DAC Manufacturer Aversion To External DSP

[Miska]

18 hours ago, bobflood said:

The Holo Spring 2 DAC and May DAC are pretty close to that ideal. The Dennefrips are also on that list.

 

Disclosure, I own and love a Holo Spring 2 KTE.

 

And you can also consider T+A into similar category. They have their own filters for PCM side - that can be bypassed if you like. And separate pure bit-perfect discrete DSD side. They now even have built-in DSD1024 capable NAA in the SD(V) 3100 HV.

 

For my development headphone rig, I'm now testing the HA 200 headphone amp / DAC.

 

[Miska]

If one counts in companies who make chip based DACs that have some kind of direct/bypass possibility for the input data, there are many options. Two common features is bypassing digital filters with high rate PCM inputs and/or possible NOS mode, and DACs that have direct DSD conversion possibility. Some examples of such are RME ADI-2, TEAC and iFi.

 

 

How/if DAC manufacturers communicate about possibilities of external processing differs a lot.

 

[Miska]

4 minutes ago, barrows said:

Jussi:  It appears that the newer T+A DACs use the new Thesycon U-HEAR USB receiver code.  Developers at Thesycon have confirmed that this code works with Native DSD to 1024 on Linux.  Can you confirm that the HA 200 works on Linux for Native DSD at 512 and 1024? 

 

It works the same as Holo Spring 2 for example and I believe Denafrips as well. DSD512 should work with any relatively recent Linux and DSD1024 works at least with my kernel builds.

 

[Miska]

3 hours ago, 4est said:

Furthermore, PCM to PCM upsampling does not require a lot of processing power.

 

Most if not all PCM to PCM cases can run on my fanless light cheap laptop that has Pentium Silver N5000 CPU. It has 6W TDP and essentially is a quad-core Atom. It is my "travel email laptop" because it has 8+ hour battery lifetime and very light weight. Running Linux Mint.

 

[Miska]

1 hour ago, sandyk said:

 And PCM to DSD ? I would expect that the majority of purchasers of your S/W would want it to do PCM to DSD conversions. Besides which , judging by the recent 500 participant survey results, most Audiophiles  are unable to reliably hear the difference between16/44.1 and high res anyway under non sighted conditions.

 

At lowest to DSD256 on similar quad-core Atom. And then it is already way better than what you find inside DAC chips.

 

1 hour ago, sandyk said:

Besides which , judging by the recent 500 participant survey results, most Audiophiles  are unable to reliably hear the difference between16/44.1 and high res anyway under non sighted conditions.

 

And is the 16/44.1 through a non-oversampling DAC really running at 16-bit resolution at 44.1 kHz conversion rate? No, it is not. So you are talking about something entirely different.

 

[Miska]

7 minutes ago, sandyk said:

 No we aren't talking about different things. Most people comparing 16/44.1 with high res would be using DACs that internally upsample.

 

Yes, and we are now talking about internal upsampling vs external upsampling. Not about redbook vs hires.

[Miska]

2 hours ago, Albrecht said:

Is there anyone who would spend $20K on a Meitner and plug in a Belden USB cable from a MacMini on their audio rack?

 

What's wrong with Belden USB cable? Not that I have one. But I have Deltaco's USB HiSpeed certified cables. I still haven't seen certified "audiophile" USB cables. Many strange cable implementations outright violate the signal integrity and USB cable specifications, but cost a lot while doing so.

 

[Miska]

Just look for this badge:

[Miska]

3 hours ago, barrows said:

Just remember, that this mark is a trademark.  This means that any company displaying this mark is paying for it, and adding that cost to the cable.  And some company which does the "certification" is likely getting a lot of money for it.

 

Yes, of USB-IF, it is trademark to avoid people from randomly slamming it on something that has not passed the specified tests. Same goes for many other things like DLNA. Certification processes is not so different from FCC or similar... Or if you want to back yourself in electrical safety for CE marking, something like TÜV or FI approval. Similar approval / certification processes also apply to devices like mobile phones.

 

The certified cables I have cost between 10 and 20 EUR, so I don't hugely mind if part of the cost goes to the certification process. But when the cable has that badge, you know it complies to certain set of specifications.

