LABORATORY TEST REPORT
Newport Test Labs measured the output voltage of the balanced outputs of the Bryson BCD-3 as being a bit over 4-volts (see the table for the exact voltages), with of course the unbalanced outputs coming in at half this voltage. The difference in voltage between the two channels put the channel balance at an outstandingly good 0.051dB. Channel separation was so good that the guys at the lab were asked to double-check their results, but they reported that they were right the first time: 150dB at 20Hz, 157dB at 1kHz and 137dB at 20kHz. I am fairly certain that those are the best results Newport Test Labs has ever recorded for a CD player.
Remember, too, that this is ordinary Red Book CD testing! Inter-channel phase was also outstandingly good, coming in at 0.01° at 20Hz, with a ‘worst’ result of just 0.81° at 20kHz. THD+N was a vanishingly low 0.002% at 1kHz at 0dB and the distortion spectrum is shown in Graph 1. You can see there’s a second harmonic distortion component at –118dB (0.0001%), a third at –95dB (0.0017%) and a fifth at –123dB (0.00007%). That’s it! What’s more, the overall noise floor is sitting down at –140dB, with the low-fre- quency noise at the extreme left at around –120dB. If you look at the tabulated results, you’ll see that Newport Test Labs measured the overall signal-to-noise ratio at 116dB unweighted, and 123dB A-weighted. This means the Bryston BCD-3 is going to be a lot quieter
than any electronics you use to amplify its signal. At a recorded level of –10dB, which is more like what will be peak level on a typical commercial CD, only two harmonics are visible, a second at –132dB (0.00002%) and a third at –112dB (0.00025%). The low-frequency noise has dropped a little, so even that little noise at 0dB was likely caused by the maximum signal level… which would not be present on a commercial CD.
At –40dB recorded level, there’s no harmonic distortion visible at all, just ‘grass’ on the noise floor because of the lack of dithering on the 1kHz test signal. (If the signal had been dithered, the ‘grass’ would disappear.) You can see this on Graph 6, which shows the Bryston BCD-3’s response to an undithered 1kHz test signal recorded at –91.24dB compared to Graph 7, which shows the Bryston’s performance with a dithered 1kHz test signal at –90.31dB. The distortion components disappear entirely, and the noise floor becomes uniform across the audio spectrum… though slightly higher in level. However, since that noise floor is still sitting down at –140dB, it’s not an issue. You can read an excellent article about dither at www. tinyurl.com/magic-dither.
Newport Test Labs measured intermodulation distortion (IMD) using two different techniques, CCIF (Graph 8) and SMPTE (Graph 9) and the Bryston BCD-3 returned superb results in both cases. On Graph 8 you can see the two test signals at 19kHz and 20kHz around the centre of the graph. There are only two sidebands, both down at around –105dB (0.0005%) and the unwanted 1kHz difference signal is down even further at –126dB (0.00005%). The signals above 20kHz are IMD products related to the sampling frequency, but other than one at –117dB (0.00014%) they’re all 120dB (0.0001%) or more down. All these IMD products would be completely inaudible. On Graph 9 the test signals are at 60Hz and 7kHz (in a 4:1 ratio) and you can see some sidebands on the 60Hz signal that are around 110dB (0.00031%) down, plus some distortion around 16kHz that’s more than 120dB down (0.0001%). As I said: superb results.
The Bryston BCD-3’s frequency response is shown in Graph 10 and even a cursory glance shows that it’s ruler flat, particularly when you realise that the vertical scale of the graph has been expanded so far that each horizontal division represents a difference in level of only 0.2dB. This means the response is within 0.01dB of reference up to 5.2kHz, after which it ‘rolls off’ to be down 0.21dB down at 20Hz. So normalised, the frequency response measured by Newport Test Labs was 20Hz to 20kHz ±0.11dB. In other words, superb. The response below 20Hz is not shown on this graph, but it extends equally flat all the way down to 2Hz (the lab’s measurement limit).
The Bryston BCD-3 showed some slight de-emphasis errors (0.16dB at 1kHz, 0.84dB at 4kHz and 0.34dB at 16kHz) but these are small and no compact disc manufactured in the past 30 years will be emphasised anyway, so de-emphasis would not be required. If anything, Bryston is to be congratulated for including a de-emphasis circuit at all—many modern CD players don’t have one.
Linearity errors were very low, as you can see from the tabulated results, with no error at all at –60dB and –70dB and a worst-case error of just 0.11dB, at –80.70dB. This means sounds will be reproduced at the correct level, according to their recorded volume.
Impulse testing showed that the AKM DAC appears to use a minimum-phase reconstruction filter, so there’s no pre-ringing at all—all the ringing occurs after the impulse. The square wave shows identical performance.
The quality of the signal from the digital outputs was outstanding, with ultra-low jitter, at just 1.5 nanoseconds (peak-to-peak) and excellent eye-narrowing characteristics at both 200mV and zero-cross.
Power consumption when the Bryston was playing was about what I’d expect for a CD player, but the standby power consumption of 2.07-watts is about twice what I’d expect from a modern hi-fi component, with the Australian government expecting standby consumption to be less than 0.5-watts. That said, 2.07-watts isn’t going to impact on your power bills, but to be green, you should turn the player off when you’re not using it.
Overall, superb performance from the Bryston BCD-3 CD player. This is a state-ofthe-art component. Steve Holding