Korg Poly-61

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Poly-61
Korg-poly61.jpg
Poly-61
ManufacturerKorg (Keio Electronic Laboratories)
Dates1982-1986
Technical specifications
Polyphony6 voices
TimbralityMonotimbral
Oscillator2 DCOs per voice
LFO1
Synthesis typeAnalog Subtractive
Filter1 low-pass per voice
Attenuator1 VCA per voice
1 ADSR envelope per voice
Storage memory64 patches
Input/output
Keyboard61 keys
External controlPoly-61M has MIDI

The KORG Poly-61 (PS-61) is an analogue programmable polyphonic synthesizer released by Korg in 1982,[1] as a successor to the Polysix. It was notable for being Korg's first "knobless" synthesizer - featuring a push-button interface for programming, dispensing from the Polysix's knobs and switches. The Poly-61 also is using digitally controlled analog oscillators or DCO's (Roland's Juno-6 had made the same leap the previous year), in place of the Polysix' VCOs. The Poly-61 also boasted double the amount of patch memory (64 memory positions versus the Polysix's 32), but did not feature its predecessor's on board effects.

In 1984 a MIDI version, the Poly-61M was released featuring basic MIDI implementation, however, prior to that, a person could order a factory installed Poly 61 with MIDI in and MIDI out jacket installed on a plate on the rear of the keyboard; simply called Poly-61 with Factory Installed MIDI. The MIDI of the day was quite crude, relatively, with only note on and note off information. No velocity (the amount of force the key is pressed); no Aftertouch, (the programable parameter of what happens after Note Off) and other standards of today was missing.

Audio path[edit]

Oscillators[edit]

The Poly-61 offers two DCOs per voice. DCO1 provides sawtooth, pulse, and PWM waveforms. DCO2 has only sawtooth and square.

Filter[edit]

The filter has the typical controls for cutoff, resonance, keyboard tracking and envelope amount. Some of these are rather limited by the poor parameter resolution. Keyboard tracking is simply "on" or "off" for example, and resonance and envelope level (here labelled "EG Intensity") have only 8 values.

Output[edit]

The final component in the audio path is a VCA. It can be driven by the envelope generator or a CV/Gate pulse.

Embedded processors[edit]

NEC D8049C - 8 bits, 11 MHz (max.), 40 pins (DIP), Supply Voltage = 5V

There are 2 of them on the CPU board (KLM-509), one is a Programmer and the other is an Assigner.

The 8049 has 2 kB of masked ROM as well as 128 bytes of RAM and 27 I/O ports. The µC's oscillator block divides the incoming clock into 15 internal phases, thus with its 11 MHz max. crystal, one gets 0.73 MIPS (of one-clock instructions). Some 70% of instructions are single byte/cycle, but 30% need two cycles and/or two bytes, so raw performance is closer to 0.5 MIPS. The minimum instruction length is 8 bits and the maximum instruction length is 16 bits.[2]

Modulation[edit]

Envelope generator[edit]

The envelope is an ADSR type. All parameters can only be set to one of 16 values.

There are 6 SSM-2056 analog envelope generator chips used in the Poly 61, each being controlled by discrete 4-bit D/A converters. This means there are only 16 possible settings for each of the ADSR parameters.

LFO[edit]

The LFO (known as a 'modulation generator' on the Poly-61) is a simple triangle wave that can be routed to the DCOs or VCF. It has a variable delay before it is triggered.

Notable users[edit]

References[edit]

  1. ^ "POLY-61 Programmable Polyphonic Synthesizer (1982-11)". Korg Museum, Sound Make Up. Korg Inc.
  2. ^ http://www.datasheetarchive.com/shortform-datasheet/UPD8049C.html
  3. ^ Church, Terry (February 9, 2010). "Black History Month: Jesse Saunders and house music". BeatPortal. Archived from the original on April 24, 2015. Retrieved October 16, 2011.
  4. ^ "Jesse Saunders – On And On". Discogs. Retrieved May 23, 2012.