Thanks to Mac128 for refreshing all of our memories on this, and for providing a link to Apple's own information on this topic. In the US, none of the classic Macs shipped with dual-voltage analog boards. Assuming that your source of analog boards is not too far from your home in Ohio, they should all be 110V units. If, by some chain of events, you end up with a 220V unit, you won't damage anything by operating it with 110V. But it also won't function, either.