GRP A4 – Series 2015

Paolo Groppioni never dreamed that his GRP A4 synthesizer would be such a success. The synth is now in its 4th edition. To be honest, that doesn’t mean that thousands and thousands have been sold: really, truly, less than 150 GRP A4 have been built up to now. Handcrafted thru and thru, of course …


Despite strong competition on the lively market, the GRP concept remains singular (as it will in the future).

The synth has, as we all know, 3 VCOs, 2 sub-oscillators, 2 VCFs, ring-modulation, cross-modulation, S/H, 2 loopable envelopes, 2 LFOs (and much much more, including a tricky 2×8 step sequencer).


The BEAUTIFUL and UNUSUAL remains the comprehensive, pre-wired modulation matrix. That sets the GRP A4 apart!

Need to route VCO 3 to VCF 1 frequency? No problem, just turn a knob and specify the exact amount of modulation. Need to route sequencer track A to LFO 1 speed? No problem, just turn a knob and … well, you get it!


Or … you need to synchronize Sample/Hold with LFO 1, the sequencer and auto-pan? Flip a couple of switches and that’s it …

In addition to this myriad of modulation possibilities, you also have precise dynamic controllability via MIDI at your fingertips. Exclusive ranges of expression, subtle sophistication.


Velocity, aftertouch and MIDI Clock can be routed to many of the instrument’s parameters. Given, of course, that you do know how to play a keyboard (or, at least, how to program a software sequencer to get that dynamic control you’re aiming at).

As the cream-with-cherry-topping on the huge amount of information you already have about this instrument, we offer you our GRP A4 test report. Lots of synth details, lots of soundfiles … read about, think about …


For those wishing to study / print the GRP A4 in detail, here is the complete A4 Panel as a JPG download. We also offer 8 new soundfiles, the result of a spotaneous session triggered by an itch to just have fun with this extraordinary synthesizer …

GRP A4 – for orders / information contact Paolo Groppioni:
Email: .


Synthesizer / Sequencer / MIDI / CV+Gate

Price: 3.777 Euros + VAT + shipping costs


Comments are closed.