mocenigo

how to ruin a perfectly valid amplifier module :-)

About 20 years ago I made a comparison with optical s/pdif vs electric s/pdif vs AES with a SONY transport/DAC combo. The first one was clearly inferior to the other two, most likely due to excessive jitter in the interface, as the effect was that of a foggy halo “around” the sound and in general of an attenuation of the treble. There may be other aspects, but jitter is the most likely, followed by potential imbalance between electrically connected devices (so non-galvanically-isolated electric connections inferior to galvanic isolated ones) and these are today solved problems even in relatively inexpensive devices. The same cannot be said of many “high end” products: they are said to be “revealing” of other equipment choices and it is an easy thing to do by avoiding local solution of some issues - since this is the easiest way to achieve “revelatory” properties it is also the most likely. My reasoning is that if your DAC needs something like the intona to work well with your source then it is your DAC that is defective, and possibly also the source. If the band aid works, good for you, but I would remain with the doubt that the isolator does not solve the problem in full.

I agree. My “digitizing” comment was tongue-in-cheek.

I know. Quite gory :-)

ASR is not only Amir’s reviews. There are a lot of discussions which are scientific in nature — despite the fact that most visitors to the site are just interested in SINAD.

There are no tiny receptors in the hearing apparatus that are impacted by air molecules. There is a membrane moved by air pressure which is sensed by some bones, and these move the cochlea which is filled by a liquid that hits about 25000 nerve endings. It is the latter that in a sense “digitize” the signal.

WHOOOOOOOOOOSH!

Well, since all my sources are digital, I do listen to numbers :-)

we can say this. I would phrase it differently but I can agree that we agree. (Miska however interpreted some data in a misleading way. You are not reducing the resolution of a system to just 4 bits if the artifacts are not in the audible band. And even a 10khz artifacts does not mask a less loud 440hz sound.)

Do not misquote me. I did not write that it is absent. It is for audibility purposes. 12 hours ago, mocenigo said: Please do not reply out of context. I was referring to a NOS context. In that case at most you filter at 20khz and then you eliminate the components of the image between 22.05khz and 24khz. Not much.

Exactly, like crackles, pops, low frequency rumble, feedback, and a higher noise level overall!

I wrote more investment, i.e. there is some R&D that is more significant. The actual HW, including then analog filter, can be cheaper.

If am not mistaken this was a filter at 20khz. Which means that the first mirror image started at 24.1Khz, and then they had to use a steep analog filter. They moved quite quickly to 2x upsampling (so with the first image from 68.2khz, allowing for gentler analog filtering) but they started advertising the upsampling with 4x.

True. But the effect of ringing is overstated, in fact it is essentially absent from "true musical signal," or inaudible, as long as the source does not clip and is properly bandwidth limited. In fact, I never heard of a single study proving it is audible if these conditions are met.

Wow, I do not know where to start to unravel your confusion. So, digital filtering without upsampling will not remove the conversion artifacts, i.e. the images. They are a product of the conversion and they depend on the sampling rate. No processing of the signal will reduce them. I feared you were talking of digital filters, but I hoped you would not. The sigma-delta modulation is not to enable a "simpler, less expensive final analog reconstruction filter", it is a conversion process and in fact it requires a more significant investment analog reconstruction filter. What it does is that it makes the DAC cheaper and at the same time more precise (except the very first iterations which had problems such as potentially unbound settling times and the like). In fact there is a very profound difference.