DS DAC questions and concerns


#1
Hopefully by the end of this month I'll have my very own DS DAC in my very impatient hands! :-)
By digging around in the manual for my Oppo BDP-105, I discovered that it may be possible to output all audio (including SACD, amazingly enough) in PCM (LPCM) format. This is what is in the Oppo manual on page 19:
Due to bandwidth limitations, high resolution audio formats such as Dolby Digital Plus, Dolby TrueHD, DTS-HD High Resolution and DTS-HD Master Audio cannot be sent through the coaxial or optical digital audio output. A reduced resolution version of the same audio track will be output instead. To listen to high resolution audio formats in their best quality, please use the HDMI connection if you have a receiver that handles HDMI audio (see page 11) or use the multi-channel analog outputs if you do not (see page 18).
Due to copyright restrictions, SACD audio cannot be sent through the coaxial or optical digital audio output. To listen to SACDs, please use the HDMI or analog audio connections.
Due to copyright restrictions and bandwidth limitations, full resolution audio from DVD-Audio discs cannot be sent through the coaxial or optical digital audio output. To listen to DVDAudio in full resolution, please use the HDMI or analog audio connections.
On page 68 it says this:
SACD Output: Allows you to select HDMI the audio output format for SACD playback.
PCM – SACD data is converted into multi-channel, high-resolution PCM data. The converted PCM data is then output through HDMI or the internal DAC (Digital to Analog Converter) for the analog audio output ports. If you use a receiver that supports HDMI v1.1 to listen to SACD, please select this option. You may also want to select this option if you prefer the sound quality of the DSD-to-PCM conversion.
DSD (default) – SACD Direct Stream Digital (DSD) data is output over HDMI without any conversion. For the analog audio outputs, DSD data is converted into an analog signal directly by the internal DAC. If you use a receiver that supports HDMI v1.2a with DSD over HDMI, or you prefer the sound quality of straight DSD to analog, please select this option.
So here’s my question -- and I think I know the answer, alas: Can I connect the Oppo via HDMI cable to the I2S input of the DS DAC? Is it compatible in any way? If this is possible, then the DS DAC would be connected directly to my amp and the Oppo would connect via coax and HDMI, with the volume control handled by the DS DAC. The worst-case scenario would necessitate my purchase of a passive preamp of some sort. I hope I don't have to go that route, even though the well-reviewed Channel Islands VPC-3 I'm considering would not appear to alter the output at all.
Of course, when I test this, I have to listen to all types of discs. I watch classical music DVDs and Blu-rays, as well.
Another concern is my Mac Mini that, because of its (pretty much cast-in-concrete) placement in my room, cannot be connected via USB; it has to be connected via a 25-foot TOSLINK cable to where my audio rack is. That type of connection limits the output to 24/96 for all practical purposes, I guess.
I am, at Paul's suggestion, using BitPerfect with iTunes. It seems to make a difference although I have not critically analyzed it.
Any thoughts?

#2

Hi

Step-1

Replace your toslink cable with the same length USB cable. This will allow greater flexibility and convenience.

You can then compare the two for SQ.

If the Mini cannot be moved because of a TV connection, then a long HDMI cable can ren from the Mini in your audio rig, back to the TV.

An Apple TV would accomplish the same.

This would also feed a computer screen. [HDMI of VGA]

My mini is now in my rig and connects to TV with HDMI and works great. Newer Minis 2010+ can use Airplay.


#3

Just to be explicit the HDMI connectors on PS Audio equipment aren’t electrically compatible with real HDMI. They were chosen for I2S by PS Audio because HDMI cables which have 3 balanced pairs of connections and are widely available.

You wont be able to get SACD’s DSD output with any possible cable combination. You also probably won’t get a hi-rez PCM version of it either.


#4

That’s what I thought, Ted, but I just wanted to hear it officially. So, I guess based on what you wrote, a passive preamp is in my future?


#5
George Moneo said That's what I thought, Ted, but I just wanted to hear it officially. So, I guess based on what you wrote, a passive preamp is in my future?
I hate to say it but that might be the best way if you have SACDs or DVD-As to listen to... I have thousands so I know how it sucks :) On the other hand a good preamp can, in some systems, be better than a direct to amp connection...

#6

Gordon,

Paul and I had an email discussion about USB cables a while back. He told me that a shorter USB cable would be the better option.

I discovered that the long USB Cables I had – in excess of ten feet and not expensive or high-end in the least – were pretty unstable and exhibited significant data drop-outs. However, both Paul and Ted have said that DS DAC is pretty agnostic when it comes to the USB cable. Would buying a higher quality 25-foot USB to connect my Mac Mini to the DS DAC be a solution? Is it worth the investment of a high-end 25-foot USB cable?

I’d hate to spend the money and discover I had the same issue I had before.


#7
George Moneo said Gordon,

Paul and I had an email discussion about USB cables a while back. He told me that a shorter USB cable would be the better option.

I discovered that the long USB Cables I had – in excess of ten feet and not expensive or high-end in the least – were pretty unstable and exhibited significant data drop-outs. However, both Paul and Ted have said that DS DAC is pretty agnostic when it comes to the USB cable. Would buying a higher quality 25-foot USB to connect my Mac Mini to the DS DAC be a solution? Is it worth the investment of a high-end 25-foot USB cable?

I’d hate to spend the money and discover I had the same issue I had before.


I’m using a cheap 15’ USB extension cable in my normal setup, then a 7 port hub, … then to the DAC. My USB drives are out on the same hub as the DS DAC… Personally I like the USB UI experience much better than the bridge UI experience. YMMV

I’ve got a USB 3.0 glass USB cable on order http://www.corning.com/opcomm/OpticalCablesbyCorning/products/USB-3.Optical.aspx (at http://www.amazon.com/gp/product/B00JOJRF6K) It’s long (10 meters) and should sound pretty good.


