Dear @andyhifiman : " one of three possible all tube phono preamps..."
well, only the Rea and VAC are all tube phono stages. Been all tube designs means too that the cartridge signal must pass through many gain stages, around 4-5 in the REA and at least 6 stages in the VAC. At each stage the cartridge siggnal is degraded.
Both tube designs looks as good designs and good quality execution with good choice in passive parts. Btw, I don’t like tubes running a cartridge signal but this is me.
Now, you already own an average digital/analog control center that has as a " side line " facilities to handled cartridges. It does not matters which stand alone unit you will buy ( tube, hybrid or SS. ) the cartridge signal must goes through the C48 line stage and the quality level of the cartridge signal certainly will not be of the higher level of the stand alone phono stage but nothing more than the quality level in that C48 that ( sorry to say it. ) is just average. So do it you a favor and don’t " spend " good money where that money will be a " spend " and not a true quality level investment for your cartridge signal reproduction. Is up to you, it’s your money.
Regards and enjoy the MUSIC NOT DISTORTIONS,
R.