I guess by "phono amp with volume" you mean a preamp with a phono stage built in. And by "two pre-amps" you mean a separate phono stage and line stage (with volume control, switching functions).
I prefer a complete preamp (with a phono stage) to two boxes. That's how all preamps were built 20 years ago.
A separate phono stage is more complex than when this functionality is built into the preamp, due to requiring its own power supply (obviously) and needing extra circuitry to drive the interconnect cable between the two units - compared to when this connection is accomplished with a very short length of fine silver wire in a complete preamp.
And of course, you need an interconnect cable.
But some audiophiles love 2 distinct units.
Regards,
I prefer a complete preamp (with a phono stage) to two boxes. That's how all preamps were built 20 years ago.
A separate phono stage is more complex than when this functionality is built into the preamp, due to requiring its own power supply (obviously) and needing extra circuitry to drive the interconnect cable between the two units - compared to when this connection is accomplished with a very short length of fine silver wire in a complete preamp.
And of course, you need an interconnect cable.
But some audiophiles love 2 distinct units.
Regards,