Yamaha SK10 / SK20 / SK30 / SK50D

Yamaha SK10 Image

Yamaha SK-10

Yamaha's SK-series are combo-keyboards with synthesizer, organ, brass and string sections. The SK-10 was the first of the SK-series, released in 1979 - the SK-20, 30 and 50D followed in 1980, and the SK-15 in 1981, possibly as a replacement for the SK-10. The SK-10 is the only one in the series that does not incorporate a synth section, but has organ, brass and string sections that can all be played together for more interesting combinations. Very sturdy casing, 4-octave and fully polyphonic the features also include a leslie simulator, vibrato, attack and sustain rocker switches, a slider for 'brilliance' and a one-octave transpose switch. Not exactly feature-laden, but a lovely string synth sound. Interestingly, they are often referred to as 'analog', but in fact do have a digital section. Its organ has one of the early implementations of Yamaha's FM technology in a very limited form, concurrent with the GS-1/2 development platforms which eventually led to the DX series.

The ORGAN SECTION is available in all the SK series synthesizers. It offers a full range of stop levers from 1' to 16', percussion levers with adjustable decay, and controls for overall sustain, brilliance and decay. This gives you quite a lot to work with in the way of synthesis. The organ's sound is FM based and it sounds very B3 like. You can add a Vibrato and a noisy but good Tremolo to it. Its sound is all about the 70's era rock organ, especially with the Ensemble chorus effect in use. It also has a Leslie-speaker output around back.

The PRESET STRINGS section isn't very sophisticated and offers very limited editing capabilities. It is the string section though, that is worth aquiring this keyboard for. Very similar to the best of the string synths, (such as the Arp Solina/Omni or the Logan String Machine) it has a sound reminiscent of the opening of 'Oxygene' (J-M Jarre) or the lead line from 'Love Will Tear Us Apart' (Joy Division).

Yamaha SK-20 Image

Yamaha SK-20

The SK20 adds the POLY-SYNTH SECTION: a 7-note polyphonic synthesizer with basic filter, pitch, envelope, and portamento controls. It features two (detuneable) oscillators per voice so it's good for thick pads. It lacks any bite whatsoever and, even in normal attack mode, has way too slow an envelope to be used for any bass or percussion sounds. But, the pads and strings you can get certainly shine and glitter like Bowie a-la Ziggy Stardust (especially when layered with the Strings section). It's like a good entry-level synthesizer. Basic and simple LFO, filters and ADSR envelopes. It has a built-in sustain and the Tremolo and Ensemble chorus effect also apply to this section.

Yamaha SK30 Image

Yamaha SK-30

The SK30 (weighing in at over 90 lbs.) and SK50D also feature a SOLO SYNTHESIZER SECTION which is a single VCO driven mono-synth similar to a Roland SH-101. It has basic pitch, waveform, filter, volume, envelope generator and portamento functions. Its resonant filter isn't great and can't be driven into self-oscillation. The keyboard's after-touch can control the vibrato, tremolo, and brilliance effects. You can effectively play leads in the solo section while simultaneously playing chords in the string, organ or poly-synth sections.

Yamaha SK50D Image

Yamaha SK-50D

The SK50D adds the Bass section as well as an additional second keyboard stacked above the other! The BASS SECTION provides an independent set of tone generators and controls for a deep, rich organ bass sound. It has its own set of stop levers, as well as sustain and brilliance controls.

All the different sections of the SK synths can be layered and stacked via the slider bars. You use the slider bars as a mixer to set the individual volume for each section. All sections have their own separate audio outs (though a mix out is also available). A great thing for live performances is the split keyboard mode. That way you can have, for example, a very nice, punchy bass sound from the synth section and a lead sound coming from the organ or solo sections. Although it has no patch memory, there are push buttons for instantaneous selection of organ, poly-synth and string preset sounds; there are three presets in each section. It also, has no arpeggiator or sequencer, and lacks MIDI. But it's cheap, easy to use, has a nice sound, full 61-note keyboard, and classic wooden panels. The SK's have been used by The Constantines, DJ Logic, Sigur Ros, and Ben Wa.

Lookup Yamaha SK10 / SK20 / SK30 / SK50D Prices

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Are you looking to buy or sell a Yamaha SK10 / SK20 / SK30 / SK50D? Post an ad in Gear For Sale or a request in Gear Wanted. For spare parts and repair services check out Gear Services & Other Goods. Our forums also has a Buyer’s Guide section where you can ask for advice on buying synthesizers.

