honestly, I think that this type of DAC - THD does not need to be measured
maybe it should, but I don't believe that it is possible to draw a conclusion comparable to conclusions such as when it comes to linear degree - if i have a stepped cube - sinusoid, at any frequency, how much THD do i think i get in the domain of linear measurement?
So what does it mean to measure THD 0.6% at 20kHz? The conclusion is that it sounds like my grandmother's tube Telefunken radio.
The problem is that on a DAC without a brickwall filter, you can't separate the THD you hear from the one you don't. This is a machine that wins on listening.
maybe it should, but I don't believe that it is possible to draw a conclusion comparable to conclusions such as when it comes to linear degree - if i have a stepped cube - sinusoid, at any frequency, how much THD do i think i get in the domain of linear measurement?
So what does it mean to measure THD 0.6% at 20kHz? The conclusion is that it sounds like my grandmother's tube Telefunken radio.
The problem is that on a DAC without a brickwall filter, you can't separate the THD you hear from the one you don't. This is a machine that wins on listening.
The quantified NOS DAC signal, without correction and modeling with a filter, is pointless to measure.
Measuring THD as proof of the quality here and character and envelope of the signal becomes pointless because we have a stepped signal.
Like when you show a photo to an impressionist fan. Full of unnecessary and irrelevant details, without the possibility to glimpse any philosophy of existentialism.
Measuring THD as proof of the quality here and character and envelope of the signal becomes pointless because we have a stepped signal.
Like when you show a photo to an impressionist fan. Full of unnecessary and irrelevant details, without the possibility to glimpse any philosophy of existentialism.
One part of the book "The Compact Disc Handbook (Ken C. Pohlmann) "- to show what we are doing here - all the opposite of theory and common sense.
We actually bring in all the possible and impossible harmonics......with no filter.
You can't hang the datasheet according to which this no filter DAC works. Even the protoboard for the PCM63P which has a simple 5 parts has a filter chip. No one understands how this really works, but it works. And what am I supposed to measure here when it is not according to the books.
This is Voodoo magic and I love the way it sounds.
We actually bring in all the possible and impossible harmonics......with no filter.
You can't hang the datasheet according to which this no filter DAC works. Even the protoboard for the PCM63P which has a simple 5 parts has a filter chip. No one understands how this really works, but it works. And what am I supposed to measure here when it is not according to the books.
This is Voodoo magic and I love the way it sounds.
Is that one of your diy NOS PCM63P boards you're referring to? I'm curious of what exactly you're alluding to there, is it to the sound of NOS in general? Thanks.Even the protoboard for the PCM63P which has a simple 5 parts has a filter chip. No one understands how this really works, but it works. And what am I supposed to measure here when it is not according to the books.
This is Voodoo magic and I love the way it sounds.
For No filter (filterless) DACs in general.All of them wasn't sine wave. Even if you have like @NIXIE62 transformers at the output is not a pure sine wave.
FFT measurements are not only for the trivial number of THD. That is maybe the last significant information. But harmonics order, denisity of HF noise, PSU main F impact etc. And in the range of frequencies. Also the same measurements of -60db. All that giving the sound signature and can be detected from the measurements. That is why the people using. And comparing with sound outcome.
...
BTW. Transformer is also the filter.
C in the OP amp fedback is also dreating a filter
input C in OP amp is also creating filter
etc
I dont know why that constant repeating of filterless filterless....
.
Try not to be confused with digital filter and analog filter...
...
BTW. Transformer is also the filter.
C in the OP amp fedback is also dreating a filter
input C in OP amp is also creating filter
etc
I dont know why that constant repeating of filterless filterless....
.
Try not to be confused with digital filter and analog filter...
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I believe I understand what you were getting at. Yes, the hidden biological filter of the human ear, while affecting all DACs, even OS, greatly benefits NOS DACs in particular. While we can’t directly see the suppression of that filter on a spectrum analyzer display, it still effectively reconstructs an audio DAC’s output signal. The question with the biological filters is whether the amount of suppression they provide is sufficient by itself. This largely depends on the person. The young and female have the best high-frequency hearing, while the not so young (say, above 40) and male have the poorest. Just the same, I have seen some listening reports by some not so young and male listeners, which indicated that NOS DAC sound was subjectively improved by adding a high-order passive output filter. Take such anecdotal reports for whatever they might be worth.
From an electronics engineering perspective, analog reconstruction filters are not good at providing high levels of stop-band attenuation immediately adjacent to a flat pass-band (with an extremely narrow transistion). That requires the performance of a ‘brick-wall’ digital filter to cleanly seperate the closely adjacent bands. The specification target of OS digital filters is to suppress the lowest reaching image-frequency to beneath the format resolution. For CD, that means down to around -100dB@22kHz. However, that doesn’t take in to account the additional ultrasonic attenuation provided by the ear, which can be substantial. I suspect, but I don’t know for certain, that high-order analog reconstruction filter response flatness and upper turnover placement, also parts quality and their value tolerance, are largely responsible for such filters sometimes being reported as sounding less than transparent. Not too surprisingly, and as I read you as concluding, the ear provides sufficient attenuation of ultrasonic image-bands to completely satisfy the requirements of human music listening.
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You need a dolphin to ask him if he hears disturbances in the force. Or a bat.
That’s what you might initially think, but many tweeters still show significant output as high as 30khz, and some even to 40kHz, on-axis of course. Most of the low-pass filtering of NOS is from the ear itself.
This Hiquphon soft dome is -5dB@30kHz, just for one example. I thought much as you, until I once examined some dome tweeter data sheets for data on tweeter attenuation of CD‘s ultrasonic image-bands, for a research study. While not common, such performance isn’t all that uncommon either. Not flat, but still significant in level, to my surprise.
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It is not about high frequency at all
(for 44.1K it is almost -3db@1/2Fs)
You dont need animals or pats with HF hearing capabilities...
but some HF atefacts that "transfering" from HF to the mid BW.
offcourse listening the "wrong" part of spectrum, can mislead the center point...
(for 44.1K it is almost -3db@1/2Fs)
You dont need animals or pats with HF hearing capabilities...
but some HF atefacts that "transfering" from HF to the mid BW.
offcourse listening the "wrong" part of spectrum, can mislead the center point...
I’m not clear on exactly what you are suggesting here, Zoran.It is not about high frequency at all
(for 44.1K it is almost -3db@1/2Fs)
You dont need animals or pats with HF hearing capabilities...
but some HF atefacts that "transfering" from HF to the mid BW.
offcourse listening the "wrong" part of spectrum, can mislead the center point...
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It's a small tweeter, it should have an even wider range. Room response will be much narrower don't forget that either. Larger dome tweeters 25/28mm will be good filters for ultrasonic sound in an average room.
HF noise will have some impact on electronics, for sure.