bartolini preamp on a new g&l 1505 bass

Ibought a new 5 string g&l 1505 bass, my first 5 string.After playng it for 2 hours or so,i noticed that when i activated the preamp,(active mode) there wasnt a big difference in the sound.Also there was no shielding in the back cavity,and it hissed a bit.So i bought a bartolini preamp harness from planet bass for $125.00,and had Barry Lipman from the eastcoast music mall in Dambury Ct. instal it,and put in a copper shield that i bought from carvin.Now, the bass is a lot better,no hisses,it sounds like a million dollars.Im only sad for one thing.Iguess that barry or one of his helpers tightened the nuts under the knobs too much,and the finish cracked from the first knob to the last,right on center.Too bad,but things happen.He said the crack was there before,but i know it was not.