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

I think my thinking is in line with MC's here.  There is no piece of audio gear that could not be picked apart by a hobbyist competent to read a schematic and understand the circuit.  Even those FETs could be substituted by a knowledgable engineer who can solder.  The diodes might be upgraded if they are not already Schottky types.  You could "upgrade" the resistors using nude Vishays, at $12 a pop.  Capacitors are always a target of the cognoscenti.  And yadayada. I've been down all of those roads myself, but I finally concluded that sometimes it's better to leave well enough alone.

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.

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.

Please describe what listening to an FET in the context of a tube circuit sounds like. ARC preamplifiers are certainly not known for warmth. FET/tube phono stages can be among the most neutral. I certainly don’t mention it as a criticism of the Herron. My Manley Steelhead is also a hybrid as are many other phono stages we like to think of as “tube” types. Typically you have at the input a cascode consisting of a FET on the bottom and a tube on top. That gives tremendous gain and very wide bandwidth. It also eliminates or drastically reduces input capacitance. My point was that in this topology much of the gain comes from the FET. Therefore shuffling tubes downstream would have less noticeable effect on SQ, compared to an all tube circuit. Alternatively the FET drives the grid of what would be the first gain tube in a conventional tube RIAA. The FET acts like an outboard head amp .

Also because if you’re using an LOMC cartridge, you’re basically listening to an FET. If I understand the Herron phono correctly.

I suspect the Herron might respond less obviously to tube rolling because it uses an FET (transistor) in its MC gain stage. Thankfully, transistors are hard soldered in place. Otherwise folks would be transistor rolling. Is there some reason to believe the Rogers unit would be competitive with the highly regarded Herron? Why would you use tube rolling as a criterion by which to judge? Real improvements to be obtained by tube rolling, unless the replaced tube is worn out or defective, are very limited and subjective only. Usually the practice does not raise one piece above another if it was inferior to begin with. In my opinion.