Every record collector or anyone in pursuit of the best pressings should watch this in it's entirety. A Hot Stamper refers to the level of the volume the presser used the day he cut the master lathe. An amplified volume would in most cases sound better,an under amplified volume makes for a dull flat pressing where as there is a standard industry norm which is used mostly. Micheal Fremer weighs in on this on this link,he also weighs in on why you should avoid Record Club Pressings (Columbia,RCA and BMG)
https://www.youtube.com/watch?v=eKcV430APoo
https://www.youtube.com/watch?v=eKcV430APoo