Hi Alex,
You have to be careful with some of these numbers when making comparisons. Things like is it a 'weighted' or 'unweighted' measurement, is it 'dithered' or 'undithered' etc. So to be fair comparisons should probably be made with the same 'tester' and 'test gear' as opposed to comparing one magazines measurements with another.
That being said below are the measurements of the BDA-1 taken by the Australian Magazine Hi-Fi:
Test Results
Channel separation is excellent, with the BDA-1 returning a best result of 141dB at 1kHz, while the result of 113dB at 20kHz is one of the best I have seen at such a high frequency. The Bryston's overall signal-to-noise ratio was also excellent, with Newport Test Labs measuring 116dB A-weighted. This, too, is one of the best results I've ever seen from a DAC. One reason for these low noise levels is evident on the spectro-grams, where the noise floor continues flat right down to 0Hz, with no evidence of any mains noise creeping into the circuitry. Graph 1 shows a -10dB recorded signal, and you can see there are no harmonic distortion components visible above the noise floor at all. Also, the noise floor is sitting down at -130dB, which is a fabulous result! No wonder that overall THD+N was tested at 0.007%.
As for linearity, the figures tabulated in the table speak for themselves, with the Bryston delivering only imperceptibly small errors all the way down to the measurement signal limit of -90.31dB. Distortion performance at these low signal levels is excellent, as you can see in Graphs 3 and 4. You can seen that without dither (Graph 3), the BDA-1?s noise floor is lower than -140dB. Adding dither to the test signal sees the noise floor increase to -130dB, but as expected, the distortion visible in Graph 3 disappears entirely.
Steve Holding
