software

I want a new bridge pickup, and right now I have a Jackson J50BC that has an output of about 8.6k. I was thinking about getting a parrallel axis Distortion trembucker but jumping from 9 to 21 k of output may be a shock... What am I to expect?
Would I lose a lot of soun quality if I opted for a Custom for instance?

You're not giving us nearly enough info to go on. What kind of music do you play? Do you like the overall tone quality of the stock 8.6k pickup and just want more output and punch, or are you also looking for more bass, mid, or treble?

I'm not sure what you mean when you ask about losing sound quality if you go for a Custom. Compared to the stock 8.6k or the 21.3k Distortion Trembucker?

A 21k pickup is going to have a lot more output and probably a lot more midrange than a 9k pickup.

Without any answers to the above questions, I would say try something like a Custom (14.1k) out first because it's probably all you need and you might lose some top-end clarity going to a 21k pickup.

The high end will be attenuated, and the pup tone will be harder (not heavier, think bludgeoning).

I went from listening to my A2P in the bridge slot of my Heritage to a Custom/Distortion hybrid, the real shock was the harder clean sound, and the aggressive edge.

Luke

You can make up some for the loss of high end (if it's a problem, that is -- you may actually like tone with the slight loss of treble) with a higher value pot, which will prevent the capacitor on the tone pot from draining away as much treble -- which it does a little bit even with the volume at 10. With a 21k pickup, I would seriously consider a 750k or even a 1 meg pot.

In my opinion, you'll be happy if you swap that pickup with either a

Custom
Custom 5
Custom Custom
JB