 

[Miska]

1 hour ago, barrows said:

What makes you sure that a USB cable bearing that badge actually meets the specification?  Are the cables individually tested and certified?  I would think not.  Given that many USB cables, bearing that certification, are manufactured in China, where I have had direct experience of cable manfacturing errors and outright scams (the sample cable for testing meets spec, but the subsequent production run cables do not), I would not be surprised if some cables bearing that  badge did not meet spec.

 

It is at least likely because the design has been tested to comply. Having proper QA is another matter.

 

iPhones are also made in China, as well as lot of other stuff.

 

1 hour ago, barrows said:

I think it is possible that some "audiophile" USB cables which meet the performance spec (bandwidth and impedance) but do not comply with the construction spec, may perform even better sonically.

 

I have Supra USB cable, but what I've tested I failed to hear any difference to a certified cable. So it is now in a storage box unused.

 

It is easy to get normal USB cable with ferrite beads, or have correct type of snap-on ferrites added on normal cable. For my Supra it is not possible because the outer dimensions are not standard. Almost all of my audio use USB cables have ferrites, except USB3 cables (Holo Audio and iFi gear, etc).

 

But I try to stick to objective measures. I'd be curious to see technical explanation what aspects and how they make it perform better sonically and/or measurements from the DAC output that show this difference.

 

[Miska]

13 minutes ago, barrows said:

Yes, me too!  I hear differences in USB cables, and these are distinct enough that once I know the difference, I can pick them out blinded as well, so the differences exist.  It is maddening, but true nonetheless.  I suspect it has mostly to do with how the signal and noise is interacting with the USB receiver.  Only with poorly designed DACs have I ever heard of any analog DAC output measurements which confirmed the differences in cables, but the differences in sonics are still there with well designed DACs (properly isolated USB inputs, etc).

HiFi News tested some audiophile USB cables a couple of times, and found correlation between listening tests and high precision eye pattern testing, I wish someone would do more testing like this.  I would really like to see really high precision spectrum analysis of the ground, power, and data lines, and of the ground plane on the USB receiver board with different cables. Maybe we would something!

 

I'm looking at the DAC output, that's what you are listening. Not eye patterns on data cables, those are only useful for debugging problems.

 

But I'm not into audiophile data cables. My data cables are standard things, USB cables are certified, and ethernet cables are also typical IT gear. I have some 10+ HQPlayer servers and some tens of DACs. Not going spend horribly lot of money playing with data cables on such. I get the objective DAC output performance I want with standard cables with ferrites. When all or most of the cabling is the same throughout all gear, comparing things head-to-head is also easier.

 

My analog cables are Supra, in analog domain cables make more difference. And I agree with Supra design philosophy of minimizing capacitance on interconnect and minimizing inductance on speaker cables. And these are not horribly expensive either, and are made in neighboring Sweden.

 

 

P.S. I think this thread has drifted horribly off topic...

[Miska]

23 minutes ago, R1200CL said:

Should manufacturers more use ethernet as signal in ?

What’s the benefits over USB as an example.  It seems to me USB creates support issues, will use of Ethernet remove those issues as one example ?

 

That's one option, but very likely it will generate more support issues.

 

25 minutes ago, R1200CL said:

Will HMDI as transfer technology be a better option than USB ?

Or shouldn’t manufacturers at least incorporate a HMDI interface from your TV or player.

 

HDMI is bad for audio, because you need to send picture always (black picture is enough though), and possible audio formats depends on the video resolution. In addition, audio clocks are based on the video pixel clock. So it is really only good when used for audio for video as it is intended to be used. Not really as an audio interface.

 

2 hours ago, R1200CL said:

Will Ethernet to SPDIF converters be something that will better keep many of us using our old DAC with no USB interface, or poor usb interface be something to consider.

 

Such can be useful, especially if you want to remotely access the DAC.

 

2 hours ago, R1200CL said:

And will this device still need support for RAAT and NAA, which I guess also mean a simple web interface, unless one create one Ethernet input (fiber) for each option ?

 

Could be one possibility. This can be implemented easily for example using RaspberryPi and HifiBerry Digi+ Pro.

