Korg Poly-61

Robert L's Analog Synths

Korg Poly-61

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Robert L's Analog Synths

Korg Poly-61

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Korg Poly-61 is the younger brother of the highly popular Polysix. Most of the items found today are burdened with more or less severe defects on the CPU board, caused by the leaking battery. But, as with the rest of its family, once this is remedied, and everything is adjusted and tuned in a proper way, Poly-61 becomes a surprisingly good sounding and reliable analog synthesizer.
   The major disadvantages, like the lack of dedicated knobs and switches, as well as the "strange sound character" as described by some people, are largely overemphasized. Namely, because of the simple and well organized programming matrix, similar to those on Poly-800, the former really doesn't turn out to be a big problem. There are in all three 2-digit LCDs, one for the program number, one for the parameter number, and one for the parameter value, so that programming is not as cumbersome as it could be. Also, the parameter that is changed as last prior storing the program, will await you when you recall the patch, being ready to be tweaked and adjusted if needed.
   And regarding the bad reviews of the Poly-61 sound --- they must have been written by those who didn't realize that they played unadjusted and poorly tuned synth! The original adjustment procedure is quite elaborate and time consuming task for a qualified and skilled technician, but once this is done, even the harshest critics would change their mind. In fact, you may find as many, if not more, excellent remarks about this synth, claiming that this is a great sounding synth that will inspire you.
   Poly-61 has 2 oscillators per voice, both declared to be DCOs. The DCO1 has a peculiarity that it is a VCO by the signal generation method, while the digital circuitry serves only to trigger it and to ensure digital precision stability. So, stable it is, and, in difference to other DCO synths, sounds more analog, more generic, and more "VCO like" than all its competitors, including Roland Junos.
   The second DCO is a typical digitally controlled oscillator. Its square wave is as correct as it can be, but the sawtooth wave, because of only 4-bit resolution, is far from ideal. Probably the constructors had to cut corners and judged that it is good enough for the sole purpose of fattening the excellent DCO1. In the early models the sawtooth signal was simply made by the closest rising step-wise function, and because of that a too loud audible higher harmonic distorts the signal. The remedy was to modify the signal to look a bit different and this was implemented on the later models. If your Poly 61 has the above problem, you should have it serviced to implement the modification (you can send the voice board to us for this and for the full adjustment procedure).

As is well known, the second oscillator is very important for many sorts of sounds. With a slight detune it will produce the natural chours effect with the rich and fat sound which just isn't there with only one oscillator. Especially so in the lower and bass region, leading to the Poly-61 basses which are stronger and punchier than those on Polysix, and much fatter than on Junos.    Regarding electronic quality, Poly-61 is quieter than Polysix and many of its competitors. The background noise is better suppressed, though this comes partly from the fact that signal path is shorter and simpler without the effect board. The envelopes are completely analog --- the same SSM 2056 chips as on its predecessors, Polysix and Trident. Although the SSM 2044 filter chips are no longer present, the Korg's original filter still preserved the Trident/Polysix- Moogish character.
   The available sound parameters are pretty basic ones, that's true, but they are well chosen and organized, and all written on the front panel. A few of the parameters would benefit from more precise control, but luckily these are not the all important VCF cut of frequency, envelopes and the modulations.
   Sound-wise, Poly-61 is capable of producing very fresh and unique timbres, across the entire range of analog synthesis. Even the effects and ambient sounds come out great and interesting, which confirms the well designed layout. The factory patches are excellent, readily usable, and also serve as a good basis to start experimenting and building your own sounds. A few other banks that circle around on Internet have sounds that are really inspiring and that present this synth at its best.
   Highly useful is a versatile arpeggiator and an extra LFO modulation source for vibrato and growl effect, controlled by the popular Korg joystick. It has a dedicated frequency knob, which is extremely handy. There's nothing easier than adding a touch of good modulation on Poly-61, and you'll soon appreciate this feature.
   At the end, it's honest mentioning that this synth is usually compared to others, like Polysix, Roland Junos and similar synths from the period of early 80s, which all have choruses or similar effects. Put an outboard modulation on this synth and it will shine in most of the sounds it is capable producing.
   In short, Poly-61 is one of the few highly underrated synths, partly because being overshadowed by its older brothers, and partly because it has to be fully functional and adjusted to give its best. Then it's only up to you to use this synth creatively, and discover its amazing world of beautiful analog sounds. (The picture is gratefully taken from Vintage Synth.)