Btw, atmasphere I don’t care about class D amps. I was very specific about: design of SS phonolinepreamps.
Of course you don't - that would not help your argument. The bigger point here is the need to be right for the sake of it, rather than being factual. While you may 'not care about class D amps' the simple fact that we can make one that is of our own design, and that we can get a patent in the field, is enough for anyone to know that if we wanted to make a solid state phono section, we could and with ease.
*****************Back on track:
One advantage tubes have over solid state in phono preamps in particular is that of overload due to the electrical resonance caused by the cartridge and tonearm cable (inductance and capacitance in parallel; please ask me if you don't know what I'm talking about here). In solid state circuits, if this resonance goes into excitation (oscillation) the resulting RFI can overload the input circuit. This can result in a tick or a pop, and is part of the reason that many people think that ticks and pops are endemic to LPs.
But when a producer makes a recording on LP, he gets what is called a 'test pressing' which he listens to to see if its alright. A form accompanies the test pressing, and the producer has to sign off on it, approving the test, saying that the stamper is good and the LP production can proceed. One of the things producers listen for is ticks and pops in the LP. So when they sign off, its on something that shouldn't have any ticks or pops.
If your phono section is immune to the RFI generated by a LOMC cartridge and the tonearm cable, its common to hear entire LP sides with no ticks or pops at all (unless the LP clearly has a scratch). (For this reason, I frequently get asked at shows if I'm playing a CD- I just point to the turntable.)
This immunity comes from four things- preventing the RFI from getting in, making sure that each stage can't oscillate (with tubes or discrete devices, a 'stopping resistor' is used for this purpose), the circuit has enough high frequency overload margin that the RFI can't overload it (keeping in mind that the RFI is a peak of 20-30dB) and finally that the circuit does not rectify the RF energy.
With tube circuits, if a tube is at the input directly (as opposed to an SUT) the RFI won't be likely to overload it. It might send it into oscillation if a stopping resistor isn't present, but if its there, then overload won't occur.
(A fundamental difference between solid state and tube phono sections is where the overload occurs if a strong signal is applied to the input of the phono. With solid state, the overload can occur right at the input. With tubes, its likely one or two stages downstream.)
Normally a 'cartridge loading resistor' is used to detune the RF resonance of the LOMC cartridge and tonearm cable. Eliminating RFI from audio circuits can affect how they sound; this is part of why you hear differences with loading vs no loading (although it can affect tracking too). But if you have a tube preamp, its far more common that loading simply won't be needed (SUTs excepted- that's a different set of conditions). Its much harder to get a solid state phono section to behave in this regard since semiconductors have diode junctions in them, and these junctions can rectify RF energy. For this reason, solid state phono sections that don't need cartridge loading are less common than they are with tube phono sections. If the RFI is rectified, this sits in the noise floor- and because of its structure, prevents the ear from penetrating the noise floor to extract more detail (natural hiss is one of the very few exceptions to the ear's masking rule).
If your preamp has loading options built-in for LOMC cartridges, its a good bet that the designer didn't deal with the RF resonance. If he had, the performance would be better.
So while tubes might be a bit noisier than solid state overall, you can more easily have less ticks and pops which to me is preferable. And as long as the phono noise is less than that of the cartridge tracking a silent groove on the LP, you won't hear it. That's very doable with cartridges of 0.2mV, which is about as low as cartridge outputs go with very few exceptions.
