Observable emitting “custom” object

I am trying to emit a custom object from my observable:

export class DataService {
  private currentUserSource = new BehaviorSubject(new Employee());
  currentUser = this.currentUserSource.asObservable();
  constructor() { }

  changeValue(user: Employee) {
    this.currentUser.next(user)
  }
}

If I understand correctly, then the next() method is used to emit a value to the observable stream. It works with strings and so and without an issue, but when I want to emit an object of type Employee then it fails with:

[ts] Property 'next' does not exist on type 'Observable<Employee>'. [2339]

So, how can I emit the object, when it's a custom class.

Here is the class, just for completion:

export class Employee {
    login: String;
    name: String;
    firstName: String
    active: boolean;
    phone: String;
    hourly: number;
    SessionKey: String;
}