Hi guys i have just purchased a new old stock ignition amp for my Pre he, the amp i purchased is an AB 3 the same as the original from the car but it has the extension leads so it can be mounted out of the V. Now the new one does not have a seperate cable from the amp to the ground on the coil, instead it is joined at the balast resistor on the white / black wire. Should i be concerned? or was the stock white / blue wire to the coil uneccasry if you take the ground straight from the resistor?

Thanks