My PA amp has balanced inputs (XLR and TRS jack). Much simpler!
I tried using one of those XLR-jack adapters once, on a mic input (I forget why the mic lead had a jack on the end, can't have been one of mine). The result: the transformer picked up masses of hum from a nearby power supply. Never again!
[complete change of subject] Graham, what ICs are you using in the front end?