When playing a mono vinyl record with a stereo phono cartridge the separation of the noise and music is quite noticeable (especially with a particularly noisy record) because the music seems to be centered in the middle between the stereo speakers/headphones and the noise seems to appear in the speakers/earpieces on each side which makes the noise much easier to ignore. But if one uses a mono phono cartridge or sets the playback to mono, then the noise also appears in the center between the speakers/headphone earpieces and mixed with the music rather than being separated from the music which then tends to obscure the music. Therefore, I recommend using a good stereo cartridge to play mono records over a stereo playback system.
Wow. Holy crap. A revelation to me, like a light bulb switching on. In one swell foop (yes, I wrote that on purpose) George has shined a light on a puzzle that has plagued me for decades. Why is surface noise, ticks and pops in vinyl separated from the music itself? The answer had never occurred to me - yet now it seems so obvious.
There are two completely separate activities in play when spinning vinyl: the needle plowing through pre-recorded grooves containing musical information and that same needle tracing the surface noise and defects in the vinyl medium. Voila!
Not clear yet? Imagine a phonograph record with no musical content, identical to what you find between tracks. What do you hear? Surface noise, ticks and pops - and when you use a stereo cartridge - the random noises present a wide stereo soundstage (if you will) of the noise - like a three dimensional bed that anchors ones senses, defining the space we're going to listen in. Once music begins we have added yet another element that is separate from the surface noise- and it sounds that way.
Add to that my conviction that much of what helps vinyl sound live/convincing is this bed/foundation of three dimensionality that helps our brains define space boundaries. You can hear this same effect in a live audience. The next time you're attending a concert, close your eyes before the musicians begin and you can sense the size of the hall and its acoustic boundaries by the background noises of the audience. Those noises anchor your senses and help the live feel - apparently, this is in large part why vinyl is so well liked too.
And here's the thing. If you make a digital copy of a needle drop, guess what? Those two separate events are captured perfectly - and they remain separate because THEY ARE separate.
Thanks George, you've helped my understanding and made my Saturday.