240v VS. 120v

[Gus]

Are there benefits to using 240v Ballast?

[DrPhoton]

Theres no efficiency differences, just the potencial to add more lights on a single breaker.

Regards Electrician.

[OzBud]

Here in Aus our standard power from the wall is 230-240V. I upgraded to a 400V digital ballast this grow from a 240V magnetic. Better light output frequency and enhanced spectrum output as well.

[DrPhoton]

The frequency is really dictated by the ballast design, many ballasts run at high frequency but some run at a lower frequency because they believe that it improves effeciency. The increased voltage really helps with efficiency only, i cant really see it improving spectrum because that is mostly dictated by the chemistry of the bulb. Though im not completely sure, got any readable material on this ?.
I have read that you do get increased light output of up to 10% with the same power draw from a typical bulb.

Regarding 120v vs 240v traditional ballasts, regardless of the voltage input, the ballast rectifys and modulates the input voltage to a standard reference. Theres no difference.