(02-Nov-2024, 13:37)Confused Wrote: Taking a look at the comparison table in the first post, it occurs to me that the Expert / Expert Pro range never achieved Devialet's claimed specifications when independently tested and measured. (this is not a criticism of the OP, who is clear in stating that this is data from Devialet's website)

Taking a couple of numbers:

Signal-to-noise ratio: 117db vs 133db
Output impedance: 0.0057Ω (1kHz) vs 0.001Ω

I can recall seeing various measurements of the Expert where the signal to noise ratio was measured somewhere in the range of 115dB to 118dB, depending on model and which input is used. Similarly, Paul Miller's (HFN) measurements of a D170 indicated an output impedance of 0.003 ohms. Both of these figures are nearer the the quoted Astra specifications, rather than for the Expert specifications specified by Devialet. I believe that the 133dB figure originally quoted by Devialet for the Expert Pro is a genuine figure, but it is achieved by measuring in a very narrow and selective way, rather than is accordance with industry norms.

This makes me wonder if the Astra is actually very similar to the Expert Pro in terms of raw measured performance, and the difference in the numbers is simply Devialet moving to providing more honest data, measured more in line with industry standard practice.

With all that said, the output impedance of 0.0057 ohms as quoted for the Astra is a theoretically "worse" figure than the 0.003 ohms figure independently measured for a D170 Expert.

Both numbers are very, very low, so I doubt this matters much in real world listening, but I am a little surprised in seeing a theoretically worse number for the Astra, when compared to a measured number for a similar product from two generations back.

There might be a good reason for this, maybe certain compromises in the new design and the Astra is actually the better performing amp overall? Or maybe the Astra is actually a step back? I think we would need a lot more data to be clear with regard to this point, and actually listening to one might also be informative.