[Rob Watts]

My advice is to keep the source as simple as possible, so stick with what you have. Adding an extra stage (USB to optical) adds more complexity, more capability to increase RF noise, and more problems with ground (or mains) loops. When people report better sound quality, I have felt the explanation is simple increase in RF noise, thus more noise floor modulation in the DAC, and a brighter SQ - easy to confuse it with improved transparency. It's not more transparent, it just gives that impression due to the increase in brightness. The flatter sound-stage also give the impression of improved width; wider perceived width is due to a deterioration in sound quality.

Edit: as a postscript, a thought occurred to me about the importance of noise. As readers will know, I use the APx555 test gear; it's a big step up from previous Audio Precision. But recently I replaced my MSI lap-top with a Dell lap-top as my main design PC. You need to use a lap-top to run the APx555, and I dropped in the Dell as the MSI was going into retirement.

But measurements were considerably worse - around 2dB THD and noise using the Dell. Going back to the MSI restored the measured performance - this just indicates that RF noise and ground loops have definite measurable consequences, and this is the part of the measurement system that is just collecting and processing the data, it's not analogue at all.

So the MSI is out of retirement now and just used for running the AP...

 

[musickid]

Many thanks Rob. That really clarifies and puts things into perspective. Simple is best for sure.

 

[ZappaMan]

My advice is to keep the source as simple as possible, so stick with what you have. Adding an extra stage (USB to optical) adds more complexity, more capability to increase RF noise, and more problems with ground (or mains) loops. When people report better sound quality, I have felt the explanation is simple increase in RF noise, thus more noise floor modulation in the DAC, and a brighter SQ - easy to confuse it with improved transparency. It's not more transparent, it just gives that impression due to the increase in brightness. The flatter sound-stage also give the impression of improved width; wider perceived width is due to a deterioration in sound quality.

Edit: as a postscript, a thought occurred to me about the importance of noise. As readers will know, I use the APx555 test gear; it's a big step up from previous Audio Precision. But recently I replaced my MSI lap-top with a Dell lap-top as my main design PC. You need to use a lap-top to run the APx555, and I dropped in the Dell as the MSI was going into retirement.

But measurements were considerably worse - around 2dB THD and noise using the Dell. Going back to the MSI restored the measured performance - this just indicates that RF noise and ground loops have definite measurable consequences, and this is the part of the measurement system that is just collecting and processing the data, it's not analogue at all.

So the MSI is out of retirement now and just used for running the AP...

Were both laptops using an optical output ?

 

[HeeBroG]

Hi Rob.

Unfortunately not all music I like is available in PCM.
Some companies are transferring the original analog recording to DSD64.
Thereafter they create higher bit rate DSD128/256/512 files and term the process "re-modulations" (see below)
I wonder as DAVE/BLU2 plays DSD as DoP whether it is adequate to just purchase the DSD64 files and let the BLU2 do the upsampling?

G

"The reason we generate these additional delivery formats and DSD bitrates is to provide customers purchasing alternatives tailored to their DAC's design capabilities.

It is correct that there's no additional music content information contained in the higher DSD bitrate deliverables from the original DSD bitrate. What's different is the uncorrelated modulation noise content placement in the frequency spectrum. When a DSD original file is converted to DXD (PCM), the inherent DSD modulation noise is removed through the decimation filtering, and reoccurs when modulated back to DSD. The modulation noise (again, uncorrelated) is the carrier part of the DSD bitstream modulation, and an inherent part of the DSD bit stream.

While the modulation envelope spectral shape is the same regardless of the DSD bitrate, its effective frequency start and end points move an octave higher for every doubling of the DSD bitrate. For DSD64, the uncorrelated modulation noise is about -110dB at 20KHz, rising to about -50dB at 100KHz. For DSD512, the modulation noise is about -110dB at 160KHz, and -50dB at 800KHz. This allows the customer's DAC to use gentler, more Gaussian shaped reconstruction filter algorithms, with far improved phase response, yielding a more analog sounding, more spacious and detailed playback."

-- by Tom Caulfield, NativeDSD Mastering Engineer

 

[Rob Watts]

Were both laptops using an optical output ?

