A Naim design project group began reviewing the existing preamplifier designs exploring possibilities for major design improvement over the then existing reference preamplifier: the Naim NAC 52.
Many designs were explored and a complete evaluation of the current component and raw material situation took place. The circuit topology was totally reviewed and components upgraded in accordance with the advancements made over the last decade. Extensive listening to various designs and topologies ensured that the harmony between music and technology was maintained.
Power supply design has always been at the heart of Naim research and this project was no exception. For the NAC 552 a radical new split rail power supply configuration has been employed that almost eliminates power supply noise in the signal earth.
Housed in a separate, full-width brushed aluminium case, the power supply features a massive 800 VA toroidal transformer, three enormous smoothing capacitors and fourteen hand-selected power regulators to supply independently the different stages of the preamplifier. As pioneered in the Naim CDS compact disc player, fully suspended sub-chassis mounted circuit boards are used in the Naim NAC 552. This method of suspension maximises isolation, hence minimizing the effect of vibration on the highly sensitive electronic components.
Carefully selected precision rotary potentiometers with precious metal wipers are used to preserve music integrity and ensure long-term stability. Six inputs on the NAC 552 can be selected directly from either the front panel or the remote control. In addition to the usual DIN inputs, preferred for their superior earthing and impedance matching, the NAC 552 owner can configure two of the inputs for use with the more common RCA phono type connectors, enabling the use of alternative components with pre-owned interconnects.
Each of the six inputs has separate listen and record facilities. A dedicated unity gain input is provided for use with the Naim AV2 processor or similar. The Naim NAC 552 redefines the state of the art ensuring the utmost musical enjoyment for many years to come.