No need for a separate power supply for the Hagerman (Trumpet MC) wall wart. The circuit is designed around canceling noise with a wall wart.
I have a phono pre with a separate power supply and it gets noisy with MC carts. Not with the Hagerman. I turned the volume all the way up and was able to hear a subtle low frequency pulse. I pushed the Hagerman back 4" and it disappeared into a subtle hiss. I have a crowded rack so this is an achievement.
Load and gain is adjusted on the front. Soooooo much easier turning knobs than messing with dip switches.
Can’t afford the Herron? Try the Hagerman Trumpet MC. It seems to be at that level for about a hair over $1000.
It has a large, sweet, organic presentation. Excellent bass.