 

2 hours ago, R1200CL said:

Am I correct that there is a consensus that volume control done right, now can be handled in the digital processing ?  And maybe even better than most preamps ?

 

Digital implementation can certainly beat preamps (or well, pre-atts to be accurate).

 

[Miska]

1 hour ago, barrows said:

Both Ethernet and USB allow for any sample rate, which is an advantage as far as I am concerned.

 

USB is quite capable, but USB Audio Class is not. For example you cannot make standard compliant 8 channel interface that is capable of 705.6/768k PCM or DSD256 with USB Audio Class.

 

1 hour ago, barrows said:

IMO the best option, if done well, is an optical Ethernet interface, with no sample rate limitations, and supporting all the relevant protocols (DLNA, RAAT, and NAA).

 

Nitpicking here, but I would say UPnP AV, RAAT and NAA. DLNA (one of those certification trademarks) is not really good for the purposes we talk about.

 

[Miska]

Just now, barrows said:

Yes, but USB is currently available, and optical ethernet in a DAC is in its infancy.  It will be quite a few years before we see really well implemented optical Ethernet interfaces become any kind of standard in DACs.  Right now there is one DAC with this I ma aware of.  

If i was developing the proposed DAC for commercial release, it would have a modular input section, and the customer could choose between optical ethernet and USB inputs at purchase.  The requirements would be to support up to DSD 1024 and for ethernet, DLNA, RAAT, and NAA.

 

Copper ethernet is also way better than USB anyway. It doesn't need to be optical to beat USB.

 

Why restrict to DLNA, why not UPnP AV? I'm personally not interested in DLNA, but only in UPnP AV.

 

[Miska]

31 minutes ago, R1200CL said:

I would still like to understand why HMDI shouldn’t be implemented as an interface for DACs, as I like my DAC to be used in conjunction with TV or TV boxes. I would prefer HMDI in and out, so after my DAC has collected sound, the signal can go to TV. (Or even another multichannel DAC).

 

Well, it can, and some DACs do. For example the T+A HA 200 headphone amp I'm using now has option for HDMI input board. And it can be useful when used for audio with video. But since HDMI is completely video driven interface, it is not so great for audio-only.

 

It is expensive thing to do in low production volumes though, so it will add quite some cost.

 

1 hour ago, R1200CL said:

Can the SACD be up sampled in the external PC, and signal sent over Ethernet?

(Not ripping, but you insert it in the drive of your PC, assuming there is SACD drives on the marked).

 

Since there are no SACD drives available, it cannot be played directly from a computer.

 

You need to rip SACD and then you can play it upsampled in PC and sent over Ethernet. This is what I'm doing. But I would say as physical format, SACD is almost dead now. DSD downloads are alive and doing well, and at higher rates like DSD128 and DSD256.

 

[Miska]

8 minutes ago, R1200CL said:

My other idea is that in theory, one should be able to rent space (and processing power) in a data center, add Roon and HQPlayer, and use VPN technology to your home. A CAPS seems to be quite expensive, so maybe price won’t stopping you from such approach.

 

It is doable, but data center power is not cheap either. So after all it likely wouldn't be any cheaper for you.

 

DSD512 would take constant 50 Mbps streaming and DSD1024 would take constant 100 Mbps. Not so much problem with current gigabit fiber internet connections, but still notably more than current approach.

 

[Miska]

3 minutes ago, R1200CL said:

@Miska

This isn’t possible today or ?

 

It is, HQPlayer 4 Pro is for that purpose.

 

But down side is that it takes a lot of time to convert files, it takes a lot of space, and if you want to change conversion settings you need to redo conversions. And of course it won't work for streaming services like Tidal or Qobuz.

 

OTOH, that allows you to use EC modulators for DSD512 or DSD1024...

 

[Miska]

8 minutes ago, Albrecht said:

HDMI connectors can be used for many things. HDMI is not a protocol but a piece of hardware. 

 

HDMI is pretty strictly defined standard for transporting video and piggybacking audio on top of video (in vertical refresh isles in the data stream). It defines exactly how audio clocking is done, what audio formats are supported and how much audio data can be sent with certain video resolutions. And how to calculate audio clocks from the video pixel clock. I have HDMI specification documents and I have read through those.

