Generally yes. There are manufacturers (some Quad and Revox pieces) that allow you to simply switch from 240V to 110V. In most instances you will need a step up transformer, they are not expensive. See my previous post on this subject.
However, some manufacturers, Krell and ML come to mind, specifically engineer their equipment to operate on either 60Hz or 50Hz. If you try to use 240V/50Hz equipment in the USA it simply will not work. I found out the hard way when I took a Krell HTS from the USA to France. In the end I had to pay Krell, not cheap, to convert the processor from 110V/60Hz to 220V/50Hz.
The other factor to be conscious of is equipment running on AC synchronous motors, for example turntables. If you run this equipment at the right voltage but wrong frequency it will rotate at the wrong speed.
