If you are talking about a phono preamp for genuinely low LOMCs, it is not really possible to get the high gain/low noise needed with just tubes. Hence the need to use opamps, FETs, SUTs, etc., to do so. Even the ARC Reference Phono 10 uses
FETs in addition to tubes.
Of all the options available to get the high gain/low noise needed for LOMCs, many prefer using an SUT because it is a passive device (no active circuitry or power needed). If the SUT is properly designed and mates well with your cart, they can not only be no/low noise, but also provide more dynamics, liveliness, and texture. YMMV.
Of all the options available to get the high gain/low noise needed for LOMCs, many prefer using an SUT because it is a passive device (no active circuitry or power needed). If the SUT is properly designed and mates well with your cart, they can not only be no/low noise, but also provide more dynamics, liveliness, and texture. YMMV.