@gene or
@PENG - stupid question but I cannot find an answer. I have an external DAC that can output 4V or 5V. Does it matter to the AV10 which I send the XLR input? I cannot find anything about it and Marantz tech support didn't know when I called them. I know 4V is generally the standard but there seem to be more and more DACs that output either 5V or have selectable 4/5V. I need one of you EE types explain it to me. Please?
How much voltage you need, depends on many things such as the gain of your preamp, power amp, your speaker sensitivity, impedance, and your listening habit (that is, contents, and how loud you listen to) and your seating distance.
Having said that, 4 V balanced output should be high enough for most (probably >95% of the people). The reason why balanced need 4 V, that is double that of unbalanced output, is mainly because many power amps lowered the gain by about 6 dB if balanced inputs are used. I am not sure why they do it, but my guess is that they want the amp output level to remain the same whether you use balanced or unbalanced inputs. It seems to me more and more power amps are no longer following that standard, for example, the newer ATI, Parasound amps seem to keep the same, or approximately the same gain whether you use their unbalanced or balanced inputs.
My two Marantz power amps do have 6 dB lower gain if the XLR inputs are used, but they are the old class AB type. Your Amp10 is class D and is a new model, so I am not sure if it also lowers the gain by 6 dB for the XLR inputs, my guess is that it will, as that seems to be the standard Marantz would follow. In any case, 4 V (XLR/balanced) should be more than enough unless you listen very loud, sit far from the speakers and the speakers have very low sensitivity. The amp10's spec says gain is 29 dB, without specifying whether that's for unbalanced or balanced, but even if they lower it to 23 dB for balanced inputs, you will still get 400 W into 8 ohms, or 800 W into 4 ohms because you will get 2X the voltage from the AV10's XLR output vs their RCA outputs. The amp10 is only rated 200 W 8 ohms, 400 W 4 ohms, so you have plenty of reserve for use with a DAC that can output 4 V balanced.
Also, keep in mind the pre out voltage is not going to be that high most of the time, in my case they rarely go over 0.5 V (actually much lower), that's because music signals are not test tones, they vary in magnitude from 0 to less than 1 V on average most of the time, only peak to high voltage occasionally, depending on the contents you play.
