The DAC output is 5.8 volts ... with the XLR . RCA DAC output is 2.9 volts. Am I losing any quality using the RCA.
You're losing 6 dB of s/n, which may not matter in your system.
Inputs can usually handle some voltage overload without damage, especially if that overload is < 20V. It's the output levels that can overload the amplifier, and speakers.
In this case it sounds like your DAC is 0.2V less than the maximum input, so all should be well. Assuming you input 6.5 V, the signal would clip (distort), but so long as your integrated's volume control is down that will sound bad, but not damage anything.
@paqua123 I have an Audio Holo May KTE and had the same concerns when I bought it. I've used it directly into my RAAL Requisite VM-1a headphone amp with balanced connections and am also using it in a Holo Audio Serene KTE preamp the same way with zero problems. Everything sounds amazing! no overloads at all.