Issue with Phono Playback.

By 'snow', I take it you mean you hear a slight hissing or white-noise sound. This is the noise level of the headphone amplifier in the Sony receiver. A better quality headphone amplifier would have less or none of this noise. But it is not terribly offensive if you don't notice it while music is playing. Since it doesn't distort the music signal you can "listen through it". Of course a small amount of low-level detail is being obscured by this noise. When you have complete silence between notes, rather than some amount of noise, it brings the music into sharper focus and in my opinion makes it more dynamic and lifelike.

The high note sound may be distortion - I thought a "plosive" was the sound made when air is forcibly expelled from the mouth, like saying the letter 'P'. This is a normal sound if it doesn't overload the microphone. Your sound that only occurs on high notes may be a distortion of the signal and could be caused my a number of things, maybe related to the phono cartridge alignment or stylus wear, or maybe an electronic problem in the receiver, like an aging capacitor or transistor. You could try a CD of the same recording and see if it distorts in the same place. If not it is probably something with the turntable setup rather than the receiver although it could still be in the receiver phono section.

That's about all I can think of, hope it is helpful.