Roland MKS-50 by synthcoyote
I've long been a sucker for the sound of the Roland Alpha Juno series synths. While not as sought-after as the legendary Juno 60 or Jupiter 8, they are nevertheless wonderful examples of 80s synth tech. The MKS-50 represents the most compact of the MKS series rack-mount analog synths.
The voice architecture is identical to the Alpha Juno, with a single DCO per voice, featuring a sub-oscillator and pulse width control (and modulation)as well as noise. Each voice has a non-resonant high-pass filter followed by a resonant 24 db/octave low pass filter built on the classic Roland OTA filter architecture (specifically a IR3R05 IC). The LPF is not capable of self-resonance. A single LFO is available to modulate DCO pitch or HPF filter frequency.The effects section consists of a chorus with depth control.
The MKS-50 receives MIDI velocity data, and supports aftertouch control over the VCA, VCF, and LFO.
The preset memory features a ROM bank of factory presets as well as a user-writable bank. There are 64 patches per bank.
Because there are precious few front panel controls on the MKS-50, editing is best accomplished using an external editor. There are a number of options for this including Roland's own PG-300 programmer, the CTRLR software editor, and the excellent MIDIClub JunoCTRL (which I use). You can use the MKS-50 without a 'knobby' interface, but I don't really recommend it. With one it's easy and fun to tweak and dial in the perfect sound. Without one, it can be an exercise in frustration.
The sound of the Alpha Junos (and therefore the MKS-50) is relatively unique: with the DCOs able to generate complex wave shapes you get some pretty amazing tones, but also have access to more conventional Juno analog sounds using the simple sawtooth and square waves. The filters still have the classic Roland sound, and are really one of the best features of this synth.
A common problem with these is the failure of the chorus unit, which results in an oscillating crackling noise. The repair is relatively straightforward, but it's difficult to find techs who work on these.
In all, the MKS-50 gives you a lot of sound and capability in a small package. The only other 1U 6-voice analog synths you're likely to find are the Oberheim Matrix 1000, which typically cost far more.