From 2000-2008, my bass had a set of EMG-JVs on it.
In the summer of 2008, I swapped them out for a set of Nordstrand NJ4-SVs (the split coil humbuckers that are wound to sound as close to the NJ4s as possible)
The change was precipitated by my choice of an Audere as the new preamp on my bass. The EMG-JVs, being active, wouldn't jibe with the Audere Z-mode preamp, so I did an entire electronics swapout.
So, I've got 8 solid years of my ears knowing the sound of the EMG-JVs and a good year of hearing the Nordies in the same bass.
I've never had what you might call a set of "classic Jazz bass" pickups in my bass, and my bass is a Warmoth with an all wenge neck and a korina body, so the classic Jazz sound isn't quite in the cards. What I can say is the differences between the EMG-JV and the NJ4-SV as
I perceive them. All information below is purely subjective, from my ears only.
All told, the tonal differences aren't extreme. On my first moment plugging the bass in and hearing it with different pickups, I didn't go "Oh, what happened? This isn't the same instrument!" I'd had 8 years to absorb the tone of this bass, and being my only instrument (other than a Steinberger that I experiment with tenor/alt-tunings on) I know the tone of this instrument inside out. So in that respect, if the EMG-JVs and the NJ4-SVs are aiming for the same tonal ballpark, it seems they've reached a level of similarity as far as my ears can tell.
The differences I've heard:
- The EMG-JVs were darker sounding than the NJ4-SVs. The Nordstrand pickups give more of the high-end treble part of the sound.
- It's hard to describe exactly, but the Nordstrands have a nicer sounding midrange character. I can't call it thinner exactly.. in the pejorative gets-buried-under-a-guitar way. It's not that. The NJ4-SVs have a better character to the sound in that vocal-midrange area.
All in all, I prefer the trade.