XLR or single ended cables and why?

rats:[Quote]In the case of mono amps with single ended inputs they will share the same circuit ground, they are connected together at the single ended source, ie. pre-amp.[Quote]Steve, you missed the point. The right channel circuit will contain only the right channel interconnect and right channel amplifier. The current in the ground wire of the right channel interconnect will be equal in magnitude to the current in the right channel positive wire of the same interconnect, just in opposite phase. The same would be true for the left channel, so the electrical balance condition is maintained, just like in fully-balanced systems.

The question here isn't whether Andrewdoan should buy components with balanced circuits, since he already owns them. Anyway, in home audio this choice is rarely about reducing overt noise levels. For a combination of reasons -- running true-balanced is capable of reducing not only induced noise, but also self-generated noise, and in some cases distortion too -- the pertinent point is that the sound of the music might be improved by using balanced connections when running balanced gear, even if you never hear the result as being 'noise-reduction' per se. One of those reasons is that internally-balanced gear typically subjects unbalanced input signals to an additional circuit stage in order to convert them to balanced for processing, and this extra input stage is bypassed when using a balanced connection. (Conversely, gear that isn't internally balanced, but merely has XLR jacks wired in series with its RCA jacks for the sake of convenience, will often sound better with single-ended connections, which dispense with the extra jacks, wiring and solder joints at this small-signal juncture). So the answer to the question at the top is that there is no one right answer, it depends on the gear -- and with gear that was designed to make full use of a balanced connection, it makes sense to try one.

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