Audiolab 9000Q APx555 measurements – how good are its analog preamp and DAC sections?

[Negatywny]

Hi everyone,

I’m a measurement noob/enthusiast considering buying the Audiolab 9000Q, and I would appreciate some help interpreting the detailed APx555 measurements published by SoundStage:

https://www.soundstagenetwork.com/i...-measurements&option=com_content&view=article

My very tentative interpretation is that the analog preamp section measures exceptionally well, while the built-in DAC is good but not quite at the same level.

Some of the analog results:

• XLR analog, 4 Vrms in/out: approximately 117 dB A-weighted SNR
• Analog THD: below 0.00010–0.00015%
• Analog THD+N, A-weighted: below 0.00018–0.00022%
• RCA, 2 Vrms in/out: approximately 120.3–120.4 dB A-weighted SNR
• Crosstalk at 10 kHz: approximately –130 dB
• Frequency response essentially flat throughout the audible range
• Output impedance: 121 ohms RCA and 95 ohms XLR
• Maximum output before 1% THD+N: approximately 5.9 Vrms

SoundStage also states that the RCA inputs/outputs achieved approximately 9 dB better SNR and around 10 dB lower THD than the balanced connections. This seems rather unusual to me. Does it suggest that the RCA circuit is genuinely better implemented, or could it result from differences in test level, topology or the way the balanced circuit is measured? In a normal domestic system with short cables, would there be any reason to use XLR rather than RCA with this preamp?

The DAC results at 24/96 include:

• A-weighted dynamic range: approximately 120.8–120.9 dB
• THD: below 0.00094% left and 0.00044% right
• A-weighted THD+N: below 0.0011% left and 0.0005% right
• This corresponds to an approximate SINAD of better than 99.2 dB for the left channel and better than 106.0 dB for the right channel, calculated from the reported THD+N limits.

The DAC therefore appears noticeably less impressive than the analog line stage, particularly in distortion and the difference between channels. However, I am not sure whether these results are merely less “state of the art” or whether they indicate any realistic audible limitation.

SoundStage also reported that changing the reconstruction filters produced no measurable difference on their sample, as if the filter-selection feature had not been enabled.

I would be grateful for comments on the following:

1. Is the analog preamp section effectively transparent under normal listening conditions?
2. How good is the built-in DAC by current standards? Is it still comfortably transparent despite the weaker distortion results?
3. Are the differences between the two DAC channels meaningful or concerning?
4. Does the much better RCA performance indicate a weakness in the balanced implementation?
5. Are there any other weak points in the measurements, such as the approximately 5.9 V maximum output, 9.4 kΩ XLR input impedance, relatively coarse 1–2 dB volume steps, or apparently inactive DAC filters?
6. Would using an external DAC such as a Topping E50 into the Audiolab’s RCA input provide a meaningful measurable improvement? Would there be any plausible audible benefit, or would this mainly be measurement optimisation?

My current conclusion is that the 9000Q may be an excellent traditional analog preamp with a competent but less exceptional DAC built in. However, I may be reading the results incorrectly, so I would appreciate corrections and opinions from people who understand these measurements better than I do.

 

[Negatywny]

To clarify, the SINAD figures were not quoted directly by SoundStageNetwork. I asked AI to convert SSN’s published THD+N percentages into dB using:

SINAD = −20 log10(THD+N)

For example, 0.00022% corresponds to approximately 113.2dB, while 0.00025% corresponds to approximately 112.0dB.

Those THD+N figures refer to SSN’s primary balanced XLR analogue measurements. For RCA, SSN reported an A-weighted SNR of 120.3–120.4dB at 2V and stated that RCA produced approximately 9dB better SNR and roughly 10dB lower THD than XLR, but they did not publish a complete RCA THD+N result. Therefore, an exact RCA SINAD cannot be calculated from the published table. I may not have made that distinction clear enough in my original post.

Regarding phono: yes, I use a turntable, although I already own a Fosi Audio Box X5 phono preamp. I am therefore interested in whether the Audiolab’s built-in MM stage is good enough to replace it, rather than the phono input being an absolute requirement.