If you like your system as is, I would not sell it. The loss is simply too great. Also I would not use an ordinary stepdown transformer, although that would be the cheapest solution. They generally screw up the dynamics of your musical renderings. Of course if you can rewire the transformers in your units, fine..that would be the easiest way. Otherwise, I'd rather invest in a PS Audio 300,US version, which you can buy used even here on Audiogon. There is an internal switch, which you can set to 220VAC and it will happily feed your gear at a 120...and you even have the advantage of clean and pristine power. You need NOT to worry about the frequency of the powerline at Singapore, as Sqjudge has suggested, because the PS Audio takes care of that. You will kill two birds with ones stone: You need not worry about power and your system will sound better. You can inform yourself about the PS Audio products at www.psaudio.com .
Cheers and regards,