#8
Ted Smith said
George Moneo said That's what I thought, Ted, but I just wanted to hear it officially. So, I guess based on what you wrote, a passive preamp is in my future?

I hate to say it but that might be the best way if you have SACDs or DVD-As to listen to… I have thousands so I know how it sucks :slight_smile: On the other hand a good preamp can, in some systems, be better than a direct to amp connection…


I have, maybe, thirty SACDs, about a half-dozen Blu-ray Audio discs, and no DVD-As. When compared to the over three thousand CDs I have, it’s not a huge concern, although there are some of those discs that have become a sound reference for me. The Munch Daphnis on RCA, and the complete Wagner Ring on Blu-ray Audio are desert island stuff.

I have the Oppo connected directly to the amp now and it such a HUGE improvement over my venerable, old Classe Model 30 preamp that I recently sold, that I’m loath to place something in between the source and amp again.

The proof will be in the pudding, I guess, once I get that DS DAC…


#9

Another option would be for me to buy a PerfectWave Transport for my CDs and keep the Oppo for everything else.

I know that solution would make Paul happy. The wife? Not so much… :-)

BTW, the PWT connects to the DS DAC via the I2S connection and uses a standard HDMI cable, yes?


#10
George Moneo said Another option would be for me to buy a PerfectWave Transport for my CDs and keep the Oppo for everything else.

I know that solution would make Paul happy. The wife? Not so much… :-)

BTW, the PWT connects to the DS DAC via the I2S connection and uses a standard HDMI cable, yes?


Yep, you can use an HDMI cable, a AES/EBU balanced cable, a S/PDIF coax or TOSLink…

#11
Ted Smith said
George Moneo said Another option would be for me to buy a PerfectWave Transport for my CDs and keep the Oppo for everything else.

I know that solution would make Paul happy. The wife? Not so much… :-)

BTW, the PWT connects to the DS DAC via the I2S connection and uses a standard HDMI cable, yes?

Yep, you can use an HDMI cable, a AES/EBU balanced cable, a S/PDIF coax or TOSLink…


Isn’t a flat HDMI better, because you have more control over the lenght of the conductors, and as we know identical length on wires (and preferably internal/external short lenght) is critical for I2s?

#12
Frode said
Ted Smith said
George Moneo said Another option would be for me to buy a PerfectWave Transport for my CDs and keep the Oppo for everything else.

I know that solution would make Paul happy. The wife? Not so much… :-)

BTW, the PWT connects to the DS DAC via the I2S connection and uses a standard HDMI cable, yes?

Yep, you can use an HDMI cable, a AES/EBU balanced cable, a S/PDIF coax or TOSLink…

Isn’t a flat HDMI better, because you have more control over the lenght of the conductors, and as we know identical length on wires (and preferably internal/external short lenght) is critical for I2s?


The three differential pairs in the HDMI cables are speced for differential connections, that one reason PS Audio uses them for this purpose. If they were slightly off in length one pair to another that wouldn’t matter at all. If the two wires in the clock pair are different lengths it would add a bit of jitter. But one of the strengths of the DS is jitter insensitivity and I’m pretty sure that almost one could tell an excellent HDMI cable from a average one in a double blind test on the DS. I use a $9 Radio Shack HDMI cable :)

#13
Ted Smith said I use a $9 Radio Shack HDMI cable :)
Say it isn't so! cant-believe-my-eyes-smiley-emoticon_gif

Do you at least dip them in fairy dust prior to use?


#14
Ted Smith said I use a $9 Radio Shack HDMI cable :)
Sir, you are an iconoclast. And that is a good thing.

I remembered that I have a 25-foot USB cable I purchased for some computer hardware I never ended up using. I’ll try that one when I get the DS DAC and report back.


#15

Ted,

What about USB cables with active circuitry, like these:

http://www.newegg.com/Product/Product.aspx?Item=N82E16812120627

http://www.monoprice.com/Product?c_id=103&cp_id=10303&cs_id=1030301&p_id=7531&seq=1&format=2

The price is right for experimenting. The Transparent Audio USB (A to B) 30-footer costs $650!

(I’ve misplaced the long USB cable I thought I had, unfortunately. And I correct myself that it was a 15-foot cable, not 25.)


#16
George Moneo said Ted,

What about USB cables with active circuitry, like these:

http://www.newegg.com/Product/Product.aspx?Item=N82E16812120627

http://www.monoprice.com/Product?c_id=103&cp_id=10303&cs_id=1030301&p_id=7531&seq=1&format=2

The price is right for experimenting. The Transparent Audio USB (A to B) 30-footer costs $650!

(I’ve misplaced long USB cable I thought I had, unfortunately.)


Don’t even think about a long USB cable that doesn’t have active circuitry. Also you probably want an powered hub on the end of the long cable. Powered hub’s power supplies matter, but that’s better than having the power that comes down the cables being affected by the signal all of the way along the cable. My 15’ active USB cable is pretty generic: I don’t remember if I got it from radio shack or Fry’s but I get excellent sound out of it (I use it for every demo I do.)

#17

Ted, you are going to single-handedly kill the specialty cable market. 41_gif


#18
Elk said Ted, you are going to single-handedly kill the specialty cable market. 41_gif
I'll have to do better on the power supply side next time :) There's also a balance between using a transformer for filtering and making it insensitive to interconnect cables ... but much to my surprise transformers are a pretty good thing :)

#19

I have long felt good, quality engineering renders many audiophile tweaks irrelevant.


#20

Ted, I’ll be receiving the passive preamp and a 33-foot active USB cable (per your recommendation) tomorrow.

All I need now is the DS DAC… :-)