Using the terms "yamaha montage 220v" in a search engine yielded the following as the first result:

https://www.yamahasynth.com/forum/110-220-volts-automatic-or-n%D0%BEt

The prevailing wisdom is to check with your local sales rep.

If it were me, I would consider using a UPS which accepts 220-ishV as an input and outputs 110V. This would kill two birds: allow the Montage to survive a power outage and also handle the conversion. Of course some form of outlet connector conversion would also be needed as these vary. I have such a converter that only cost a $1 and has worked well for international travel.

Thanks, what I wanted was, avoid carrying the converter from 220v to 110v everywhere 🙁

Yamaha Montage, World Class Synth, Not Multivoltage?..:(

Hello thomas - I'm amazed you haven't had an instant definitive answer from Yamaha ... however, I wouldn't risk plugging 220v into a 110v machine, as the most likely result would be having to fork out another $4000. Buy a transformer - pop it in the box with the Montage - it won't make much difference to the overall weight.

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Paraphrase from Yamaha support:

I have received a response from Yamaha. The response is that the Montage includes a universal AC power supply which does support 240V. The requirement would be to obtain an IEC (IEC cables have dash numbers - and "IEC" is often used as shorthand for the trapezoid type connector on the back of PC power supplies and also on the back of the Montage) cable that fits the outlets in the region if not the US 3-prong type. For obtaining one, Yamaha support suggested finding a local authorized Yamaha dealer or calling one in (ordering) ahead of time and shipping it. As we all know in the US - most computer outlet stores have these types of cables if we needed a replacement for the Yamaha supplied one - so I'm sure you could also find one at a Bestbuy, Microcenter, or Fry's equivalent in Australia.

The support number is 714-522-9000 (option 3, open 8:30A-5P PST M-F) for US support which would land you in the same group who answered this question.

For people in other regions, I could see more questions on the limits/modes (voltages, phase count, etc) of the power supply not covered in the above information.

Personally, I wish this sort of information was part of the specifications in the owner's manual. This is a fairly basic specification not to have documented. I would suggest a revision release to include this and a Montage FAQ update to include this information in the interim.

It does appear a transformer is not required to convert the voltage.

so,
It's official?

All the yamaha montage sold in the world are multivoltage,
Independent where they were purchased and the tag they have attached, 110v or 240v

All are multivoltage and can be plugged anywhere in the world without adapters.

I understood this

Please confirm again

Yamaha's internal business policy is to obfuscate the power-supply's published specifications for montage. This is why the original advice was the call customer support. As a blanket statement I can say that montage's power supply is multi-voltage and should accept the local voltage of any region.

They do have a legitimate purpose for documenting the specifications this way.

Hello,...
What they are saying is that the yamaha montage 8 is multivoltage, no matter what the backplate says?

Are you sure ?????

Despite the double check and now your triple check - yes I'm sure. I left all sources so you are free to call or email customer service yourself. I encourage this if you are are left with any doubt.