 

Use of HDMI connectors and cabling for LVDS I2S has nothing to do with HDMI whatsoever.

 

[Miska]

Just now, Albrecht said:

As i wrote....

 

But it is certainly a protocol over data transport link, with handshakes and everything. I would say more complex than for example USB.

 

[Miska]

6 minutes ago, Albrecht said:

Just like hardware, (which is prolly something like 80 to 90% of any SQ), that should be addressed first IMO.

 

With modern delta-sigma converters, DSP side plays major part of the performance. The whole idea is to simplify hardware side by moving as much as possible to digital domain processing where you are not restricted similar way as hardware/analog world is. By doing DSP in software using computer you already have, the hardware money can be spent on parts where it really matters instead of putting major part of it into building a resource constrained computer into a DAC.

 

[Miska]

2 hours ago, Albrecht said:

On this earth, - there's no way to make a Schiit sound like a Meitner, - (even 25 year old Meitners), - unless you go waaaaaaay down into BoomBox-style associated equipment.

 

Because of the above, IME, - this does go down to DAC processing too, - (i guess in a little contradiction to what I said above). In that, - I've never heard any Sabre DAC implementation sound "right." And, - I do believe that it is possible to make a Sabre chip(s) sound right with processing and really good output stages, and power supplies, - all things being equal, - DACs with Sabre chips don't sound right compared to AKM and other implementations. 

 

And AKM, or TI/BB chip works soo much better when you bypass it's DSP section and run it straight as plain converter with external processing.

 

But then again you can go for DAC implementation that doesn't have a DSP section. Meitner could be much better for the same price, or much cheaper, if the DSP section is omitted and only D/A section left.

 

1 hour ago, Albrecht said:

And to that. I think that it's even more critical to have this occur in the DAC, - such as APL, PS Audio, and (somewhat Chord), are doing..... Instead of relying on external devices, (computer software outside the DAC)

 

Those devices have so tiny bit of processing power compared to what you can do with modern CPU + GPU combination. And it is much better done external to the DAC, so not putting the electrically noisy processing near the sensitive analog parts. On hardware side dCS has been doing that for long time and now Chord too with MScaler. But they are still very resource constrained compared to what I can do with something like Core i9-10900K and GeForce RTX2080Ti.

 

So, it is critical to have this happen outside of the DAC and have DAC be just that, bit-perfect digital to analog converter without any processing. Just converting digital samples from input to analog as well as possible. Nothing else.

 

Now I can run the heavy processing in a different room and then the processed data is sent to the DAC over network.

 

Quote

the DAC takes any signal and converts it to DSD on the fly, - so you might as well use SPDIF 24/192 as that takes care of everything...  or so their owners believe.

 

I just do the same in a computer, in the player application. I can also deal with S/PDIF inputs, or even analog inputs from vinyl and such. And perform digital room correction and such too on the same processing pipeline.

 

[Miska]

1 minute ago, Albrecht said:

I see your point. But one definitely needs a DAC that will accept DSD signal as an input. 

 

Not necessarily.

 

2 minutes ago, Albrecht said:

I guess were I was confused was the difference between DSP and Digital Signal Conversion....???

 

DSP is essential piece of converting your regular source media to analog these days. Conversion process consists of two pieces, the DSP part and the D/A section that converts output of the DSP section to analog. It makes sense to keep these two separate.

 

3 minutes ago, Albrecht said:

I would love to hear a demonstration of what you're doing vs what is going on in a well implemented DAC that does the conversion there.... (every appropriate DAC is well north of $12K).

 

Haha, price is not defining factor here. But you could get started with T+A SDV 3100 HV. It can take directly DSD1024 network input from HQPlayer and convert it to analog through a bit-perfect discrete D/A section. This was also demonstrated at Munich High-End 2019 at the T+A booth.

 

7 minutes ago, Albrecht said:

(if HQPlayer doesn't run on a NAS)

 

NAS are badly under powered and otherwise unsuitable for such tasks. But just I built a pretty nice i9-10900K server from parts for the purpose. Without GPU the parts cost was around 1800 EUR. With a nice RTX2080Ti GPU you would add some 1600 EUR to it. Compared to audio components you are talking about, pretty decently priced, especially given that it has so much more processing power!