Basically your Hellraiser has EMGs in it. When changing to BKPs or basically any of the usual pickups, you have to change your pots too.
I found this, and thought it could be a nice answer:
"The EMG pots are 25k pots. They're an active, low impedance system. While you can use the EMG's with higher value pots, it's not desirable - because the pot becomes more of an on/off switch than a pot: At 0 you have no signal, then at 1 you get 50% output - which means you won't be doing any smooth volume fades with those pots.
Traditionally, 500k pots were used for guitars with humbucking pickups (i.e. Gibson), while 250k were used for singlecoils (Fender). I believe most major manufacturers stick to this principle."