For controlling the APx555? That's done with USB. The signal outputs mostly uses AP's optical output, so the lap-top is merely controlling and displaying the data via USB to the APx555.

Hi Rob.

Unfortunately not all music I like is available in PCM.
Some companies are transferring the original analog recording to DSD64.
Thereafter they create higher bit rate DSD128/256/512 files and term the process "re-modulations" (see below)
I wonder as DAVE/BLU2 plays DSD as DoP whether it is adequate to just purchase the DSD64 files and let the BLU2 do the upsampling?

G

"The reason we generate these additional delivery formats and DSD bitrates is to provide customers purchasing alternatives tailored to their DAC's design capabilities.

It is correct that there's no additional music content information contained in the higher DSD bitrate deliverables from the original DSD bitrate. What's different is the uncorrelated modulation noise content placement in the frequency spectrum. When a DSD original file is converted to DXD (PCM), the inherent DSD modulation noise is removed through the decimation filtering, and reoccurs when modulated back to DSD. The modulation noise (again, uncorrelated) is the carrier part of the DSD bitstream modulation, and an inherent part of the DSD bit stream.

While the modulation envelope spectral shape is the same regardless of the DSD bitrate, its effective frequency start and end points move an octave higher for every doubling of the DSD bitrate. For DSD64, the uncorrelated modulation noise is about -110dB at 20KHz, rising to about -50dB at 100KHz. For DSD512, the modulation noise is about -110dB at 160KHz, and -50dB at 800KHz. This allows the customer's DAC to use gentler, more Gaussian shaped reconstruction filter algorithms, with far improved phase response, yielding a more analog sounding, more spacious and detailed playback."

-- by Tom Caulfield, NativeDSD Mastering Engineer

Yes best to stick too DSD64 rather than DSD64>DSD128/256/512>M scaler>Dave as re-modulating DSD comes at a big price in loss of transparency and transients precision. Moreover, I have yet to see a better DSD filter than the one in the M scaler - it eliminates everything above 88.4 kHz.

 

[HeeBroG]

For controlling the APx555? That's done with USB. The signal outputs mostly uses AP's optical output, so the lap-top is merely controlling and displaying the data via USB to the APx555.



Yes best to stick too DSD64 rather than DSD64>DSD128/256/512>M scaler>Dave as re-modulating DSD comes at a big price in loss of transparency and transients precision. Moreover, I have yet to see a better DSD filter than the one in the M scaler - it eliminates everything above 88.4 kHz.

That's great. Thanks.

Geoff

 

[Ragnar-BY]

I`ve purchased a lot of albums from NativeDSD and here are my 2 cents. There are different type of recordings for sale.

Albums like this: I GOT THE T-BONE WALKER BLUES (2004)
were recorded to analog tape and than transferred in DSD64. DSD128, DSD256 and DXD is made by "remodulation" and to my ear there is no sense in buying DSD256 or 128. DSD64 in this case sounds the same, or even better.which are actually recorded in DSD256 or DXD

But there are also albums like this INSIGHT (2019) or this REFLECTIONS (2016) which are actually recorded in DSD256 (Insight) or DXD (Reflections). And in this case highest bitrate sounds much better than DSD64 or 24/96 versions.

With DSD256 and DXD M Scaler makes less difference than with CD, but effect is still there and overall result is outstanding.

 

[musickid]

Hello Rob,

I'm trying to set up an audition with the aeon 2. Assuming both open and closed models fit me well and not taking into account where i will be using them do you recommend the closed or open model? thanks again.

 

[Rob Watts]

I haven't heard the open Aeon 2 but my needs for headphones are for closed. The benefit of open is you don't tend to get the distortion in height - things sound slightly elevated with closed due to early internal reflections - not that that bothers me much anyway. I got the feeling that open tend to have a leaner SQ, so see which one suits you best by listening.

 

[flyte3333]

Adding an extra stage (USB to optical) adds more complexity, more capability to increase RF noise, and more problems with ground (or mains) loops.

Hi Rob, can you please clarify the quoted?

You have USB to optical in brackets and then mention RF noise and ground loops... but optical is immune to these, no?

Even with a USB to optical converter?

Cheers

 

[musickid]

Hello Rob,

Simply put is it okay to use optical out of a computer into HMS if that same computer has a wired ethernet connection?

