DSI - Mopho & Tetra

Anyone have any experience with these?

I've been looking at the possibility of getting one as my first analog synth. Any comments about these products would be welcome, thanks

I've a mopho (desktop). It's not my first (or only) analogue synth and I own digital (also known as "virtual analogue") synths as well, but it's become my "go to" synth for all kinds of things. I reckon it's a solid, good-sounding little instrument at a bargain price that doesn't sound or feel cheap.

To try to clear up the "is it really analogue" debate, the signal path in the Mopho and Tetra is entirely analogue. However, the oscillators are digitally controlled and clocked analogue sources. This means they don't quite sound like a 1970s style VCO/LFO (perhaps) but also means that they aren't tempramental, are pitch and tempo stable (VCO drift can be dialled in if you want it) and don't need time to warm up. Digital control also helps to keep the price down as well as allowing patch recall, programming via PC etc. The filter uses an analogue Curtis chip. Overall, digital sounding it is not.
 
Digital control of the analogue circuits also means the audio doesn't pass through the controls - so no risk of noise from dirty pots.

The built-in (pretty basic) arp, (not so basic) 4-track step sequencer and large number of routable modulation sources are very useful and very flexible. You could build a modular to do the same things, but you'd need far more money (and space).

The interface looks a bit sparse, but the ability to program 4 encoders to do different things in every patch plus the visual feedback from the LCD (generally showing function, original value and current value) makes it surprisingly usable, even live.

Sound - I like it, you may hate it - and there is a definite Dave Smith/Sequential Circuits sound. There's loads of DSI stuff on Youtube, some good, some bad. Listen and compare the Mopho/Tetra with other synths.

If you do get a Mopho, check which OS it's running and if it isn't download v1.4 and update it. v1.4 adds a few useful functions and updating via MIDI is straightforward.

Downsides? MIDI control rather than control voltage, so you can't quite get the seamless smoothness of a CV controlled synth, but there's no noticeable filter stepping and little noticeable pitch stepping either. You also save the cost/hassle of a MIDI to CV convertor. No built-in effects other than the (very good) overdrive.

A few things (e.g. cutoff) use MIDI NRPNs rather than the usual CC 0-127 to increase the range/number of steps available. Sonar handles this with no problem (the synths send MIDI from every control as well as receiving it, so recording e.g. manual filter movements is no problem). Some DAWs don't seem to know about NRPNs (or even all CCs)....
 
The catch is that there are something like 0-14,000 NRPN values, so a control that only uses e.g. the first 0-160 doesn't show up too well in Sonar's PRV controller pane without extreme zooming. Most controllers can't send values outside the 0-127 range (can any?), but that's what the Mopho's knobs are for.

For an analogue synth (analogue anything!) it's pretty quiet but there is a very slight VCO bleed-through, depending on the settings, when the synth is supposed to be silent; which is true of most analogue synths - though some digital synths also emit quite a bit of noise.

If I were to ask for one improvement it would be replacing the cutoff and resonance controller's endless encoders with potentiometers - though I believe that the Tetra already uses pots for those functions.

The Soundtower editor's a little quircky but not bad at all (especially the "paid for" version), and once you get it working (not too difficult) lets you get at things much more easily than trying to programme the desktop units from the front panel.

Running the editor and Sonar at the same time isn't a problem if your MIDI interface has a multi-client driver which allows more than one app to access the driver at the same time (most do, apart from ones using the generic MS driver); failing that MIDI-Ox can do the necessary routing. I generally have a couple of Soundtower editors open alongside Sonar without problems.

Having sung the Mopho's praises I'd suggest you also consider the MFB synths, Doepfer's Dark Energy, Analogue Solution's Semblance and the Vermonas. All are different, all can sound good and all are in the same kind of price bracket. As is the somewhat different/somewhat similar DSI Evolver.

A gentle warning - once you get one good, distinctive hardware synth (especially an analogue one) you may find some of your VSTis start sounding a bit bland and feeble in comparison :-)