Strange that you didn't hear this with the prior amps.
I had exactly the same furnace ignition 'click' with my dedicated circuits. It is the grounds which are contaminated, they feed household garbage through the ground.
The only cure that I know of is dedicated ground for the dedicated circuit. Be aware this can be dangerous in lightning storms as ground potential differs between whole house ground and dedicated ground. Maybe lifting ground on amps will solve as well.
I had exactly the same furnace ignition 'click' with my dedicated circuits. It is the grounds which are contaminated, they feed household garbage through the ground.
The only cure that I know of is dedicated ground for the dedicated circuit. Be aware this can be dangerous in lightning storms as ground potential differs between whole house ground and dedicated ground. Maybe lifting ground on amps will solve as well.