What exactly causes clicks and pops on vinyl?

Amazing with all the above descriptions the simplest one was skipped... Static
Static control is one of the biggest factors, no doubt I agree that the particles on the surface or welded into place from debree is just as much an issue, normally once cleaned and stored correctly 95% of this disappears in my experience.

If you have a lot of LOUD pops its most likely static, little surface noise and clicks is normally Debree which is only sticking to the surface due to Static holding it there in the first place.

So I guess containing your turntable cartridge in a low static environment, treating the vinyl storage with care, humidity, and possible little tricks like the Milty Zerostat guns etc... Sometimes will come into play for some peoples situations.

"When about to play LP, swipe it with an Audioquest Carbon fibre brush to remove static and stray debris." I'd almost say create static instead of remove it. How do you make a balloon stick to the wall? Those brushes create less static but not zero static. Seriously, try playing the record first then rub it to find out what it is doing. If you've never played a record without using the carbon brush, you really should try it. I'm sure I'll get a response about using it properly as to be grounded, etc. but it is very much like using a broom without a dust pan. Also, by the edge we mean not touching the surface at all, not picking up the LP with your finger and thumb. I think an earlier poster did not grasp the concept of the "edge".

Acoustat6...I am not a Trekie, so I never heard the Scotty/Spock statment. But it's so true.

This axiom was promulgated back in the 50's by a Japanese engineer, Tagushi, who was a disciple of the great American QC expert Dr Edward Deming. Post war Japanese industry, notibly Toyota and Sony, had adopted the philosophy, and look what it did for them. In practice I learned this lesson in my work on missile guidance systems. Back in the 60's our electronics had lots of precision components, many selected-value components, and even a few pots. Over the years, as performance requirements on the GS tightened up it became evident that, cost asside, it was simply impossible to meet them by using more and more precise (exotic) components in the circuitry. Today it is a requirement on the design of the GS that it not rely on components of unusual precision, and have no selected components or pot adjustments. This puts an additional burden on the designer, but in the end it results in a system having superior performance, and reliability.

Something else that helps is to avoid phono sections that employ any sort of loop feedback. A zero feedback (passivly equalized) phono preamp will tend to make less of the ticks and pops fed into it. I have seen it be the difference between 'annoying' and 'nearly silent' (in extreme cases). BTW most zero-feedback phono reproducers will be vacuum-tube.

Atmasphere,

There is another thread on Audiogon that talks about record cleaning rituals that includes a lot of different ideas about how to get a record clean.

The most deadly kind of click or pop is due to a scratch on the record, meaning the physical surface of the record has been gouged or damaged, most often by some wayward or accidental bumping or moving of the stylus ( the tip of which is much harder than the material that the record is made of and hence scratches it upon contact). Of course there are many other ways to scratch a record as well. A scratch of this nature will often be evident upon close inspection as a sharply formed linear feature on the surface at some angle to the direction of the grooves. Stay away from used records that evidence scratches of this nature because there is not much you can do to fix it once damaged.

Defects in the cutting of a record (defective grooves) often manifest themselves in the form of other types of undesirable noise or distortion. These are generally harder to detect upon inspection, but with some practice and trial and error, it is possible to spot many vinyl albums with groove damage in advance.

Foreign material on the surface of the record also produces noise of course, and can also accumulate in denser clumps that manifest themselves sonically as a pop or click, though not a visible scratch. A good cleaning can usually put an end to this kind of problem.

Hope this helps.