Control theory provides solid foundations for developing reliable and scalable feedback control for software systems. Although, feedback controllers have been acknowledged to efficiently solve common classes of problems, their adoption by state-of-the-art approaches for designing self-adaptation in legacy software systems remains limited and at best consists in ad hoc integrations, which are usually engineered manually. In this paper, we revisit the Znn.com case study and we present an alternative implementation based on classical feedback controllers. We show how these controllers can be easily integrated into software systems through control theory centric architecture models and domain-specific modeling support. We also provide an assessment of the resulting properties, quality attributes and limitations.