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Midi retrofit and feature extension for Roland Juno-6 and Juno-60

Description | Features | User Manual | Installation Manual | Manufacturing | Order online  | FAQ


The Juno-66 is an upgrade for Roland Juno-6 and Juno-60 synthesizers. It turns your Juno into a powerful Juno-66 synthesizer with midi and a lot of additional features.

Main features

  • Midi in- and output. Can output key presses, arpeggiator, Powerarp and chord memory.
  • Additional play modes: Polyphonic, Duophonic, Three-Voice, Two Monophonic modes, Chord Memory and Polychord. The Mono- and Duophonic modes feature adjustable fatness
  • Portamento for all play modes with adjustable speed and behaviour
  • Powerarp: A powerful sequencer that includes breaks and note lengths and can be triggered by the arp clock, trigger, midi clock or midi trigger. Features various direction, transpose and random modes.
  • Two additional filter LFOs: A triangular LFO with a frequency of up to 2.2kHz and a S/H style LFO with various clock sources.
  • A second ADSR for the filter.
  • Detuning. Turns your Juno into an organic analogue synth.
  • Alternative tunings: Select from a range of non-equal tempered tunings or upload a custom scale.
  • Midi filter, pitch bend, arp and portamento control.
  • Settings via an internal configuration menu or external midi controller.
  • Extra features accessible using the existing Juno controls
  • Comes with sticker overlays and all necessary parts
  • For a complete list of features please refer to the user manual.


Some features in more detail

Play modes

The Juno-66 adds additional play modes to the existing 6-voice polyphonic mode.
The Duophonic mode layers 3 oscillators for each voice and slightly detunes them. The result is a fatter sound, often called supersaw or supersquare. The amount of fatness can be adjusted.
The two Monophonic modes layer all six oscillators to create an even thicker sound. The fatness is adjustable. You can also select between two envelope retrigger behaviours.
Chord Memory lets you define a chord of your choice with up to six notes. You can then play and transpose it using the keyboard.
Polychord lets you assign an individual chord to each key of the keyboard. You can play the chords using the keyboard.



The Powerarp is a built in sequencer. A new sequence can be quickly entered and can also include breaks and different note lengths. The sequencer can then be triggered by various clock sources. The sequence can be transposed using the keyboard and shifted forth and back in time.
Forward, backward, forward-backward and three different random modes can be selected and the sequence automatically transposed over two octaves.
An external trigger, the internal arp clock, midi note trigger and midi clock are possible trigger sources. A divider for the midi clock can be set and adjusted in real time without losing sync.


A polyphonic portamento that works in all play modes including chord memory and Polychord!
You can adjust the speed and two preset speeds are directly accessible via a switch on the synth.
The portamento is linear on a musical scale and you can select between constant time or constant speed behaviour.
A special algorithm makes sure that even in Polychord mode the portamento sounds natural.


User manual

Original manual by Tubbutec

Juno-66 User Manual v1.29

There is now a great user manual remix by Sunshine Jones. The original manual can be found below as well
Juno-66 user manual by Sunshine Jones v 1.25 (website link)(backup link)


Installation manual

If you do not want to install the mod yourself contact us or find a synth technician in your area – they will be happy to do it.

Juno-66 is a replacement for the original Juno-6/60 processor. This processor needs to be de-soldered and replaced with a socket. The socket can then be used for the Juno-66 – or if you like to revert the mod for the original processor.
To install the midi sockets you need to drill a few holes in the back of your synthesizer. For the Juno-60 a replacement panel for the DCB connector is offered and no drilling is needed. If you want to have midi to filter and pitch bend control a few resistors need to be soldered. All necessary parts are included in the kit.

Please read this disclaimer before installing the mod.

A detailed installation manual can be found here:
Juno-66 Installation Manual

There is also a video installation tutorial by Vintage Synthesizer Solutions



The Juno-66 is designed an manufactured in Germany.
Only lead free components and solder are used.

Order online

Juno-66 can be ordered online in our shop. We ship from Germany and offer various shipping methods.


  • 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. An exception is the key transpose button which is used to access many of the new features. For most cases a work-around for the key transpose functionality exists
  • Q: Does this have midi controlled pitch bend?
  • A: Yes.
  • Q: Is the Juno 60’s DCB interface still working?
  • A: No, it is not. You can however always replace the Juno-66 with the original CPU to completely restore DCB. (But no Idea why you would want that 😉
  • Q: Can I still save the Juno-60 patches?
  • A: Yes of course. Juno-66 parameters however are not saved in a patch due to technical reasons.
  • Q: Is the tape interface still working?
  • A: Yes
  • Q: Do I get midi control of parameters like attack, decay, resonance,..etc
  • A: No, the mod does not have access to these

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


“last couple days i’ve been just bashing those fat unison bass sounds from juno-6. damn. poor man’s jupiter 8. 🙂 when modulating pulse width by env, it can sound almost like sync. and that’s what i really like.” -Customer via email

“Managed to install the Juno-66 in about 2 and a half hours, most of that taken up by desoldering the original cpu. So far it works flawlessly, and I’m quite clumsy with a soldering iron!
I’m seriously impressed. As far as I’m concerned it’s a work of genius, incorporating so many interesting and contemporary features into a 33 year old interface. I’ve never come across such a good quality and good value synth mod. Brilliant!
Juno-66 mod [..] has turned my quite battered old Juno 6 into a versatile monster. Never again will this 80s synth-pop classic be called limited. I’ve just spent an hour or so jamming away and I still feel I’ve only just scratched the surface.” -Customer via email

“Hi, Juno-66 is now installed and it’s awesome!” -Customer via email

“Recently installed [Juno-66] and I must say it has been an incredible thing for me. Not only is the midi implementation really great with solid timing, but it’s also a fantastic composition tool. Today I was sending the polychord notes through my Roland A880 and creating entire songs out of it with other gear. Using polychord with an MPC is especially fun. each pad triggering a chord, it’s a joyous thing!” -Customer via email

I just got my Juno 60 back from my tech, who installed the Juno 66 mod for me. I’ve been up all night playing with it, and every time I try a new feature I am amazed by how much better it is now than it was before. The Juno 60 has always been a superb instrument, and I will be honest: I was nervous that your mod would change the synth in a way that was not desirable. I was afraid that, despite all the new features, somehow the magic of the original instrument would be lost.
Well after several hours of playing, I see now that is not the case. You have somehow managed to make a perfect instrument even better than I thought possible, and so I just wanted to say thank you for what you have done. –Kenneth Gregory Bressler