Modysix logo

Midi retrofit and feature extension for Polysix and Poly-61

Please note

The Modysix has been replaced by the ModyPoly.

Description | Features | User Manual | Installation Manual | Manufacturing | Order online | Poly-61 notes | FAQ | Quotes


The Modysix is an upgrade for the Korg Polysix and Poly-61 synthesizer and features various additional play modes, a free definable arpeggiator, midi in/out, a sustain pedal input and various other features.

Main features

  • Midi in + Midi out
  • Sustain Pedal input
  • Additional play modes: 2 Voice, 3 Voice, Polychord, extended unison mode
  • New arpeggiator / sequencer mode: Powerarp
  • All functions are easily accessible via buttons: suitable for live use
  • Midi controls arpeggiator clock, triggers the arp, filter, [NEW] pitch bend and more
  • Midi output of arpeggiator, chords and powerarp sequences or simple keypresses
  • S/H LFO for filter,  [NEW] triangular LFO for filter
  • Midi channels and various other options can be configured without external tools
  • Very easy to install, no soldering required (a bit of soldering if you want midi controlled filter and pitch bend)
  • High quality midi sockets and sustain pedal jack
  • For a complete list of features please refer to the user manual.
final promo web

Some features in more detail

2 voice and 3 voice

While the original Polysix only features 6-voice polyphonic, unison and chord memory, this mod adds additional play modes.2-voice and 3-voice polyphonic modes are tradeoffs between the maximum fatness of the unison and the maximum number of voices of the polyphonic mode. (Polysix only)


Polychord lets you assign a chord consisting of up to 6 notes to any key of the keyboard. This can be done very quickly and is very suitable for playing live. Of course you can combine this feature with the normal arpeggiator or the powerarp (see below). This makes it possible to have a sequenced chord progression in the matter of seconds.

extended unsion mode

The unison mode on the Polysix is basically a monophonic mode, but lacking almost all of the features that most monophonic synths have.The extended unison mode this modification offers changes that.
– legato mode (no envelope retrigger when playing legato)
– key priority up / down / last
(Poly-61 users see Poly-61 notes)



Powerarp is a feature best described as a sequencer or a custom arpeggiator.
You can define a sequence of up to 128 notes, which are then triggered by the arpeggiator clock. Up, down, updown and three different random modes are just a few ways to replay this sequence. You can use this with all play modes including Chord and Polychord, which means you can define complex chord progressions and replay them using the arpeggiator, an external trigger or using midi. You can also add breaks into the sequence which allows rhythmic arpeggiator sequences.


User manual

A complete user manual for the Tubbutec Modysix mod can be found as pdf here:
Modysix User Manual 1.4 for Polysix and Poly-61
Modysix User Manual 1.4 for Mono/Poly

For pre 1.4 version see Modysix User Manual 1.3


Installation manual

Installation of the Modysix is very simple. It is a direct replacement for the “Voice assigner” processor of the Polysix and Poly-61. No soldering is required here. To install the midi and sustain sockets you have to drill three holes in the back of your synthesizer and if you want the optional midi to filter control you have to solder one cable.

Please read this disclaimer before installing the mod.

An installation manual can be found here:
Modysix Installation Manual for Korg Polysix
Modysix Installation Manual for Korg Poly-61Modysix Installation Manual for Korg Mono/Poly



The Modysix is hand assembled and manufactured in our lab and the PCB is produced in Germany.
Only lead free components and solder are used.

Order online

Modysix can be ordered online here. We ship from Germany with fixed shipping costs worldwide. If you want us to install the mod for you please contact us.

Tubbutec Modysix

Midi retrofit and feature extension for Polysix and Poly-61.

Fully assembled retrofit with high quality midi and sustain sockets.
Also includes a stencil for drilling the holes and a sticker for labeling.

Price: 167€ + 5.60€ shipping 1

Order at Tubbutec Shop

final promo web

Tubbutec Modysix installed by us

Midi retrofit and feature extension for Polysix and Poly-61.

We install the Modysix for you. We are based in Berlin and you can either bring or send us your Polysix.

Price: 200€ 1

Contact us

Polysix Push button replacement

A lot of Polysix’s I worked with had worn or even broken push buttons. As the Modysix mod makes use of five Polysix buttons (POLY, UNI, CHORD, HOLD, ARP), the workflow will also be dependent on the quality of these. If your buttons are sticky or very hard to push, I recommend replacing them.

