how do i connect two amps to my one sub
 

i have a sony 250 w amp running a pioneer 700w sub and i want to know if or how i can add another 150 w amp

no

i guess u want to connect them in bridge mode ,
if so u need 2 identical amps

Assuming they are either single channel amps (which are usually internally bridged anyway, so prolly not) or a dual voice coil sub.

If your Subwoofer is not a dual coil type, then i would not attempt this.
Just be happy with what you have, more power always means more heat, The Pioneer subwoofers have nice voice coil formers but they can only take a certian amount of heat before failure.

one other thing is, your Pioneer has a Maximium power rating of 800 watts, this is a dynamic rating and not a RMS rating, if you attempt to apply this much power too your subwoofer you will reduce its life span, am talking days even hours, oppsssseee!

I couldn't have said it better .. . :D

thanx for your help
 

thanx for your help

which are usually internally bridged anyway


Not exactly !! A mono amp is just that. It's not internally bridged.

Not always. Take a look at the of the lower prices, high power amps.. most of them are internaly bridged.