I have an ancient outboard phono preamp...PS Audio II, which dates from the early 1980s, and was the original product of the firm. It consists of a single top quality circuit board, with top quality parts, inside an elcheapo folded aluminum shell with wooden ends. Who cares what it looks like as it is mounted out of sight. I think it cost about $275 (1980 dollars).
The circuit consists of complementary amps using very low noise transistors, and a passive RIAA equalization network between stages (instead of heavily equalized feedback). This was unique at the time. Does anyone use this approach now?
Anyway, I have yet to hear a better phono section.
PS Audio did come out with a later model, where the power supply was relocated to another box, but I don't know why because there was never a hum problem with the original model. They also evolved the design into a full preamp, with line level switching. When they jacked up the gain for MC pickups the results were not so hot. I used a transformer with mine, and it worked well.
