I can recommend the NJ4SVs unreservedly. Joelb79's characterization of them as "wonderful pickups, but a little hi-fi sounding" is about right, I guess. His Warmoth J was set up via materials/etc. to be a bit brighter out of the gate than mine. The extra sparkle compared to the EMG-JVs I had on there before was just the ticket for me.
Could you describe what it is that you want tone-wise, from the pickups?
I would say mainly that you should evaluate what it is you want out of an electronics upgrade.
With the EQ flat, is the tone from the pickups what you want? You mentioned some dissatisfaction with the Fender preamp.
- If you're happy with the tone from the pickups themselves, and just want better tone shaping, then I'd say upgrade just the preamp.
- However, if it's the tone of the pickups themselves that you're wanting to be better, then a pickup upgrade it is!
- If you're fed up with the whole mess, then evaluate whether the best thing is to upgrade all of the electronics, or get a whole new bass.
Either way, I'd suggest do one of these operations at a time. It'll save you money if you happen to find your tone Nirvana after swapping out only the pickups or only the preamp. Contrary to my own advice, I did both at once though... but I had no choice: the EMG-JVs I had were active and thus wouldn't have worked through the Audere preamp I was getting.
Either way, be sure that this bass is a keeper. Spending $ on electronics upgrades won't result in a 1:1 rise in the sale price of the instrument should you eventually decide to let it go. I had my Warmoth for 8 years, knew it by heart forwards, backwards and upside-down and was fully convinced that I'd never want another fretted 4 before I pulled the trigger on the Nords + Audere + new bridge + other small upgrades. Took a fair chunk of $, but it brought the instrument up to the perfection for me.
Here's hoping that your upgrade experience can be as fulfilling as mine.
