Grp A4

The Grp Synthesizer A4 is an italian Synthesizer und the smaller brother of the Grp A8 and the bigger brother of the Grp A2. It is a brown wooden cabinet with a black metal frontpanel. The first glance would give you the impression of a semi modular synth. But it is not patchable by cables. But all typical and rather seldom used modulation connections are available by a multitude of switches, some multi stop rotary switches and knobs. All in all there are these sections in the box:

• 3 VCO, each with 6 waveshapes
  • sine
  • triangular
  • triangular + sawtooth ("sharktooth")
  • sawtooth
  • square/pulse + sawtooth
  • square/pulse
  and linear or exponential FM, PWM, suboscillators (selectable -1 or -2 octaves) on VCOs 1&2, sync on VCOs 2&3 to VCO 1, and more
• voltage controlled LFO 1
• LFO 2 with triangle and square/pulse wave
• Mixer for the 3 VCO and their 2 suboscillators, external audio-in, noise, ringmodulator
• 2 VCFs
  • lowpass filter with 1 to 4 poles
  • state variable filter with 4 modes
    • 2 pole highpass
    • 1 pole bandpass
    • 2 pole lowpass
    • 1 pole band reject (notch)
• Envelope 1 (loop-mode, autotrigger)
  • attack
  • (peak) hold
  • decay
  • sustain level
  • sustain time (for loop mode only)
  • release
• Envelope 1 (loop-mode, autotrigger)
  • attack
  • decay
  • sustain level
  • sustain time (for loop mode only)
  • release
• VCA
• Auto Pan with own triangle wave LFO
• Sample & Hold
• Noise source (white, pink)
• Envelope follower
• MIDI interface with 440 Hz tuninge reference tone
• analog stepsequencer (2x 8 steps or 1x 16 steps) with 2 quantisizer and flexible routing to individual VCOs pitch, VCOs PWM, VCFs. Variable gate length knob. different play and step repeating modes
• 1/4" CV and gate inputs and outputs
• MIDI In and Thru on the back of the housing. And the main switch and AC cable socket is there too. The USB port there is only for updating the firmware of the sequencer logic and the MIDI interface. It is not used for other purposes, so better don't use it unless you are advised to by Grp.

Impressive list of avaiable sections. And with the flexible modulation routings you get as much possibilities as a medium modular synth. And all this without getting tangled in patchcables. But on the other hand, you have to watch for nearly each and every switch unless you like unwanted things happen. So this is not for intuitive grab a knob and set a sound. But except for the MIDI interface and some more exotic possibilities of the step sequencers you will not need to read the manual if you are used to modular synths.

The LEDs are partly red or blue, depending on internal or external trigger or sequencer step modes. This is helping to get some more information without checking the switch positions. These switches are not bad, but if you are not straight in front of this synth, you might not see the switch positions that fast. But this is something that would happen on many modular synths as well, so it is not a problem of this synth design, but rather typical for all synths with such a complex and flexible modulation routings.

This is not a beginners synth. This is a serious synth you need to work on and have your mind on it you while patching. The sound is also a nice one. You get beefy basses to celestial tiny bells. Good classic analog sound. It is not sounding like a Moog or a vintage Korg. It never pretends to copy a classic synth character. This synth is a very well done compact synth for endless modulation fun.
Using it just for a bass or leadline would be like using a sports car in the rush hour.