I have a high end audio system, bought in the UK. I was wondering
whether a voltage transformer is sufficient to use it in the USA, or
will there be a problem with the 60hz vs 50hz.

   Thanks!

To clarify, you want to run the system from 110 volts but it is
designed for 240 volts only, so you want to hook up a transformer? As
long as you spec the transformer for power requirement, no problem at
all. Cheap too. Auto transformers can be even cheaper sometimes.

Not sure if step-up transformers are readily available in the States
but you can simply use a step-down transformer back to front, readily
available over here in UK. Suggest you go for a more expensive torroid
transformer because they are generally less noisy. Stray magnetics are
less too though not usually a problem.

Only slight consideration is that occasionally systems incorporate a
mains frequency notch filter in the audio path in the misbegotten
belief that it will remove residual hum whilst not affecting the
sound. Obviously this won?t work on 60Hz but it would be no loss --
and unlikely anyway.

Hopefully it?s not a valve system. Sometimes the PSU is designed to
filter out 100Hz (full wave rectified) but that?s pretty dumb too and
makes virtually no difference.

Regardless if it?s a transformer or switcher based PSU in the system,
it won?t mind 60Hz in the slightest. Slightly better in fact. But
before you do anything else, are you sure it can?t be run from 110
volts. Take off the lid and check if there are voltage selection links
inside (if not on the outside).

If I have interpreted your question incorrectly, please advise.

Best

You got it completely straight. I do not believe that the thing has a
voltage switching power supply. The only question about the
transformer is what power should it be rated for. That is, if it is
rated for 300W continuous, does it mean that it won't croak from
occasional spikes (in fact, I doubt that this will ever happen, but
one never knows...)?

 Anyway, thanks a lot!

Yea a 300 watt transformer will supply 300 watts continuously and you
are quite right that a bit of short duration overload is fine. Voltage
will drop a tad but things will cope. As with anything else though,
conservative rating is wise, so a 300 watt transformer running at 300
watts will get pretty hot. There might be a power requirement wattage
rating on the system, or VA, which you can use as a guide. VA is
similar to watts (if you don?t know), but to convert VA to watts in
your case add 20% or so and you should be fine. For a sound system
though most music, even on maximum volume, will average out to far
less than the output wattage rating.

Enjoy the States.

Best