A new Dac to improve sound quality from Khadas Tone Board 1

[raindance]

But I do have some 48k, 96k and above tracks.... and I'm wondering how DACs really reproduce them.

Only bats care.... But seriously, most of this "high res" content does NOT contain anything other than noise over 20K even if it is theoretically possible. Mostly it is a scam.

 

[b4nt]

Yes, but the problem is that often there is nothing, or no musical content, above 22kHz (to be generous) in the source file as Amir has shown in several videos analyzing "Hi-Res" content.

Only bats care.... But seriously, most of this "high res" content does NOT contain anything other than noise over 20K even if it is theoretically possible. Mostly it is a scam.

I would say, depends. Tracks can be sold as being 96 or 192k but yes, with not much inside them, either limited to 20k, or with noise above 20k.

According to Speck, some tracks are more rich, go up to 25k or so.

 

[fieldcar]

Yes, but the problem is that often there is nothing, or no musical content, above 22kHz (to be generous) in the source file as Amir has shown in several videos analyzing "Hi-Res" content.

Yep. There are a bunch of reasons why Hi-Rez is a scam.

• Most Hi-Rez content has essentially errant and unrelated noise and distortion past 20KHz. Sometimes it doesn't even follow the music at all, it's just random noise with harmonic spikes. @amirm has explained this in a few of his youtube videos.
• Most Hi-Rez content above 20KHz is typically ~80dB lower than the pinna excitation range of 2-5KHz. Our ears' sensitivity to sounds over 20KHz requires volumes considerably higher than 100dB be audible. So, in the end, it's the quietest parts of the recording that our ears have the most trouble picking up. It's just useless info IMO.
• Most Hi-Rez content with elevated high frequency sounds can actually cause distortion in the audible bands. This can be audible near the distortion threshold of an amplifier, and may have the unintended effect of creating audible harmonic distortion in the audible bands.

Hi-Rez is useless. Redbook / 16-44.1 FLAC is my endgame.

 

[solderdude]

All DACs go kind of 'flat' to just under 1/2 sampling frequency (with proper filtering)
It's the recordings that are usually the limit.... well the used microphones usually are.

 

[Koeitje]

All DACs go kind of 'flat' to just under 1/2 nyquist (with proper filtering)
It's the recordings that are usually the limit.... well the used microphones usually are.

This so much, a lot of popular microphones don't even go up to 20kHz.

 

[b4nt]

I now still do not know how DACs output stages electronics behave at 20kHz and above, and how impedance mis/matches between a DAC and a amp may alter the sound, even at 20kHz and below.

 

[solderdude]

There are no impedance mismatches between DACs and amps. There is nothing to match.
Only some very rare (tube output or transformer output) DACs can be an issue or amps with unusually low input resistances.

A DAC that receives 44kHz will go up to 20kHz flat, with 96kHz it will reach 40kHz flat, with 192kHz files 70kHz flat may not be an issue.

 

[HappyMax]

I wouldn't want to be pedantic but ASR is full of personal opinions on the musicality of this or that device validated exclusively by one's own ears and not by reliable data.

For example on this page you can find several
https://www.audiosciencereview.com/...pping-d90se-review-balanced-dac.24235/page-49

So I would like to understand why you feel it is not correct to post personal opinions on sound quality when many users do it quietly.

 

[b4nt]

There are no impedance mismatches between DACs and amps. There is nothing to match.
Only some very rare (tube output or transformer output) DACs can be an issue or amps with unusually low input resistances.

I don't think input/outputs of DACs and amps are pure resistive. I have to find a review here again, of a DAC and a warning on that point.

 

[b4nt]

I had noticed that review, of SMSL SU-9 Balanced DAC:
https://www.audiosciencereview.com/forum/index.php?threads/smsl-su-9-balanced-dac-review.16150/

And output impedance versus frequency:
RCA: https://www.audiosciencereview.com/...t-impedance-rca-audio-measurements-png.84558/
XLR: https://www.audiosciencereview.com/...uptut-impedance-audio-measurements-png.84559/

Plus that mention: "Be sure your amplifier has an input impedance above 3.7k Ohm (10 to 1 ratio) for XLR output and half and 1.3 k for RCA."

 

[Veri]

I wouldn't want to be pedantic but ASR is full of personal opinions on the musicality of this or that device validated exclusively by one's own ears and not by reliable data.

For example on this page you can find several
https://www.audiosciencereview.com/...pping-d90se-review-balanced-dac.24235/page-49

So I would like to understand why you feel it is not correct to post personal opinions on sound quality when many users do it quietly.

Many users do it quietly. Sometimes it is just tolerated or ignored. I would expect it to be challenged more often than not though.

