Herron VTPH-2A vs Rogers PA-2 Phono Preamplifier

The Herron has two two gain sections - the FET front-end used only by the MC circuits, and tubed gain stages used by both the MC and MM sections.  You are not just listening to a FET through the MC stage but in my experience MC carts sound best using a quality SUT through the MM stage on the Herron.

A different topic. To SUT or not to SUT. I had just edited my previous post to include mention of the type of circuit that you describe for the Herron. My own SilvaWeld SWH 550 phono stage is configured the same way. The FET drives essentially an MM phono stage when you are using an MC cartridge. Less interesting but more adaptable to a MM/MC switchable phono layout than is the cascode topology.

There is a Rogers unit for half the MSRP on USaudiomart.
https://www.usaudiomart.com/details/649709740-rogers-pa-1a-phono-preamp/
Its overall construction and performance are at minimum equal or "better" than the Herron. Interesting looks with the red paint and meters.

The Rogers also uses FET in the circuitry. Most everything on the market employs a similar topology.

Either an FET or a built-in SUT or an all-tube or hybrid cascode, in order to develop enough gain to suit a typical LOMC cartridge.  All of them work and can sound fine.

Nice write-up on tube rolling in the Herron.

Tube Rolling the Herron VTPH-2A Phono Preamp | Steve Hoffman Music Forums

I've not seen an amplifier that does not respond to rolling and this post sums up what to expect.