Article: PS Audio DirectStream DAC Review

[ted_b]

NO! The DS is a fine fine USB dac...what do you mean "Bad DAC" when I conclude:

"As a dual format USB DAC it is very good and recommended on all $5K+ budget's short list". ?

 

My love of the I2S connection is simply "in my system, with my stuff". Ben-M nails that point. As many know I love the Chord Hugo, too, and as a USB DAC it has higher value than the DS (simply cuz it is 40% of the cost for 95% of the performance of PCM and maybe 85% of the performance of DSD). Those extra few percentages are expensive......I'm tell us all something we all know.

 

In my system the USB (whether via Jplay/JRiver/Caps and tweeked WS2012 AO...or...Auralic Aries via same isolation and power tweaks) is NOT equal to the I2S. Is it the Sonore? Is it the I2S? Dunno...I think it is a little of everything, and I will try to quantify it further as I work on various combinations down the road. I am most surprised, however, that what would appear to be a poor choice for music server (Intel Atom 2700 x86-64 cpu with fans, 2Gb stock RAM and 8 spinning discs.....aka Synology DS1513+/DX513 NAS) produces a beautifully noiseless stream of wonderful music. Go figure. It's Media Server app does native DSD with I2S (no DoP needed) and does auto-synching when new music is added. For now I like it better than Minimserver. I am likely not looking deep enough, but at the moment I don't care.

[RSB]

Distinctive - Thanks for the confirmation that the DS is compatible with my upstream gear (an OR5).

 

Ksalno - Yes, the OR5 is getting long in the tooth, and doesn't do DSD. I have been on the sidelines with DSD because of that, and want to experience the new technology. I'm guessing the CAers that are into DSD are contributing to this thread, so I'm hoping to learn here.

 

My prior impression is that connecting via I2S to my DAC2 gives a more direct path to the DAC chip, and bypasses the other input circuitry on the DAC and which themselves subsequently connect into the I2S. My thinking is that the higher quality converter gets the DAC2 DSDse to hit above it's price class. So in my limited thinking, I am not at all surprised by your experience as it mirrors mine... My great respect for the I2S connection kindles in me a desire to hear the DS connected by it, thinking it will widely surpass my current rig and offer DSD, too.

 

Now let me offer a lot of caveats, here. I am no expert, and these are just my amateur impressions, and of course, don't necessarily relate to the DS at all, which I have not heard, and is in another league altogether. I fully expect that what you have experienced with the DS will have another explanation entirely, given its already wide ranging experience in the market and rave reviews. However, I thought it would be interesting to share my experience as grist to stimulate discussion about the I2S connection. But your experience DOES suggest to me that the combination that you heard reviewed is very top tier...

 

Thanks, and Merry Christmas,

 

Randy

[alcarp]

It's very interesting that neither Paul McGowan nor Ted Smith use the I2S connection - they favor the USB.

 

Have most of us missed something here?

[hardline]

Ted_b - thanks for a great informative review. Would be great to have a multichannel version of this DAC.

[highstream]

alcarp, I've had the same question, although I don't know which systems are involved.

 

I don't have the setup for I2S, so I was using the DS with a TotalDac1 USB cable/filter, JCat USB card and Core Audio Kora LPS in a Win 8.1 i7 desktop computer. It was pretty good, sometimes really good on PCM files and recordings. Then a week ago I decided to drop in the Bridge from a PWD I was selling, just to see if it sounded (and acted) better with the DS than it had with the PWD. I ran a Blue Jeans cat7 ethernet cable from a router that sits between a cable modem and my computer, and reloaded the Wavestream driver, setting up UPnP in foobar (also JPlay using Xtream). All I can say is that things blossomed in just about every dimension one can think of, most significantly a sense of the music coming alive, and w/o bite, unless it was there on the recording. Going back and forth with the TotalDac cable reaffirmed that. Today, I received an Audiostream Vodka ethernet cable to audition, and even barely burned it's brought another level of clarity, staging and sense of presence. I'll also be trying a Meicord from Germany and, if I can handle it, maybe one or two others (JCat, Audioquest Diamond). All of which makes me wonder: here the discussion has turned around I2S, but on the PS Audio forums there seem to be a number of people who find the ethernet route preferable, at least to USB. But then Ted B's informative review didn't really say much specifically about his experience with that input.

[ajay556]

NO! The DS is a fine fine USB dac...what do you mean "Bad DAC" when I conclude:

"As a dual format USB DAC it is very good and recommended on all $5K+ budget's short list". ?

