I play Carvins. Up until just a few years ago, Carvin pickups & preamps were mediocre, at best. Since I began buying Carvins during that period, I've pretty much stayed in the habit of having them upgraded with high-quality aftermarket electronics, i.e. DiMarzio, Nordstrand, Delano and SGD pickups; Aguilar, Bartolini and Audere preamps.
From what I gather, Carvin electronic components have improved significantly during the past several years. While they're not at boutique levels of quality, they're decent and playable.
If/when I buy any more Carvin basses, I reckon I'll still have the electronics upgraded. One possible future build is a new LB75 with custom Kent Armstrong soapbar humbuckers, and/or a new LB70 with a set of Seymour Duncan Pro Actives. As for preamps, I like the Aguilar OBP-3 for rock, and anything by Audere for all other, more hi-fi applications.
MM