Go Sim Lim Square..go up escalator 2nd floor, turn right, there's AVit Electronics and if you go further right after this shop, there is like a DIY kind of shop..both do sell transformers. But if you are using transformer, please be cautious taped the power cord to the transformer as well as to the appliance such as your amp...lest your maid or mother in law, may accidentally just plugged in your imported toy and experienced a blackout or a call to the fire dept...