What is the best AC Voltage step down converter?


I am considering buying a 220 volt SACD player from Japan. Can anyone recommend an excellent step down converter that converts 220 to 110 volts that can handle 50Hz without any humming or buzzing problems?
audiozen
Japan uses 100V 60Hz/50Hz. All Amps/Cd players are designed for both 60Hz and 50Hz. You can change the voltage from 100V to USA 115V by moving the Jumper inside.
If you want use a transformer the best ones are
Nisso NDF-1500U or Sanyo both made in Japan.
Nissyo NDF-1500U It can be purchsed from a Japanese store in New York for $200. I recommend this one 1500 Watts. Sanyo is same in power but bigger in size.