Like several of the others my guess is that the hiss represents normal behavior for this particular design, and for many other phono stages as well. However as Lew indicated we don’t have enough information, or familiarity with the particular phono stage for that matter, to be able to say for sure.
I see that for low output moving coil cartridges the gain of the phono stage can be adjusted via internal switches between 50 db and 72 db. Assuming you are using an LOMC you might find that changing the gain from whatever it is set to (probably in the direction of reducing it by a modest amount) can help.
Also, as Steve (Williewonka) said, different phono stages differ significantly in their noise performance. Like Bill (Bpoletti) I have found my Herron VTPH-2 to be totally silent, even when listened to in LOMC mode with my Stax electrostatic headphones firing directly into my ears and with the volume control on the Stax amplifier at max (which is way higher than I would ever set it to while listening to music). But that has been a source of constant amazement to me, and I would not expect the majority of phono stages to be similar in that respect, at least those having active input stages as opposed to transformers.
... with the hiss there’s also a mild hum
That could be due to a ground loop issue between the phono stage and the preamp. As an experiment, try temporarily putting a cheater plug (a 3-prong to 2-prong adapter) on the power plug of either component, to defeat the safety ground connection. That would break a ground loop that may exist between those components.
Also when I disconnected the XLRs from the Whest & increased the volume on the phono stage input I could hear my CD transport playing.
Assuming you are referring to XLR cables on the output side of the Whest that sounds like crosstalk within your preamp. Normal (albeit non-ideal) behavior for many designs, which is likely to be exacerbated when the preamp’s input is left unconnected.
Regards,
-- Al
