SPL Mercury

We have looked at many converter designs and asked ourselves why innovations take place almost exclusively on the digital level and only very rarely on the analogue side. Perhaps it is because most developers have their background in digital technology and therefore tend to develop analogue technology according to the 'cookbook'.

We have 30 years of experience in analogue technology and we find cookbook designs rather boring, inefficient and in need of improvement.

The output of the DAC IC (AK4490) is an analogue signal that needs to be filtered with a low-pass filter. This analogue circuit is typically operated with the same voltage as the DAC IC - for example 5V. Imagine that the first stage that finds the analogue signal has a dynamic range and signal-to-noise ratio limited by this voltage. What a bottleneck.

In the Mercury, our 120V technology is used instead of the standard technology. And it does so twice in the newly developed DLP120 module. DLP stands for "Dual Low Pass". These are two separate analogue filters using 120V technology. Depending on the type of digital signal, the analogue signal passes through the PCM or DSD filter and can freely unfold into a huge dynamic range. This is audibly better.

The DA converter (DAC) in the Mercury is the AK4490 Velvet Sound® converter chip from AKM. This offers a bit depth of 32 bits and a maximum sampling rate of 768 kHz for PCM digital signals and DSD4 or DSD256 for direct stream digital signals.