peterpan, here are some good posts on this forum on DACs.
https://www.diyaudio.com/forums/the...enge-bother-designing-dac-12.html#post6111566
https://www.diyaudio.com/forums/the...enge-bother-designing-dac-26.html#post6114633
https://www.diyaudio.com/forums/the...enge-bother-designing-dac-30.html#post6116370
https://www.diyaudio.com/forums/the...enge-bother-designing-dac-12.html#post6111566
https://www.diyaudio.com/forums/the...enge-bother-designing-dac-26.html#post6114633
https://www.diyaudio.com/forums/the...enge-bother-designing-dac-30.html#post6116370
So, why do you need a dac for CD play only? Don't you already have one? What do you use to play your cd's now?
It could occur both on the digital and on the analog side, but it is usually a strictly digital problem. See the site Mark referred to and the attachments.
For what it's worth, I've got a Tascam CD-200 that sounds OK by itself. To that I added a Cambridge Audio DacMagic 100 connected through a Toslink interconnect, and the sound improvement was undeniable. The audible noise decreased slightly, the depth and width of the stereo image was greatly enhanced. I shopped around and found both on discount, paid about $500 for both.
Mike
Mike
Did you listen both at matched level? If not, the difference you've noticed is likely due to the volume level differences.
I didn't attempt any direct comparisons...but I DEFINITELY hear more detail and improved imaging...a slight level difference won't affect those qualities.
Mike
How many decibel is slight? Also, where did you get the result that such level difference won't affect those qualities?
I forgot to mention that the zip file of post #24 contains a simple test to check whether a DAC can handle intersample overshoots.
I would like to highlight, what I suspect, is the important significance of an technical issue which Marcel's 'preechoes' PDF of post 24 addresses. Identified decades ago by Lagadec, et. al., I suspect that it still is an insufficiently appreciated issue in digital audio design. Just my suspicion.
The ripples discussed in Marcel's paper are frequency-domain ripples. Not time-domain impulse response ripples. They are uniform undulations in the frequency response produced by 'equiripple' digital anti-alias and anti-imaging filters. Equiripple filters are utilized nearly ubiquitously within commercial audio converter chip filters, for cost and ease of implementation.
The equiripple effect is clearly shown in the published frequency response graphs of most converter chip data sheets. These frequency-domain ripples indicate the presence of signal correlated time-domain echoes occurring within the digital filter. To be very clear, these are not the decaying, time-domain impulse response ripples we usually think of when discussing brick-wall filters, and which are commonly termed, 'pre-ringing' and 'post-ringing'. Equiripple behavior are not an inherent part of digital filter performance, being instead a function of a particular popular filter design algorithm.
As an aside, I have long wondered whether or not the absence such ripples in (NOS) filter-less DAC boxes are responsible for a large part of their non-fatiguing sound character.
The ripples discussed in Marcel's paper are frequency-domain ripples. Not time-domain impulse response ripples. They are uniform undulations in the frequency response produced by 'equiripple' digital anti-alias and anti-imaging filters. Equiripple filters are utilized nearly ubiquitously within commercial audio converter chip filters, for cost and ease of implementation.
The equiripple effect is clearly shown in the published frequency response graphs of most converter chip data sheets. These frequency-domain ripples indicate the presence of signal correlated time-domain echoes occurring within the digital filter. To be very clear, these are not the decaying, time-domain impulse response ripples we usually think of when discussing brick-wall filters, and which are commonly termed, 'pre-ringing' and 'post-ringing'. Equiripple behavior are not an inherent part of digital filter performance, being instead a function of a particular popular filter design algorithm.
As an aside, I have long wondered whether or not the absence such ripples in (NOS) filter-less DAC boxes are responsible for a large part of their non-fatiguing sound character.
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They may be one factor. There are other factors too. For example, the characteristic sound of the ESS PCM modulator and RF leakage out of SD dacs getting into downstream electronics are two that exist and that are hard to measure with an AP (small changes may be seen, but not that reflect the actual changes in audibility). No papers I can think of written about those two, perhaps in part due to all the NDAs people have to sign. Also perhaps in part due to much research remaining proprietary in today's world. Public funding of research into audio dacs is virtually non-existent. Assuming no NDA problem (maybe a big assumption), why would somebody publish something of potential value unless perhaps in hopes of more professional recognition leading a better paying job or something like that?
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The treble roll-off due to the zeroth-order hold function and the fact that they can handle intersample overs with no problems could also play a role.
That because it's a matured technology. Why waste money chasing something that's already audibly transparent. Would that be because they want to make it even further beyond audible range? Yeah, that would be a good sales pitch until it gets busted in level matched double blind test like those boutique DACs (Benchmark & Mark Levinson) have been.
We spend money making better dacs because they are not yet audible transparent. Properly conducted blind tests will show what I claim to be true. Amateur tests put together by EEs, technicians, and or hobbyists are meaningless. Those are designed to trick the victim into false negative results.
Oh FFS read my post, I told you literally everything I have to offer...I didn't measure anything. I DO hear more detail at ANY volume level, and I DO hear better sound stage imaging at ANY volume level.
Mike
Companies spend money making DACs with ever more impressive numbers for a few performance parameters, because they expect they can sell them and make a profit. Whether they are audibly transparent is irrelevant.
True, but not my point. That dacs are not yet transparent is why we (meaning people like me) continue to build dac boards from newer and better sounding dac chips as they become available. If dac chips were capable of being transparent then I would't waste my time after the first one.
Let me borrow your own line.
peterpan, just like I told you.
No worries.
Try this, listen to your favorite music through one DAC in your audio system, then change just the volume but nothing else and listen to the same passage again. You will hear a difference even though it's through a same DAC. Let that sink in for a while.
As soon as you will cough up the money to pay Jakob2 to do the testing, you will thereafter have your proof. Its expensive to do right, but not my problem. I don't need additional proof since I already know what the result will be.