 

[raindance]

@b4nt - and the point? Those numbers are a total non issue for the vast majority of equipment out there. Most normal equipment has input impedance exceeding 10K. In fact 47K used to be the norm. It's trending lower though, I believe, in the interest of chasing lower noise. If you connect 4 subwoofers in parallel with a power amp, then you may have an issue with the unit you mentioned, but the issue will likely be some voltage division (less loud) and some loss of low bass, not exactly Armageddon or anything.

 

[b4nt]

but the issue will likely be some voltage division (less loud) and some loss of low bass, not exactly Armageddon or anything.

Are those variations perceptible? If one compares two DACs in his setup, may he percive differences?

I found that funy opinion, he mixed effects of impedances with cables characteristics: "To sum it all up, preamp output impedance contributes to the ability to hear differences in cables between preamps and power amps. A preamp with a high output impedance will give the user the greatest possibility to hear differences in cables. A preamp with a very low output impedance will make all cables sound essentially the same. To put it differently, a very low output impedance preamp will be immune to cable effects and a very high output impedance preamp will enable the audiophile to spend countless months and dollars searching out that elusive 'magic' cable. " https://www.lencoheaven.net/forum/index.php?topic=15150.0[/USER][/QUOTE]

 

[solderdude]

I had noticed that review, of SMSL SU-9 Balanced DAC:
https://www.audiosciencereview.com/forum/index.php?threads/smsl-su-9-balanced-dac-review.16150/

And output impedance versus frequency:
RCA: https://www.audiosciencereview.com/...t-impedance-rca-audio-measurements-png.84558/
XLR: https://www.audiosciencerevi120ew.com/forum/index.php?attachments/smsl-su-9-balanced-usb-dac-ouptut-impedance-audio-measurements-png.84559/

Plus that mention: "Be sure your amplifier has an input impedance above 3.7k Ohm (10 to 1 ratio) for XLR output and half and 1.3 k for RCA."

Looks like resistive 120 ohm RCA (which is pretty standard for a DAC) to me.
The variances for higher frequencies cannot possibly exist in real world. Let's call it measurement error.

As long as the amp doesn't have an input transformer (possible for XLR) I don't think 370 ohm out is really problematic.

 

[b4nt]

The variances for higher frequencies cannot possibly exist in real world. Let's call it measurement error.

I found this also strange. But I'm still wondering what might happen to signals at those higher but audible frequencies. People are often chatting about the difference they hear using new or other DACs, details may come from there.

High end Hegel HD30 was sold as for 0-50kHz (-3dB). Nagra DAC HD for 5-40kHz (+0 – 3 dB). Would their output stages sound different than our DACs featuring 20kHz max? Amplitude and impedance may vary, phase shift maybe also.

According to reviews I've recently seen here, amplitudes curves are now all flat from 20 to 20kHz. So what do those people hear and discuss about?

 

[solderdude]

People are often chatting about the difference they hear using new or other DACs

Sighted observations and or different filters being used or level differences (as in this particular case).

There are NO DACs that are limited to 20kHz... there simply are none. All current DACs can easily do 24/96.

According to reviews I've recently seen here, amplitudes curves are now all flat from 20 to 20kHz. So what do those people hear and discuss about?

Those reports are all sighted or not level matched.

 

[fieldcar]

different filters being used.

I've really struggled to hear any differences between the filters on my ES100 and D50S. I assume that while I have a few choices, none of them introduce severe enough audible range aliasing and blurring artifacts to become detectable by my ear. Though, my hearing craps out at 16KHz, so maybe I wont be able to hear it. What are your thoughts? Do you hear aliasing artifacts, and if you do, do they need to be an "improper" or "no" filter that doesn't properly apply a low pass filter to nyquist's critical frequency?

 

[solderdude]

Some slow filters and young folks can detect those differences.
Old farts like me can't, no matter how hard we try.
Our hearing rolls off before the filters do.

Whether or not aliasing things occur depends on the recording and the gear behind the DAC.

 

[b4nt]

There are NO DACs that are limited to 20kHz... there simply are none. All current DACs can easily do 24/96.

Not what the chips are able to decode. But what line outputs are able to produce, their bandwith could be limited, to some 20-20k, 10-30k... where 24/96 is up to 48k (or less, depending what is in the PCM data).

 

[b4nt]

To be more clear and basic. Topping D50s is 20Hz - 20kHz (+/-0.1dB). Where is it at 30kHz? At -6dB?

Would it reproduce 24/48 contents, which are above 20kHz? How does it compare above 20k against other DACs decoding 192 and higher or DSD data contents?