XLR or single ended cables and why?

I hope the following issue will not lead to another subject: We agree on if using XLR connections with fully balanced circuit there is an increase in sound pressure level abt 6 db. If I use 4 ohm speakers, then according to spec, my amp will operate at 400 watt. With 6 db increase in SPL by using XLR connections, would my amp operate at 400 watts x2 x2 = 1600 watts per channel. Keep in mind abt the fact that every increase of 3db in SLP requires double in wattage to produce such 3 db increment. Simple math but does not sounds logical. Any thoughts?

Andrew: The SPL is determined by the volume control setting. (We needn't go into the subject of dB's, watts and ohms, but suffice to say that it's not as you suppose.) Anyway, don't worry about any of this -- everything will behave as it did, except that you may find your preferred volume setting to be a couple clicks lower.

Very good Serus, thanks!

steve

Andrew, no, no one agrees with that statement. The designer is free to apply any amount of gain to any particuliar input, he could just as well cut the gain in the xlr input by some amount compared to the rca input.

steve

I have not read the whole thread as it is a little long, so I hope I am not repeating what's been said. I recently attached balanced cables to my sim pre to sim power amp, and have to say the difference is tremendous. I plan on getting a balanced phono preamp now.