voltage transformer and tube gear

I have tube pre and considering buying a tube amp. I will be posted overseas to a 220v/50hz destination soon and will bring along my toys. Could anyone tell me whether using a step up transformer is all I need or is there more to it than that. I know in the case of turntable we have to be concerned about the difference in hz (50hzvs60hz)but what about amp and pre.
A step up transformer for the preamp could be considered, because the pre is generally low on powerconsumption. The poweramp however is an entirely different story and you would probably need quite a hefty unit to do the job properly without serious losses in dynamics. I'd rather suggest, you contact your dealer or the manufacturer direcly on how to change the voltage for your units. More often than not that can be done quite easily by someone qualified to do the job. Hope this helps you on a bit.
I truly apprecaite your helfful advice. If I were to buy a 50watts tube, what would be the appropriate size for the transformer? Does this apply to both tube and solid state?
Thanks again
Most amps have a power consumption rating. Class A amps will draw a steady current until forced to A/B. Class A/B amps fluctuate draw on demand. Some, like a Carver Lightstar (300 wpc) can draw up to 15 amps at peak, however unlikely. As a guideline:

50 wpc stereo = 300 VA (watts) input, roughly 3 amps,
100 wpc = 500 VA, roughly 5 amps

As a general rule a transformer should be double the VA of the demand but 2 KVA would be the minimum I would suggest, even for a small amp. Honest three KVA, but not all, would allow 15 amps of most household outlets and weigh about 75 lbs. Wired for balanced AC, derate by half. No transformer will convert Hz but that shouldn't be a probelem for pre/amps. It could be a problem for a CDP or DAC but most of those can be either 50/60 Hz.

I use a 120 lb,5 KVA tranny for 20 amp balanced.
You could use an autotransformer

The power transformers of the audio equipment need to be rated for 50/60 hertz. Most are today.

Transformer calculator
Wow!!! There is so much information .I really appreciate all of you for taking time to enlighten me on the subject.
Happy listening
Depending on what country you are working in and "who" your sponsor is, the country that you represent overseas will usaully be able to provide transformers or offer them for sale in the stores they provide, for example, if you are in the military, are DOD or work for NATO you will be able get transformers normally rated from 75 up to 3000 watts in the onbase stores.

Basically you will need a transformer and powering a CD palyer, preamp and amplifier are generally no problem. Turntables will need an outboard speed controlled power supply to work with your current turntable, they do have an oscillator, which is the only way you can change frequency on the fly by the normal user. They are expensive, but VPI, Clearaudio and a few others sell these. There is always going back to the vendor and asking what the costs would be for a 220/50hz motor and compare that with the outboard speed controllers.

On the other hand if you are sponsored by a company and will be here living on the local economies, they also sell transformers, might be harder to find, and you will be able to do the same thing.

I used a Soundscraftsman A5001 for years, rated at 1000 watts per channel with a 2000 watt transformer without any issues. There are two advantages to running a transformer, one is that with tube gear sensitive to RFI, the transformer eliminates any from entering your tube equipment plugged into the transformer, and the other advantage, is that the rating of transformer means and this depends on the construction of the transformer, is that total wattage rating is available to supply to your equipment at any time. This also means eating more electricity, and that can be expensive if you forget to turn off your transformer and equipment. I tested a few transformers that only used 10 watts at static use and no load and with a load they fluctuate to the amount of watts required by the equipment. From my experience, normally, when you turn it on, it surges and will store the amount of rated watts and will not need to draw much more unless it is used and the equipment starts sucking the power out of it.

Good luck,
I should have mentioned that transformers can have an audible hum due to internal and external factors, but espescially when overworked. One might be quiet in one spot and be noisy somewhere else. Good grounding helps. Ideally, they should be in another unoccupied room.

The GE, Q-type, step down, general purpose, single phase, isolation (Ebay keywords) tranny of mine is dead quiet, but it's epoxy potted also. A shielded unit is also preferred but that can be tough to find out.
Many transformers have a pair of primary windings. You use them in parallel for 120V, in series for 220/240. A lot of consumer gear allows this to be selected with jumpers.
Surely you need a step-down (rather than step-up) transformer to go from 220V mains to 120V appliance? If so, the PS Audio 300 has good reviews and you can also vary the frequency - I am condidering one for a CD player