Gain versus volume

If I understand your question correctly: The "volume" knob on your preamp IS a "gain" control. Hence- There is no actual difference since the are both really amplifiers(one a pre-amplifier and the other a pre-pre-amplifier). As Mr V stated: The one you choose to increase your "gain" through can impact your signal greatly.

Having the ability to select gain on your phono preamp gives you the flexibility to match the gain of your vinyl rig with that of other sources feeding your preamp (e.g. a cd player) so that whether you are listening to vinyl or cd your preamp volume control will operate in the same region. Keep in mind that setting the phono preamp at the higher gain setting may introduce more residual noise from that device which will depend on the downstrean gain of your system. I assume that the Rhea is quiet regardless of the gain setting chosen.

Yes...my Rhea is very quiet. So as I understand this....gain and volume are both the "same"....correct?

Thanks for helping understand.

There's no difference between increasing gain at various points in your system. The goal is to have the various stages adjusted such that they all operate in their most linear ranges.

Agree with Onhwy1.

Your active linestage should operate centered at about 12-1:00 at moderate volume.