First of all, some nomenclature: a converter changes the voltage (and sometimes even the frequency) of electricity. An adapter just makes it possible for your plug to connect at all to the local socket; it doesn’t change any aspect of the juice you’re getting.
Throughout South-east Asia, you’ll typically find multi-standard sockets. That is, if you have a two-pin plug, like the Europlug or the standard German, French, or Italian plug, or the British “shaver” plug, or the standard American two-bladed plug, you can fit it in there. Well, not “fit”, but you jam it in there and wiggle it around and be careful not to pull it out, it’ll work. Some places even accept heavier-duty American grounded (two blades and a pin) plugs. The only thing you need an adapter for is those big British BS-1363 plugs and I can’t imagine what you’d be carrying that would have one. An electric chair?
Adapters: you don’t need them
The converter. Most of South-east Asia (maybe all) uses 220 volts, just like most places. If you’re American, you probably only use 220 for your clothes dryer, which I would recommend you leave at home anyway. Do you have to worry about this difference?
- No. Almost anything electronic will accept both 110 and 220. If you have something old, you should look on the case for a note that say either “110V” or “110V-220V”; only use the latter.
- Maybe. 110V resistance-heated devices — irons, teapots, steamers, that sort of thing — will “work” in 220V. In fact, they might work too well. They heat up faster and hotter with the higher voltage, so depending on how you feel about dying in a hotel mattress fire, you probably want to watch them carefully while you’ve got them plugged into the Asian mains.
- Yes. Anything with moving parts, motors, fans, will be sensitive to the voltage (and in some cases to the frequency). Check the case and the manual, but if in doubt, don’t use it. The exception is the fans on electronics (like laptops and video projectors); these are driven by the internal power-converter of the device and will work fine at 220V.
Converters: you don’t need them
Special note for Myanmar: all the foregoing is true, but it scarcely matters. Electricity is so unreliable in most of the Union, it’s barely worth bringing anything that has to be plugged in. If you happen to be in your hotel room while the power is on, go ahead and jack in, but if the power goes out again, unplug: there will be all kinds of weird surges when the power comes back on that will shorten the life of your device. Do not just leave things plugged in “in case” the power comes back on. The only exception might be a battery-charger that’s not part of the device, where you actually pull the battery out of the device and stick it in the charger; those are safe to leave in in the hopes of catch a little charge by luck.
Other than that, you probably don’t have to worry about this subject at all. Whatever you are bringing with you will probably just work.