I just installed an aguilar obp-3 preamp using an 18v setup. However my pickups bartolini to be exact used to use a 9v input throught the red wire. I have used this exact setup and it works but does anyone know the effect of applying 18v to my pickups? Would it fry them? I dont know the exact model of the pickup but its on a Conklin gt-7 bass.
Please let me know.

You are safe, you can run 18v in series no problem. Barts don't care about the amount of power, well unless it is a crazy amount.
Dirk

Well i am a bit concerned that i might have fried the pickup by feeding it with 18v .. I will give it a try and get back to you let you know how it worked out..

Works like a charm thank you.!!!