I have to laugh at idiots who buy a passive preamp, and then return it and give a one-star rating on Amazon because it doesn't "amplify" the signal. They apparently did not bother to figure out what passive vs active preamplifiers are, and cannot conceive that the prefix "pre" means before. And of course, anyone with a basic understanding or component audio knows that preamplifiers are located before (-pre) the amplifier in the signal chain, and do not necessarily amplify the signal- but rather they do add one or more "features" that can include a volume control, EQ/Tone controls, source switching, and even adding some "gain" for phono or other low-output sources.
The Douk/Nobsound XLR/RCA passive preamplifier seems to be sold around the world and targeted at people with active loudspeakers. No obvious bad reputation like many cheap ChiFi DACs and amps. Higher quality XLR passives start at $400-$500 (such as Khozmo, Axiom and Goldpoint), and go up to thousands of dollars each. I would not hesitate to buy a Douk/Nobsound unit if I needed one - especially from Amazon, where returns are easy.
Superbest AudioFriends.org did a comparison of the Goldpoint and the Nobsound and came to this conclusion:
View attachment 52852
View attachment 52853