Replacing is fairly easy but requires some soldering. Multiple how-to’s are available in the net.

Replacement buttons can be ordered in the Tubbutec Shop

Price: 0.35€ / piece 1


Poly-61 notes

The Modysix works identically for the Polysix and the Poly-61, however due to the Poly-61 beeing DCO based there is no detuning between the six voices. For this reason it did not make sense for Korg to implement a unison mode into the Poly-61 and consequently it does not have a unison button.

As a result it is not possible to select unison, 2 voice and 3 voice mode by using the synthesizer’s interface. Even though it does not make sense to use 2 voice and 3 voice modes with a DCO based synthesizer (you just get less voices, but not the advantage of a ‘fatter’ sound), the extended unison mode offered by the Modysix might be interesting for some users for its emulation of classic monophonic synthesizers.

There are two ways to still use the unison mode with a Korg Poly-61:
– Select unison play mode by using midi (See the manual for how to do this)
– Install a unison button (and led). See manual here.


Photos by Krunwerke


  • Q: Do you lose any features by installing the mod ?
  • A: No, great care has been taken to maintain and emulate the behaviour of the original synths. All added features are additional to the existing ones.
  • Q: I know some electronics and I want more features!
  • A: Check out the Mod-Modysix post in our blog. There are some instructions for advanced users who can’t get enough of their Modysix
  • Q: Does this have midi controlled pitch bend?
  • A: Pitch bend is not an official feature of the Modysix, you can however install it granted you know a little bit about electronics. See this blog post.

If you have any questions, do not hesitate to contact us.


Für den Preis ist [Modysix] sicher die beste Erweiterung, die man dem Polysix schenken kann.
Translation: For the given price [Modysix] is certainly the best extension one can give the Polysix. [Synthmag #46, Sept/2014]

Wer einen Polysix hat und ihn liebt, sollte mindestens über Modysix nicht nachdenken, sondern sofort einbauen.
Translation: Anyone who owns a Polysix and loves it should at least not think about the Modysix, but install it.[Synthmag #46, Sept/2014]

I’ve purchased the Modysix for my 61. Shipping was inredibly fast. The customer advisory service was quick and very helpful and most of all particularly fair in exposing the pros and cons of the product. Modysix costs more than one competitive product and less than another, but to my opinion it is worth every cent of its price. The built in features seem to be designed with regard to the musician’s actual needs. Grandpa 61 got its rejunenation and he now plays major leaque again, along with nowadways flagships, at least in my opinion and my ears. No desire for Andromeda or Prophet ’08 anymore.[Markus Hahn, Tubbutec Blog]

Alle Geräte aus! Nur den Polysix und gemütlich bei einer Tasse Tee einen kompletten Song schreiben _und_ programmieren.
Ich liebe es wenn man mit einem elektronischen Instrument so ‘privat’ arbeiten und dabei trotzdem voll ausholen kann.
Translation: All gear off! Writing _and_ programming a whole song cosily with Polysix only and a cup of tea.
I love it when one can work with an instrument in such a ‘private’ way still can go over the top
[Norman Hecht, Nachtzug (Polysix and Poly-61)]

All well installed, was extremely easy to do. From the manual I had already appreciated the thoughtfullness that went into this modification, and now that I can use it I can only say: what an amazing creative expansion of the great Polysix! That mega powerarp alone would be worth it already, blows all other synths away! Big thanks!![mail from customer]

… I highly recommend it. Reasonably priced and you can install it yourself with little technical knowledge. The midi alone is worth the price but you also get super cool sequencer features for the arp and more. The designer/seller was very friendly and helpful …[Electronaut Forum]

I’ve got the Modysix installed and running in my Polysix. Absolutely brilliant kit with a very easy and elegant install (the hardest part was drilling the holes). The Polychord and Powerarp features are my favorite features as I enjoy trigger based sequencing (ala SH-101 and JX-3P). This is going to expand the usefulness of the synth so much in my studio.[mail from customer]

All well installed, was extremely easy to do. From the manual I had already appreciated the thoughtfullness that went into this modification, and now that I can use it I can only say: what an amazing creative expansion of the great Polysix! That mega powerarp alone would be worth it already, blows all other synths away! Big thanks!![mail from customer]

1 Aufgrund des Kleinunternehmerstatus gem. § 19 UStG erheben wir keine Umsatzsteuer und weisen diese daher auch nicht aus.
Due to § 19 UStG no additional VAT is added, nor is it included.

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