RXJS Emit first result and then wait for another observable

Currently I have two observables. One returns a list of clients and the other is fired when text changes.

I would like to emit the full result of clients and then switch over to the inner observable once the user has started filtering.

I'm also trying to achieve a debounce on the text being typed.

I've put together something that doesn't work to try and explain. As it currently is it only displays clients once I start typing text.

let obs = Observable.fromPromise(this.clientService.getClients())
      .map((clients) => {
        return clients.map((c) => new Client().fromObject(c));
      });

    this.clients = obs.switchMap((values) => {
        return this.searchText.valueChanges
          .debounceTime(400)
          .distinctUntilChanged()
          .map((text) => {
            return values.filter((c) => c.isMatch(text));
          });
      });