 

My love of the I2S connection is simply "in my system, with my stuff". Ben-M nails that point. As many know I love the Chord Hugo, too, and as a USB DAC it has higher value than the DS (simply cuz it is 40% of the cost for 95% of the performance of PCM and maybe 85% of the performance of DSD). Those extra few percentages are expensive......I'm tell us all something we all know.

 

]

 

Hugo 95% of PS audio in PCM format. Glad to hear that ....i own a hugo dac and i am auditioning the PS audio DS. I feel the PS audio is sweeter and more coherent. The hugo definitely has more bass but less sweeter. I have not had lot of time with the ps audio was a surprised to read 95%....How are you connecting the hugo? I am using the PS audio transport.

 

I still need more time but can keep only one...hugo or PS audio...yes hugo is much cheaper...

[ted_b]

Thanks for the initial feedback on the Bridge. I have NO way to experience the DS ethernet connection, because I do not own nor have a demo of the Bridge (I know of no other unit that connects ethernet to the DS).

 

I connect the Hugo via USB (TotalDAC or JCAT, via JCAT card, etc). They are two very different presentations. If you can't decide, then don't fret; the Hugo is a huge value.

[perolator]

Thank you for your honest and detailed review, Ted. I am a huge DSD fan and was delighted with your thorough review. Personally I think FPGA's are the way to go with DACs (i.e Chord Electronics). All will depend on the firmware, It'll guarantee an easy upgrade path.

[Ted Smith]

It's very interesting that neither Paul McGowan nor Ted Smith use the I2S connection - they favor the USB.

 

Have most of us missed something here?

 

I don't think so. Everyone needs to test these things in their own systems. I have other paths from my PC to the DirectStream besides USB, but USB can do double rate DSD and uses fewer cables/extra boxes when I go on the road.

 

In the DirectStream there's nothing magic or more direct about I2S inputs than other inputs, in fact the TOSLink input is the simplest - a wire from the TOSLink connector to the FPGA. Internally the I2S inputs form the HDMI connectors, USB and the bridge all talk to the FPGA with I2S. Since the DirectStream doesn't recover clocks from any inputs jitter differences between the inputs don't matter. The real differences are things like groundloops, EMI, etc. the I2S cable often has better grounding that other cables so it has an advantage over other cables. TOSLink has the advantage of galvanic isolation. USB has the problematic VBUS connector which is another way to receive noise and pass it to the DAC and hence is at a bit of disadvantage. Using Ethernet can also introduce groundloops and a lot of noise, so comparing the bridge to other inputs is even more system specific.

 

-Ted

[highstream]

Thanks for clarification, Ted. I've noticed that since switching to the Audioquest ethernet cable, my Quad powered speakers are humming audibly again. I use TOSlink in my 2.0 TV setup, normally with a PWD II, but when I tried the DS there it sounded awfully good. However, I find the cost of another DS hard to justify for watching TV shows, video and PCM music files and DVDs in a not very sound optimized living room.

[ajay556]

How does one play DSD? Just use macbook air and good USB cable should suffice? Or is that not a good test for DSD?

[ted_b]

DSD is now available via dozens of different output player/hardware/OS setups. DSD is sent natively or via DoP. In the Directstrem specifically, DSD is bitstreamed natively via I2S; I described in my own Rendu setup, with either Minimserver (no streamer config options) or Synology Media Server. You can send it via DoP in many inputs (USB via Linux, Windows or Mac; SPDIF, AES/EBU or I2S). If going DoP via Minimserver then make sure you have DoPwav configs set up in the stream.transcode config field.

[Distinctive]

DSD is sent natively or via DoP. In the Directstrem specifically, DSD is bitstreamed natively via I2S

This is true, however internally in the DS the native DSD stream fed to the I2s input is converted to DoP along with the remaining inputs. This, however will not result in a loss in sound quality.

[ted_b]

Ted Smith says "....the DS can consume single rate DSD via DoP on any input, double rate DSD via DoP on all inputs except TOSLink and the bridge, and native single rate and double rate dsd (raw dsd) over the I2S inputs. We MAY in a future release update the USB drivers to support raw DSD".

 

So, Distinctive, why would they care about raw anything (such as spending time to later release a raw USB driver) if it's all DoP at the end of the line anyway? Net/net, I'm confused by your answer.

