A thermoacoustic transducer apparatus is disclosed including at least one thermal converter operable to provide power conversion between acoustic power and thermal power in a pressurized working gas contained within a working volume, a portion of which extends through the thermal converter. The thermoacoustic transducer is operable to cause a periodic flow in the working gas during operation. The apparatus also includes a reservoir volume in fluid communication with the working volume through a conduit having a working volume end in fluid communication with the working volume and a reservoir volume end in fluid communication with the reservoir volume. The conduit has a bore size and length operable to cause pressure oscillations at the working volume end to be converted to flow oscillations at the reservoir volume end such that periodic fluid flow at the reservoir volume end is at least twice as large as periodic fluid flow at the working volume end thereby facilitating a steady fluid flow along the conduit for equalization of working gas static pressures between the working volume and the reservoir volume while providing a sufficiently high acoustic impedance at the working volume end to minimize losses due to periodic flows of working gas within the conduit.