Primare DAC 30

Sorry I don't understand your post at all, both outputs are 4.3V so what is the 2v output you are referring to in your post?

Jond:

Thanks for the reply!

The 2V is from my CD player directly, also from the RCA/single end of my OPPO 105. So, if I leave my volume setting unchanged in my preamp, DAC30 is as loud as my CD player or RCA output from OPPO 105, but far less loud than OPPO 105's XLR output, which is also 4.3V. So I am wondering if something is wrong with my unit.

According to online reviews your DAC is fully balanced, so it doesn’t make sense to me why the SE output voltage spec is the same as the balanced.
Maybe call the manufacturer or dealer.

@lowrider57  I double checked the manufacturers specs and they do list both outputs at 4.3V it seems odd to me also.