IK Multimedia's second hardware synth builds on the initial synth engine introduced in the Uno Synth, which was surprisingly beefy sonically if not physically.
Uno Synth Pro expands this original concept and adds - a more substantial build quality in both the desktop and keyboard versions, three morphing oscillators (playable as 3 note paraphonic), two filters - the original OTA filter and a new SSI resonant filter with design input from the legendary Dave Rossum, we also get an analogue post filter drive and three DSP send effects (maintaining the analogue path). Mod (Chorus, Phaser, Flanger), Delay (mono, Stereo, pingpong, LCR, doubler) with 1400ms maximum delay, and Reverb (plate, spring, hall, reverse).
We also have a capable 16 slot mod matrix, 64 step sequencer with 20 lanes of parameter recording, 10 mode arpeggiator and a pair of CV/Gate input and outputs.
Sonically, the Uno Synth Pro has real weight to the oscillators, they are really beefy. Although starting at Triangle, there is a certain amount of sawtooth bleed into that, it's not fully pure. Also when sweeping PWM in higher notes, there is a little dirt on the modulation, But they do have plenty of girth as I like to say.
The oscillators do run quite hot into the filters, which can be series or parallel, the OTA can is 2 pole Low pass or high pass with a 180 degree phase flip for some interesting vowel type sounds, these can be configured as 6pole Low pass, band pass as well as other parallel configuration, They sound pretty good and add a ton of character.
Modulation is provided by a pair of syncable LFOs that run to around 100Hz with a fade in parameter - waves: Triangle, Saw, Square, Random, S&H, noise. They appear to be bi-polar.
Envelopes are hardwired to VCA and VCF, but also can be routed further via the mod matrix, they can be very snappy and zappy when it comes to the filter and can also loop. One thing, the VCA can be rather clicky (same as happened with the minilogue) but it's easy enough to dial in a little attack and release to counter it, and having the super fast setting one can argue gives more ultimate flexibility - it's not broken though!
Mod Matrix - with 16 slots there are plenty of sources and destinations which include the CV and GATE ios to incorporate external gear. I would like to see FX parameters in addition to the send levels and perhaps a way to include unipolar modulation paths.
There are plans to expand and enhance this area of the synth, we know that there are plans on fade times for mod slots, adding A, D, S, R granularity to the slots.
FX - the star of the show is the reverb - the algorithms sound pretty smooth with Hall and Plate having up to 30 seconds plus separate control of the Low and High reverb times for quite powerful sonic shaping - I like it and when combined with paraphonic voices can make the synth sound more like a poly synth. Mod and delays are also decent, but not all that extreme in nature.
Sequencer and Arp - the sequencer is maximum 64 steps, though it's currently only locked to 16th there is no beat division function which I think it should, but it's a straight forward recording (step or realtime) recording process. Additionally you can record up to 20 parameters into the sequencer for automation or modulation, including without notes. These parameters are only the ones that are controlled by front panel knobs, not the deeper parameters that are accessed via the preset menu.
Arpeggiator offers 10 modes and also rather neatly can be recorded into the sequencer to capture the spontaneous moment.
Conclusions The UNO Synth Pro sounds great to my ears. It is a little rough around the edges yes, but sonically it's impressive. It's my current favourite mono. Due to the parameter access system, there is quite a lot of menu work and that is hard to see how that can be avoided and may not suit everyone, but I can confidently say that iit is worth the effort. There are plans for the librarian/editor, but thats not for a couple of months, so bear that in mind - no way to patch swap yet...
It's a cracking instrument and when you consider that the desktop version is around £399/$399 - it's in the realms of the current crop of Behringers but has a real sonic character of it's own. If you want the keyboard version, the extra £ seems a little rich (£699/$649), but the keybed is Fatar with aftertouch and the case is metal.
I would certainly recommend you check it out if you're looking for something which has plenty of character and weight.