Audiophonics HPA-S400ET Review (Stereo Amplifier)

[Rja4000]

24-bit is needed to reach those SOTA SINADs, and I'm not convinced that anything better that 16-bit is needed for most of us. Archimago has done some blinded tests which I found fascinating <https://archimago.blogspot.com/2023/05/results-internet-blind-test-of-24-bit.html>.

Well, probably not... If you do everything well to keep that margin all over the chain.

If you have to lower level at -20dB, then it's likely only 60dB remains.
Which may become a bit short.

 

[Bob101]

I'm sure you're right, but might -90 dB even be a bit optimistic, especially for old 'uns like me? Is there any research on just how low this needs to be, depending on age, experience, etc.?

I agree, not only on THD+N, but just SNR should be considered too. My listening space is DAED quiet, and I recently had an amp with a stated SNR of -90dB and I could hear hiss when it was not playing any material. Not much, but enough to be annoyed
With my HPA SA400ET I hear nothing, ever, with my ears to the tweeter of any speaker.

 

[AudioSceptic]

I agree, not only on THD+N, but just SNR should be considered too. My listening space is DAED quiet, and I recently had an amp with a stated SNR of -90dB and I could hear hiss when it was not playing any material. Not much, but enough to be annoyed
With my HPA SA400ET I hear nothing, ever, with my ears to the tweeter of any speaker.

That -90 dB is below full output, and doesn't tell us the absolute level. Also, doesn't it depend on the frequency distribution: I would find a "hiss" much more audible than a "rustle" at the same level, for instance.

 

[mike70]

with a stated SNR of -90dB

Stated by who? At what conditions?

We need trusty measurements to make statements.