What is the next Phono Pre-Amp for me?

I've never heard your ARC, but have fairly recently had in two systems of my own a Vendetta ???, an Aragon 47K, a Welborne Labs Reveille, an AHT DM-P, and, last but not least, a Pentagon PS-3. I can't fairly compare the Pentagon with the AHT, since I built stepped attenuators into the AHT (literally built both into a new chassis), but compared to all the rest, the Pentagon wins hands down. There were two for sale on Audiogon the last time I looked. It's one to consider, IMHO.

i have the herron, and had considered the groove. while i have not heard the groove, it's rep is very respectable. i have enjoyed the herron tremendously. it is in a tubed system, and seems to have great synergy with the rest of the stuff. the groove and herron are both totaly lacking of contols (you must order specific boxes for different loads), which i appreciate, minimum interference with the signal. good luck and enjoy it.

An Aesthetix IO would be a very nice phono preamp to have.