53 Visitor comments
geoff francis
July 3, 2010 @ 10:58 pm
I have been searching for a good yamaha synth for years now and just purchased a sk50d from the classifieds. the organ sounds are awesome. this is completely ridicules for its time because you get cs-80 sounding strings and poly synth sounds with the most outrageous base mono synth and a lead synth that has after touch. and separate volumes and the ability to layer multiple voices.there are many inputs on the back for controls and separate outputs for each section and leslie out although it has a really good sounding leslie sim that has a realistic speed control. mine doesn't have any tuning problems ether. I keep blowing up speakers with the synth and synth bass sounds which is truly inspiring, I'm in love! you could easily record a good album with this one instrument similar to the cs-80 or gx-1 becausetips from fellow sk pilots? does anybody know how many ocilators/tone generators it has???this is an awesome sthh for sure get them whie you can if you can peace.
October 3, 2009 @ 6:00 pm
It's basic in terms of features, but incredible because it sounds so good! It has so "edgy" (in a good 70's way) sounding oscillator that becomes very awesome when playing octave-unison etc. I wish I could trigger it via MIDI (or just play better).
I like the fact, that the SK20 is actually 3 in 1 instrument. You can get unique sound by layering the different sections.
One of the best features is the superb-sounding ensemble effect! That's where you got one very nice string machine here, and by applying the effect to the organ section you get lovely "organic" pads. The onboard rotary effect is also good.
You can have the saw and square wave together in the synth section by adjusting the slider in the middle. This resulting soundwave is nice and aggressive.
Despite the "too slow an attack envelope" I've certainly used this machine for basses too. Put some EHX effect pedals after the SK, and get some truly wonderful synthesizer stuff!
September 22, 2009 @ 8:24 pm
I've been using an SK-30 regularly for a couple years. After some initial repairs it became clear that it was quite a find. I LOVE being able to mix all 4 sections together. The solo synth section blows my mind, especially when mixed together with the organ or string sections with a touch of portamento. The SK-30 is a heavy beast. A versatile, solid, marvelous beast. My brother asked the keyboard player for the Constantines if he ever used one, and he had no idea what my brother was talking about.
Nate Krell
June 17, 2009 @ 4:59 pm
I toured Canada with an SK-20. Great, well built.
--> To anyone who says the organ doesn't sound like a B3: Use Preset 3, with Tremolo on Fast, and some percussive 'click.'
--> To anyone who says the strings [beep] : Make sure to use the Ensemble effect. Also try the slow attack and/or sustain. Ensemble is noisy, but no more than a Juno 6.
--> While the Ensemble is great for the strings, it kills the synth tone. Another hint for the Synth: The waveform/octave is set by a slider-switch, a bit like a stratocaster guitar. The strat originally had only THREE pickup switch positions, until players found they could "balance" the switch in-between, to get combinations of two sounds. The SK-20/30/50D can all do this. Leave the slider between the 8' Saw and the 16' Square. No more my-first-synth sounds.
June 15, 2009 @ 9:02 am
Hello everybody,

I'm trying to form a new live band. Except of my Fender Rhodes I am looking for a combo-keyboard just like the SK-20 to provide me some synth, some organ and some strings. Due to the fact that the Yamaha-SK synths are very hard to find: Does anybody know a fitting substitute?
THX, Henk
VSE Rating

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User Rating

Rated 4.35 (824 Votes)

  • Check Price
  • The link above will take you to an eBay search for this synth to see active listings. If you don't find it there, try looking in our forum marketplace or post a wanted classified.
  • Specifications
  • Polyphony - 7-voice polysynth and string + Full FM organ + monosynth
  • Oscillators - One VCO, two in polysynth section
  • LFO - One with Sine waveform only (leslie simulator - 2 speed)
  • Filter - Brilliance control, Resonant low-pass 12dB filter (non-self-oscillating)
  • Envelopes - rocker switches for attack and sustain
  • Effects - Vibrato, Tremolo and Ensemble effects for the organ and poly synth string sections.
  • Keyboard - 61 keys (122 keys on SK-50D)
  • Memory - No user memory. 3-preset patches per section.
  • Control - CV-Gate IN/OUT
  • Date Produced - 1979-1980
  • Resources & Credits
  • Images from Audio Playground Synthesizer Museum,
    and Andrew Heaney.

    Additional information provided by DAC Crowell, Mikael Bengtsson, Michael Bonanno, Andrew Heaney and Patrick Coleff.

    Reviewed November 2007.

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