First of all, a bit of backstory. I am not an audiophile, I sold all my records last year and I stopped buying in 2008 - but there's DEFINITELY a difference in sound.
Want to know what it is? It's literally a separate master. There's limitations in one format, so us engineers have to work around 'em and guess what? A lot of us like "warmer" sounding records... So we colorize them.
...But you know what? It's not analogue - it's purely digital. Right now, the most popular tool is the new version Crane Song Phoenix, pictured here:
Me and my friends also only do stem-mastering for vinyl these days. We get 3-6 tracks so we can colorize them differently. It's a very quick process and makes a big difference. Very cheap for the client as well.
It's literally a different master - so it will sound different. Most clients want it to sound warmer. I know a bunch of people who got tons of jobs in the late 90's because they simply cranked the master to tape before they pressed it. It's not a new thing and it's all about knowing what people expect from the format.
...Spazz is my 3rd favorite band of all-time though. Why is this guy not guest-blogging for that stuffyouhate site instead?