great points from atmasphereAs atmasphere says:
i would only add that phono stage gain is the most precious of all gains since it magnifies the original and smallest signal
so having more gain than you need at this critical point often introduces noise or distortion that can otherwise be avoided if gain were to be optimized to the cartridge output and the rest of system
to have a lot of excess gain at the phono stage, then to use a passive or other attenuator to reduce it down significantly is, imho, a very unproductive exercise
Of these, its 4) that is the least understood, even by preamp designers.
Like you, here is where it gets confusing to me, but at least I’m trying to think your question out for myself.
The Aric Audio Transcend MM Phono Stage has a - Variable output level control for source matching.
http://aricaudio.com/products.php?product=MM12AX7#desc
Could this Variable output level control for source matching be used as a volume control? On is it just a gain pot only?
Thanks