Have you tried another amal valve? Is yours working?

If you've got the compressor directly connected to the actuator you'll get whatever amount of boost you've set by the preload on the actuator's rod. If you have the amal valve connected, the ECU will be able to control the boost as best it can. Don't forget that the ECU will (or should!) wind the boost down if the inlet temp appears too high.

Do you have another actuator to try?

Check your boost hoses for splits.