In this work, new circuit configurations for realizing biquadratic all-pass and notch filters - canonical in the number of active and passive elements - are presented. The proposed circuits are based on differential difference current conveyors (DDCCs) and operate in voltage-mode. The circuits use only one DDCC, two capacitors and two resistors. The notch filter configuration is related to the all-pass filter configuration by grounding one of the non-inverting and the inverting input terminals of the DDCC. SPICE simulation results are included to verify the theory.