I can't help with the preamp (although it all sounds in order - a rebranded Seymour Duncan pre), but I will repeat myself with regard to your amp.
You said the bass sounded fine through the seller's amp, but you got it home and through your amp you were hearing distortion and the B-string wasn't 'satisfying'. The poor tone was what originally made you believe something was wrong with the preamp, yes?
You also said you had a 15 watt amp, and that it helped when you didn't have the bass's onboard EQ completely maxed out. Regardless if whether the preamp is the stock one, and provided you have a fresh battery in the preamp, my advice is to play it through another (much bigger) amplifier rule out your 15 watt amp at home.
I shouldn't need to spell out why a 15 watt amp could be the issue.
You said the bass sounded fine through the seller's amp, but you got it home and through your amp you were hearing distortion and the B-string wasn't 'satisfying'. The poor tone was what originally made you believe something was wrong with the preamp, yes?
You also said you had a 15 watt amp, and that it helped when you didn't have the bass's onboard EQ completely maxed out. Regardless if whether the preamp is the stock one, and provided you have a fresh battery in the preamp, my advice is to play it through another (much bigger) amplifier rule out your 15 watt amp at home.
I shouldn't need to spell out why a 15 watt amp could be the issue.
