maximum of 4 octaves. Every note can be repeated 1, 2 or 3 times, and arpeggio rate can follow internal clock, MIDI clock, or external CV pulse.

 

 

CONCLUSIONS

 

Playing and tweaking the A2 has been a treat. The overall sound  is big and smooth, with a giant sweet spot. Sound is clearly the strong point of this instrument: Large, generous, satisfying analog sound. I'd likely use it as a practical explanation of how analog synths can't still be replaced by software - without using too many words.
The system of setting modulations with rotary selectors makes for very quick programming: I adapted to it almost immediately, and I had great fun.
Of course you don't get the monstruous versatility of the Sequential Pro 3, for example, where you can modulate everything with everything, with multiple sources and destinations and in any amount; that's due to the fact that GRP makes a point of keeping the whole structure in the analog realm, including the envelopes, lfos and all internal patching. While this approach is a substantial factor in creating the overall sound, there's a physical limit to the internal connections that can be established. With these premises, I'd say the A2 does a great job of offering a large number of possibilities. Of course its big brother, the A4, is even more capable in this regard, and it can be considered a veritable "modular without patch cords".

Negatives? Price aside, the only significant thing I can think of is, I really wish to have the option of switching to single-trigger response from the keyboard. For my own playing, I find it very useful on certain types of sound. Other aspects fall in the general "on a synth of this class, I wish..." category: External power supply, AR/AD amplitude envelope.

 

 

THE VIDEO

 

I made the video in two separate rounds; you can tell them apart by the different keyboard controllers and stands in the video. I had fun making that first half, but later I felt that I had not used the instrument to its full capacity; so I asked Paolo to lend me the A2 again, to really tap into those modulations. I only had an afternoon to spend for each round, but I feel that in the end, I was able to produce a few sounds that do some justice to the instrument's possibilities. I struggled to keep the video short... I had recorded enough material for at least two more of the same lenght.
I couldn't resist applying a *very* slight amount of ambient effect.
A little disclaimer: I don't know what happened to the video quality... it was probably my old camera that developed some problems. In any case, the video quality is horrible, and I didn't realize it until it was too late. I tried to improve it a bit with editing - with poor results. My apologies.
(Final note: toward the end, you'll see that little moths love analog synthesizers!) 🪰

 

 

 

[Doerfler]

Your video, CM, popped up on my YouTube homepage today as I am subscribed to your channel.  I had watched  (and liked) the video before I saw this post.  Thanks for all you do to educate us. 

[marino]

16 hours ago, Doerfler said:

Thanks for all you do to educate us. 

 

Er, educate who?!

This forum is a repository of expertise and talent...

 

My main aim is to provide information about instruments which might be less popular in the USA.

 

Actually, this was the same target that Stephen Fortner suggested when we talked about writing reviews for Keyboard Magazine. The excellent dB recommended me to him, and Stephen expressed interest in reviews of "less-known European instruments". I liked the idea a lot, and I wrote my first review about the Hypersynth Xenophone. Well, that wasn't exactly European, but not so far from the border - plus you have to start somewhere.

Unfortunately, shortly after that, Keyboard Magazine started having difficulties, and ended up closing its doors... but maybe this is a good place to reveal that the next review that was planned was about the GRP A4, the A2's big brother. (at the time, the A2 wasn't out yet)

So this review is closing a circle for me, so to speak. Hope it can be of some interest to KC members.

 

 

[David Emm]

Oh, for sure! This was like a blast-from-the-past Keyboard Report. I'm an unlikely buyer, as I just don't seem to have a mental jack for modulars. That doesn't mean I'm not fascinated, because if I went there, smartly compact instruments like this would be my go-tos. Purists would snort at my pile and ask why I didn't have it all one big cabinet. Tough! The A2 has an immense voice; it'd be a central prize in a rig.   

[NewImprov]

Damn, a very impressive synth, and it hadn't even appeared on my radar. Great sound! Of course, Carlo can make anything with keys sound awesome. Thanks for sharing this!

[The Real MC]

Nothing says "OLD SCHOOL" more than VU meters.

[The Real MC]

I always reduce video to 1024x720 before uploading to YT.  It will still get compressed but not horribly grainy.

[marino]

On 7/20/2024 at 6:08 PM, The Real MC said:

Nothing says "OLD SCHOOL" more than VU meters.

 

Yes! And also big, good knobs on a large panel.

 

 

On 7/20/2024 at 6:30 PM, The Real MC said:

I always reduce video to 1024x720 before uploading to YT.  It will still get compressed but not horribly grainy.

 

Well, in this case I'm almost sure there were problems with the video camera, because I noticed the issue while editing, much before uploading the video on YT. While I was shooting the video, I had set up the lights and the camera settings exactly like in previous videos, but the outcome was so bad that for the first time ever, I had to attempt corrections in the editing stage. It was only partially useful, and it added some artifacts to the image (you can notice that on my hands, for example).
Btw, thanks for the suggestion, I'll give it a try.