What do you think causes the crackle and clicks we hear?

would disagree on static discharges, and some of the other ideas.

Have looked into this for a long time and taken many microphotographs of LP / vinyl groove surfaces.

first you need to understand what is  mixed in with vinyl pellets before the record pressing plants ever sees them. Many think mold releases are used. Have not found that to be the case.

But during PVC pellet processing, Calcium carbonate is added to almost all vinyl formulas during formulation as a processing aid for all the manufacturing steps, from extrusion, to pelletizing to molding.

during the record pressing cycle, the calcium carbonate is still in suspension in the PVC vinyl matrix during the heating cycle. During the cooling cycle, the rapid change in temperature causes the Calcium carbonate to migrate to the the cooler surface, collecting in the bottom of every groove.

As the stylus tracks the groove, the bottom of the stylus is hitting the tops of these larger particles. Want evidence? Take a look at the bottom side of your cartridge. you will likely see some fine dark white to light tan tiny particles clinging everywhere. these are tiny calcium carbonate particles the stylus removed from the bottom of the groove.

Have looked at over 300  records under a microscope and have never found one without the deposits.

Removing the calcium carbonate is the key to removing ticks and pops, and general groove noise. and its tough to do. But one done, its amazing how much better your vinyl will sound.

it can be removed with an ultrasonic machine as well as a vacuum type machine (VPI or nitty gritty).

Both require numerous passes on each side to remove the particles.

But once removed, your records will get amazingly quiet and the resolution and imaging will improve much more than swapping in a new phono cart.

best









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@mijostyn

If I could post photos I would, I have over 300 JPG files of groove images and all show carbonate in the bottom of the groove. so not sure what grooves you have looked at.
All I am doing is trying to remove some of the mystery behind LP cleaning and show more that getting clean LPs requires a bit of work if you are using VAC or US type cleaners, and can be done.
Have not tried the sink wash type cleaners so can't offer any insight on them.

If anyone wants to do a simple test, its quite easy. can be done on a vac machine (VPI or NG). use your favorite cleaning solution, apply it to LP. spread evenly across the LP surface.  Let is sit for 10-15 min then vacuum off.
Go play the LP. you will notice a much quieter background.


  

@ mijostyn, no worries. I used to think exactly the same; keep records from getting dirty in first place; be super anal about not letting anyone else handle them, etc. That was key to clean records.

But now realize that is not the case. The particles in the bottom of the groove are from the cooling cycle of the pressing process or operation during LP manufacturing, so are completely independent and totally unrelated to how clean or how well you handle or dont handle your records, brand new or old. 
I will say the 180 gram and 200 gram LPs I have looked at do have a lower level of particles in the groove than the 1970s and 80s LPs, so there is more care taken with these than the earlier commonly released titles pressed by whom ever. But these particles are still there. 

I have a large (but not huge)  collection, with many LPs from the 1650s-70s, plus many re-issues from Speakers Corner and Acoustic Sounds. For years I always thought the VPI or NG were made for removing finger prints, dust, lint, etc.

Once I realized that was not the case, then the door got blown off on my original theories on LP cleaning that have been drummed into my head by so many over the years. So then had to experiment to see what worked to remove  the white particles. Many trials of cleaning, then looking under the scope to see if I mad a difference or not.

If anyone knows how to  post photos to this blog would be happy to do it, but in the past have tried that with no success.

if you use a stylus cleaning solution, take a look in the solution. It should be loaded with white particles all floating around in bottle.

And once you get the grooves free of 90% of the particles, you will be amazed at how much lower the noise floor becomes, and how much more ambience is pulled from those grooves.

@tuberollin has a point. I have heard the impovement as well.but regardless, still need to get the carbonate particles out of the  groove so the stylus can actually track the groove to much more information that is hiding in those grooves.