Tobias: You don't need a bucking transformer at all. You can simply use a 220 - 240 volt transformer and separate the legs down to two 110 - 120 volt lines. Personally, i prefer to keep all of the equipment on one leg of the 220 line, but there are those that have split them and never run into problems. Many of these transformers can be run with multiple taps i.e. 110/120, 220/240, etc...
The spec's that you quoted as far as capacitance and "ultra isolation" are right on the money. The only other real factor is current capacity. This would be the rating in KVA's. If you have a 5 KVA ( 5000 watt ) transformer and are running it at 220 volts, you can use ohm's law to tell you how much current it can sustain. Divide 5000 by the input voltage ( 220 or 110, etc... ) and you'll arrive at how much current the transformer can pass. As mentioned in other threads about this topic, i recommend staying below 60% of the rated capacity of the transformer if possible. That is, if your entire system adds up to 2000 watts of draw, you should have a transformer capable of 3 KVA ( 3000 watts ) at the very minimum. A 3.5 KVA unit would be better and closer to the ratio i described. Obviously, a 5 KVA would provide even more headroom with the potential for an even lower noise floor due to less noise induced by the transformer itself.
Hope this helps. Sean
>
