What is this sound and what exactly causes it to happen?

[jerjabs]

There is a certain sound some Marshall / clones create. I "think" I've heard it described as a "chirp" or glassy tinkle / crunch. Some amps do it a lot... some you seem to have to coax it out of or don't do it at all. Here are some examples of what I'm talking about. They are very quick chirps.

In this clip you can hear the chirp at EXACTLY 0:36 and 0:50
https://www.youtube.com/watch?v=pmPxSaP9NDw

In this clip you can hear it more often during the SLP demo at 0:24 - 0:28 - 0:31 and 0:32.
https://www.youtube.com/watch?v=Z9gAXfqN0h8

What causes this to happen and what can I do to make sure the amp I buy will do it? Does the amp need to be cranked to achieve this beautiful effect?

THANKS FOR YOUR TIME AND HELP!!!!!!!

[Tazin]

Not sure if we are both hearing the same thing but to me it sounds like the resultant of pick attack when the amps volume is way up. Some of the sounds around the time indexes/indices you listed sound like up-stroke picking.

[jerjabs]

It is when the pick it hitting the string(s), but there is a high pitched chirp or clink it makes and not all plexis seem to produce that amazing tone.

[Scumback Speakers]

I would go with pick attack as well, not to mention the gain and volume accentuate that type of picking. You probably can't make that sound with a clean amp at low volume. IMO, nothing to worry about!