Just out curiosity, what kind of noise?
Its almost not worth mentioning because the pre was clearly defective. Think of a tire with a slow air leak. Audible from the listening position 12 feet away with no music playing. Audible between notes while music is playing. Very, very loud.
Sounds like it may be too much gain. In X4 mode, Freya S adds 12 dB of gain to your chain. If your stereo amp has high gain, and/or you have sensitive speakers, this can easily result in loud audible hiss. For example, when I run Freya S in X4 mode into Vali 2 on high gain, I get the kind of hiss you describe. Flip Vali 2 into low gain, no hiss. Just a heads up in case your replacement unit doesn't fix it.
No, it wasn't gain. Nexus 4X is 12 db gain and so is tube mode on the Freya+. The Freya+ is extremely quiet in my system. My headphone amp has 14db gain in preamp mode and again I have to put my ear to the tweeter to hear hiss. What the defective S put out was more like broadband white noise. Clearly audible through even my midrange drivers.
Tried a quick search for the diff between Freya S and +, was taken here:
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