The amal valve has 3 pipes and is electrically connected to the ECU:

-from the turbo
-to the actuator
-to the air filter housing

When the turbo starts to produce boost, the pressure coming from the turbo will be diverted into the airbox, because the amal valve is powered by ECU.
This means boost will rise quickly, because no air is going to the waste gate actuator.

At a certain boost level (programmed in ECU) power is taken away and all pressure from the turbo is sent to the actuator, which will then take over completely.

So the amal valve is a way of getting the boost started as quickly as possible.

If you disconnect it, all boost will be diverted to the actuator, therefore boost will build slower, because the spring will give way already in early stages of boost build up.

This is the story for a standard car !!

Cheers