(Optical is galvanically isolated so no potential problems AFAIK but you once mentioned capacitive coupling? My computer outputs optical into HMS but also has a wired ethernet connection for roon).

many thanks mk.

 

[ZappaMan]

Maybe the RF becomes airborne, so having more electronics generating protons in proximity to sensitive analogue components, could impact, even if the devices are only connected via optical, there is still an ambient transfer.
This should be measurable.
I would like to understand more how rf can or cannot increase noise floor modulation.

 

[iDesign]

Hello Rob,

Simply put is it okay to use optical out of a computer into HMS if that same computer has a wired ethernet connection?


(Optical is galvanically isolated so no potential problems AFAIK but you once mentioned capacitive coupling? My computer outputs optical into HMS but also has a wired ethernet connection for roon).

many thanks mk.

https://www.head-fi.org/threads/hug...official-thread.885042/page-481#post-15011215
The iMac is fine for you but the inexpensive Cirrus Logic S/PDIF audio controller in your computer is limited to 192 kHz and there are sources that are significantly better with much lower noise, much. As I previously recommended, you should utilize Audirvana+ with the SysOptimizer Extreme setting enabled for best performance because it can improve the playback performance on a Macintosh by 1. increasing the priority of Audirvana+ during playback to maximize the precision of the audio streaming and 2. deactivating all other resource intensive background operations that create activity on the disks which theoretically produce noise and interference. You need to trust your own ears and listen to other high end sources to appreciate the differences.

I do not use computers as my primary source but in light of your post, I should note that I previously compared the optical output of my mid-2015 MacBook Pro 15" to the USB-C output of my late-2019 MacBook Pro 16". The newer computer is audibly better and is it down to USB-C vs optical? No, it has as much to do with other improvements in the newer computer which is a BTO i9 2.4GHz, 64GB DDR4, and 5500M spec.

 

[Currawong]

The reality is that Dave and Hugo 2 have more than enough power to drive any headphone - except perhaps one or two very exotic models.

About the Hugo 2's output stage: It's stated as being Class A. I just wanted to clarify if it was Class A all the way through to maximum power output or if it goes into Class AB at some point.

Yes best to stick too DSD64 rather than DSD64>DSD128/256/512>M scaler>Dave as re-modulating DSD comes at a big price in loss of transparency and transients precision. Moreover, I have yet to see a better DSD filter than the one in the M scaler - it eliminates everything above 88.4 kHz.

If you had DSD256 or DSD128 files and decided to convert them into PCM, do you have any suggestions as to what software and what settings to use for doing so? I'm asking as while I'm reasonably good at comprehending information about digital music, helped quite often by your posts, many aspects of DSD don't make sense to me, such as how it is possible to have varying levels of volume in music which is only 1 bit.

 

[Rob Watts]

Hi Rob, can you please clarify the quoted?

You have USB to optical in brackets and then mention RF noise and ground loops... but optical is immune to these, no?

Even with a USB to optical converter?

Cheers

Of course optical will stop RF noise from entering the DAC via the digital input. But if you are using a mains powered USB to optical converter, then RF noise will form a loop from the source, via USB, and back to the mains via the converter. So now we have RF noise circulating around your mains; and this will either directly, or indirectly with capacitance, create RF ground currents. Now when you plug in your DAC, that could intersect this current loop, and so see the noise. Whether it's significant or not will depend upon the RF isolation on the DAC, and how the DAC is connected to the mains too. It's one reason why adding extra boxes from your source is not a good idea - keep the source as simple as possible. But I stress this is a possibility; so if you have such a device, then give it a try - the warmer SQ with the better depth is the option to go for.

Hello Rob,

Simply put is it okay to use optical out of a computer into HMS if that same computer has a wired ethernet connection?

(Optical is galvanically isolated so no potential problems AFAIK but you once mentioned capacitive coupling? My computer outputs optical into HMS but also has a wired ethernet connection for roon).

many thanks mk.

I can't see that as a problem. But if you are worried, listen to it with the Ethernet disconnected... Note Ethernet has galvanic isolation, but there will be capacitance coupling through the isolators, so it's not 100% guaranteed perfect isolation.