Phono preamp's all have hiss no matter what price or type. Most modern amps have very high signal to noise ratios on line level inputs . Turning volume up to max ( an unrealistic level usually !) will still sound noise free ....that's not no noise in the system but so low that you can't hear it easily ..be it hum or hiss. Phono stages have hiss because the input stage generates hiss when connected to a large impedance ( phono cartridge load ) and it does so due to laws of physics . No one can wish it away but could minimise it close to the theoretical level possible with that load. Hum on the other hand could be from the power supply of the phono stage. Something you cannot deal with easily , or from hum pick up from the cartridge platter combination ( like Grado cartridges and platters made of magnetic material ), or just poor grounding of the turntable , cartridge, socket assembly. Poor RCA plugs too.
Switch off power to the turntable and place the stylus on a stationary record . If you get audible hum then it is most likely your grounding scheme to the turntable or the phono preamp itself. If all's well then lift up the stylus a bit, say 5mm from the record surface and turn on the turntable. If the hum levels appears or increases it could be hum pick up from the cartridge/platter combination . Double check the grounding again !
Hiss on the other hand which is varying would be due to poor connections ( oxidised usually !) or basically the noise ( constant noise ) produced by the phono and preamp combination. Typically a good phono stage with cartridge connected has audible hiss if you crank up the volume . This is normal. There is no such thing as no noise in any system especially a phono stage. It is is all relative to the maximum signal in your system. So a 90dB signal to noise has hum and hiss at a level 90dB below the maximum signal level say 5mV coming off your cartridge or about 1 Volt from your preamp or full undistorted output of your power amp. This is pretty noiseless at max volume.
Phono stage noise in a good system is usually around +70dB which is pretty good. But you will find they vary a lot between preamps and cost is no indication of it. A $38,000 Boulder (!) phono preamp had a measured S/N ratio of about 58dB weighted ! That isn't impressive at all. While a LKV Research phono preamp had a 90dB S/N ratio weighted ! That's very impressive . But they don't say how the measurement was made. With a load or connected or with shorted inputs.
However the moment you put the stylus on the groove all that doesn't matter so much as the best S/N ratio you can get from the groove stylus combination would typically be worse than 60 dB . Stylus shape contributes a lot to this. Better shapes costing significantly more. Typically vinyl which give a 60dB S/N ratio( usually just 55dB !) is MUCH noisier than the phono stage . The phono stage noise gets added to this and if it is 6 or 10 dB better than what you can get from a playing vinyl disc then it's fine . No need for 80dB S/N from a phono stage etc. But high end designs could routinely produce better than the 80dB figure. Do you need it ? Not really when you are playing music off a disc. It gets audible during the silent parts of the music and so is also music type dependent . For Metal music it wouldn't matter at all but become significant for soft classical music . Or even music by the modern generation like Koji Kitaro etc .
So focus on what you are getting at your listening position and volume setting and forget about what happens at maximum volume which is unrealistic and also affected by gain of the different stages and loudspeaker sensitivity etc. Much of which you cannot change easily. Just ensure that the connections are all OK and it's got hum down to a possible minimum in your system. Then sit back and enjoy your music along with the vinyl/phono stage hiss which will always be there. Trust that it is minimal in your system at "listening levels". Buy modern pressings or premium brands ( Mobile Fidelity etc ). Modern records apparently use better plastic , at least they say so ! Old generation vinyl have variable noise levels and depended on who pressed it . Some plants used better plastic material, typically Japanese pressings, and usually cost more too. Enjoy !
