I bought a equilizer to fix it to my 307.
To get power for the equilizer shall i connect the B+ & ground on the equilizer to car stereo B+ & ground? EQ has its own on\off button.
Or should I need to get the power directly from battery.
you'll need to find out what power requirements it needs and if the radio gives that requirement. what i did when i fitted an amp is got the B+ going to battery, ground going to a bolt attached to the metal bodywork in the boot, then there was a remote terminal which i connected to the radio along with the signal cables (running power and signal down different side of the car) so that the amp will only be on when the radio is on.