Enginedr1960:
Well written, I have found that on some systems 60dB seems like it should work but that in fact 66dB is required. Why? Not sure, perhaps the stated gain of the phono is off, perhaps the cartridge is not as strong as the spec sheet states. Gain structure throughout ones system does play a huge roll in the results one receives.
Obviously if I set my phono gain to say 40dB (I'm being extreme to illustrate a point) with a 0.3mv cartridge, no amount of gain in the preamp is going to negate the anemic signal from the phonostage, garbage in, garbage out.
Either way, as you stated it is system dependent and your ears are the most important measuring tool, so to speak. I currently run a active / passive pre (Wyred4 Sound STP SE) and I never have to go into the active gain range of the circuit, yet the dynamics can startle, if the music is dynamic. I have a professional recording engineer coming over this afternoon to bring some safety master tapes because he likes my system and wanted to use it to hear some of his work.