The Leben RS-30EQ is equipped with the CR-type equaliser based on the GE (General Electric / USA) 12AT7, authorised by the J.A.N. (Joint Army and Navy) standard of the US Army and can reproduce a very high quality and clear sound without adding any NFB (negative feedback). To avoid compromising sound quality using the NFB circuit type, one of the solutions Leben adapted to protect the sensitive CR-type equaliser was to develop a high quality 'Orient-Core' power transformer perfectly shielded to shut-down hum noise from the transformer. Leben have also selected the finest available high-end audio components to keep the deflection of the RIAA curve below +/- 0.2%.