Korg miniKORG 700S

Name: Korg miniKORG 700S
Brand: Korg

Two oscillators, a ring modulator, and a control panel that puts its sliders in front of the keys. Korg's second synth is still the weird one.

Overview

The miniKORG 700S is a 37-key monophonic analog synthesizer, built as the expanded follow-up to Korg's first mass-produced instrument. The original 700 carried a single oscillator. The 700S adds a second, and that one change is the whole story of the model. It turns a modest preset-friendly box into a real sound-design tool with duet and detune modes, ring modulation, and the thick, unstable mono tones that made the name "miniKorg" stick for fifty years.

The keyboard runs three octaves of full-sized keys. It is neither velocity nor pressure sensitive, which was normal for the period but matters if you plan to play it like a modern controller. The service documentation lists the scale switch as covering 32', 16', 8', 4', and 2' on the triangular waveform, with square and sawtooth available across seven octaves. Those are organ-style footages, and they show who Korg was aiming at: players coming off combo organs who wanted the synth sounds they were hearing on records without learning a new language first.

What makes the 700S genuinely strange is where the controls live. The performance sliders — Volume, Traveler, Attack, Percussion, Singing, Repeat, Vibrato Speed, Vibrato Depth, Portamento, Pitch — sit on a panel in front of the keys rather than above them, a layout that looks wrong in photographs and makes perfect sense the moment you play it. Your hands never leave the keyboard to shape a note. The "Instant Set" tabs handle the rest: Expand, Bright, Sustain, Bender, Repeat, Vibrato, Delay Vibrato, and Portamento/Glide. The manual is unusually direct about what these are for — Expand is described as a subdivision of the traveler circuit that produces brass, underwater, bubbling, and growl effects when combined with the traveler and Attack/Percussion group, while the Bender tab adds a slide to the front of each note for glissando and slur, and Repeat simulates flutter, trill, and mandolin-style triple picking. This is a synth designed around performance gestures, not around programming depth.

Two features need their own paragraph. The first is ring modulation. The repair documentation walks a technician through a Ring Modulation Adjustment using the Modulator 3 selector and a 10K Ring Balance trimmer, tuned until "every pitch" is out of tune. That is the sound - clangorous, metallic, inharmonic - and it is why the 700S turns up in the same conversations as the 800DV, which Sound on Sound (April 1998, p.270) described as essentially two 700S synthesizers in one. The second is Delay Vibrato, which applies vibrato with a slight delay after the note starts. It is a small thing, and it makes a mono line sound played rather than triggered.

The 700S measures 29.3 inches long, 11.0 inches wide, and 4.3 inches tall, and weighs 19.8 lbs. That is small enough to sit on top of an organ or a piano. It runs on 117V at 50/60 Hz and draws 15W. There are two adjustable rear legs for tilting the unit, a music rack, and a connection cord in the box. The output section gives you a choice of a high-impedance jack at 100KΩ or a low-impedance jack at 5KΩ. The manual is explicit that you pick the one that suits your amplifier, and getting that wrong is a common reason a working 700S sounds thin or noisy through a modern rig. There is also a headphone jack on the parts list, and a fuse in the rear compartment that the operating instructions warn must be replaced with an identical rating.

The front panel carries no MIDI, no patch memory, and no sequencer, so the 700S is a committed live instrument. Every sound is dialed in by hand and stays where you leave it until someone bumps a slider. Owners report that this is either the entire appeal or the entire problem, depending on what they wanted from it.

Service Notes and Condition

The 700S is old enough that condition is the whole ballgame. The parts list includes 2SA564S and 2SC828S transistors, a 2SK-30Y FET, TS-200011 ICs, carbon-film resistors, and a spread of tantalum and aluminum electrolytic capacitors, and every one of those is a wear item at this age. Slide potentiometers are the usual first casualty on any 700-series instrument. The mechanical parts list shows the panel is built around 30mm and 60mm slide VRs in a range of values, and a scratchy or dead Traveler slider will take the instrument's most characterful control offline. Tuning is a manual procedure, not a preset. The service documentation describes setting the Attack and Percussion slides to 8, switching all Instant Set tabs off, and adjusting the pitch slide. A separate calibration routine has you press C4 and trim the 50K Hi Pitch control, then press C1 and trim the 10K Lo Pitch control, repeating until both land at zero cents. Anyone buying one should assume it needs that procedure, and should not be surprised if the power supply needs attention first. The voltage adjustment section calls for checking the DC rails and confirming ripple stays below 10mV.

The good news is that the 700S is repairable in a way most later digital gear is not. It is discrete, it is through-hole, and the schematics and parts lists survive. A properly serviced example is a stable instrument. A neglected one is a project. That difference is the single biggest variable in what these sell for.

Market and Collectibility

Values for the 700S have firmed up considerably as the early-Korg story has been told and retold. Working, unserviced units change hands in the mid-hundreds to low four figures, while professionally overhauled examples command a clear premium. Listings for a fully serviced 700S have run around $1,800, with clean original examples typically asking $1,300 to $1,500. The spread between those numbers is almost entirely service history, and buyers who know these instruments will pay for documentation.

The 700S also has a lineage argument the original 700 cannot make. Sound on Sound (April 1998, p.268) noted that Vangelis and Kitaro both cut their teeth on a Korg 700, and that the 800DV is effectively a pair of 700S circuits in one chassis. That makes the 700S the cheapest legitimate route into the sound of Korg's first-generation monosynths. It is not a replica or a clone, but the actual circuit the more expensive and more famous instruments were built from. Collectors note that the 700S is also the more useful of the two original miniKorgs because of the second oscillator, and that the ring modulator gives it a sonic range the 700 does not have.

The interface is where it gets awkward. The 700S asks you to learn its logic, and the front-mounted slider layout that feels right to a player feels cryptic to a collector who wants to look at a synth and understand it. It is not a beginner's instrument and was never meant to be. At 19.8 lbs with a 15W draw and no internal speakers, it also needs an amplifier and a bit of space. The manual's note about choosing the right output impedance is not decorative.

For anyone building a representative collection of 1970s Japanese monosynths, the 700S is close to mandatory. It is the second chapter of Korg's synthesizer story and the direct ancestor of the 800DV. Buy one that has been serviced, budget for the sliders, and expect to spend an evening getting the tuning right.