Yamaha SK20 — Sigur Rós Organ, String Machine & Synthesizer

No talking demo of the Yamaha SK20 Symphonic Ensemble from 1980; famously used by Sigur Rós on their “Ágætis byrjun” album.

00:00 - Intro: cover of Sigur Rós — Svefn-g-englar
02:30 - SK20 String Machine into Phaser
03:03 - cover of Jean-Michel Jarre — Oxygène (Part IV)
05:46 - cover of Joy Division — Love Will Tear Us Apart.
06:56 - SK20 Organ Section
07:28 - cover of Air — Kelly Watch The Stars
08:47 - SK20 Synth Section Demo
11:33 - SK20 Synth/Organ Split Mode Demo
11:56 - SK20 String Section Demo
13:10 - Various SK20 Sounds
14:50 - cover of Metronomy — The Look
16:34 - Outro: SK20 Organ Demo

In the early 1970s, Yamaha developed transistor-based analog organs with advanced synthesis features (compared to previous organ-only instruments like Vox Continental and Farfisa): Electone EX-42, GX-707, GX-1, GX-2, EX-1, EX-2. 1976, the famous CS series poly synths followed: CS80, CS60, CS40. Already starting from 1970, string machines had become popular: The most famous one, the Eminent/Arp Solina (1974), also derived from an analog home organ, the Eminent 310. Yamaha followed this trend a bit late with the SK series: The SK10 (1979) had string and brass sections as well as an organ, the SK20 (1980) replaced the brass section with a more flexible synth section.

A typical feature of string machines is their paraphony: A Solina has full polyphony on oscillator level (meaning, you can press as many keys as you want and they will still make a sound), implemented with octave divider technology. But while polyphonic synths like the CS80 or the Prophet V have a volume envelope and at least one filter with a filter envelope per voice, most string machines only have one global envelope and one global filter. The SK series sits in the middle: The SK20 has no full polyphony on oscillator level, but rather 7 voices; in split modes 7 for the organ section and 7 for the strings/poly synth section = 14 in total. While there are dedicated volume envelopes per voice, there is only one global filter and filter envelope.

In this demo, I’m playing the SK20 through a Meris LVX doing different kinds of delay, reverb, chorus and phaser effects; on the solo demo parts directly into an IGS Volfram Limiter (Urei 1178 compressor clone), on the full songs into the Ext In of the Elektron Analog RYTM Mk. II, which then goes to the IGS Volfram. From there, the signal goes into a RME Fireface UC, and is recorded on a Cubase stereo track. The Novation Peak which is used on some tracks, MIDI-sequenced by the RYTM, goes directly to another pair of Fireface UC audio inputs. Guitar (Reverend Club King 290) played with an e-bow through a Line6 M5 on chamber reverb into a Kingsley tube overdrive into a Strymon Timeline on tape delay, in stereo into a Fender Princeton style amp by VSA, and into a Vox AC-15 style amp by Realtone; mic’d with Sennheiser e606 / e909 mics, into the Fireface. Bass (De Delevee) played through a Line6 HX Stomp modelling an Ampeg SVT into the IGS Volfram.

Only few effects were added on DAW level: Some Valhalla Vintage Verb on the guitar, a bit of reverb, EQ and compression on some parts.

“Svefn-g-englar” written by Jón Þór “Jónsi” Birgisson, Ágúst Ævar Gunnarsson, Georg Hólm and Kjartan Sveinsson
“Oxygène (Part IV)” written by Jean-Michel Jarre
“Love Will Tear Us Apart” written by Ian Curtis, Peter Hook, Stephen Morris and Bernard Sumner
“Kelly Watch The Stars” written by Jean-Benoît Dunckel and Nicolas Godin
“The Look” written by Joseph Mount

All cover songs © by their respective writers and publishers.
All the rest © 2023 TheGuacamoleXplosion.