Hi . I have bass (ZON Sonus 5) with custom installed: Bridge: Bartolini XXM55C-T 5 String Soapbar Neck: Single bartolini pickup (Standart) 5.4 Bartolini electronics with 3 EQ, Active/Passive, bend, mid switch. And i have problem with it: When bend is fully on neck pickup - Perfect sound. When bend is fully on bridge pickup - Perfect sound. When bend on both pickups i have low volume level on 2nd and 4th strings. I think that problem is in different pickups. And i want to install: Neck: Bartolini XXM55C-B 5 String Soapbar Should i replace Bartolini preamp or standart preamp used in 5.4 kit will sufficient? Sorry for my English.