[Distinctive]

Ted Smith says "....the DS can consume single rate DSD via DoP on any input, double rate DSD via DoP on all inputs except TOSLink and the bridge, and native single rate and double rate dsd (raw dsd) over the I2S inputs. We MAY in a future release update the USB drivers to support raw DSD".

 

So, Distinctive, why would they care about raw anything (such as spending time to later release a raw USB driver) if it's all DoP at the end of the line anyway? Net/net, I'm confused by your answer.

@ted_b;

There are several threads touching on this subject over at PSA forum.

Here is one: Playing double-rate DSD on the DS | DirectStream DAC | Forums | PS Audio

Ted Smith has explained this in detail, however to not risk explaining the wrong things I reckon Ted himself may chime in on the matter. The main issue is to avoid several conversions prior to processing the audio signal in the FPGA.

[ted_b]

Distinctive, Nice catch. So now even more confused.

 

Ted-Smith, so is it more proper, if given the options, to stay DoP on, say, Signature Rendu I2S-Minimserver, since you are using DoP to traverse the 24 bit paths out to deep space? Or is raw/native DSD (via I2S) the better way cuz then you don't have certain work to do?? Are you looking to go raw USB someday simply to appease marketing? Thx

Ted-B

[Distinctive]

Distinctive, Nice catch. So now even more confused.

 

Ted-Smith, so is it more proper, if given the options, to stay DoP on, say, Signature Rendu I2S-Minimserver, since you are using DoP to traverse the 24 bit paths out to deep space? Or is raw/native DSD (via I2S) the better way cuz then you don't have certain work to do?? Are you looking to go raw USB someday simply to appease marketing? Thx

Ted-B

I hope this doesn't mean that that you suddenly think the DS I2s is not superior after all

To me Ted's answer seemed perfectly reasonable when explained.

[ted_b]

? The setup I have is superior to anything else I tried (I didn't try to force DoP cuz at the time why would I); nothing technical will change how I feel that particular setup sounds. The comments here are simply to help me find out why? And what pieces are important variables. If DoP vs raw makes no freaking difference, it's good to know. If DoP is better than raw, then that is also good to know. Example: For some DACs the ASIO (Windows) raw non-DoP DSD stream can elicit better feedback from some listeners. This is often explained as either having more cpu overhead with DoP (a rather weak proposition but in the category of "everything matters" maybe it's enough to affect sound) or that the mfg'ers ASIO driver is simply a better design (whatever that means).

 

What doesn't seem reasonable (or a better term would be "explainable") is why would a company prepare/announce a possible new USB driver direction (ASIO and/or raw) if it is contrary (or irrelevant) to the correct signal path (all DoP). So unlike you, I am still scratching my head.

[Ted Smith]

Howdy

 

In a player it's not obvious which method will have better sound quality: wrapping DSD in DoP or using a higher sample rate. It's easy to imagine either one causing sound quality degradation depending on the rest of the system.

 

My hypothesis is that certain DAC chips get a cleaner (lower jitter) clock from the 2.8MHz input of raw DSD compared to the 176.4kHz clock of DoP. There is marketing pressure to support raw DSD because some don't understand that DoP is lossless and cheap and/or some believe that raw DSD is more "pure" than DoP. When it's convenient we will support raw DSD over USB just for the marketing checklist, not for any particular technical reason.

 

In the FPGA implementing something to get raw DSD thru the same FIFO as PCM or having separate PCM and DSD FIFOs is a more code/processing than the minuscule work of wrapping raw DSD into DoP and using the extant DoP/PCM path. In general any extra code is a chance for bugs, takes more work to test and often decreases sound quality.

 

-Ted

[ted_b]

Ted, thanks. So raw or native DSD is, if anything, a miniscule bit of MORE work (assuming the DoP coming from sources needs not be re-wrapped)?

[ALRAINBOW]

Ted -b. I have a question did you use a winserver and AO. ???

As I have tested th DS with all of its inputs and usb is just better. Yes it's marginal but it's there. I have a sample of the B2 as well i do still feel usb edges it out.

Regarding the Hugo and DS I do see your point and agree to a point there. Although the hugo is cheaper the ds is more than enough better to warrant the additional cost.

To me as good as the hugo sounds it is a gimmick device where the DS is a real hi end audio device.

After all who would use a Hugo in a home system if not tempory till,your main dac is purchased.

Lastly what did you prefer was better with the DS , pcm or DSd. And as I am not of the camp that so called DSd pure is better than dop. If I cannot hear it than its just not true.

 

For me I think for the two dacs you mentioned there strong points are pcm not dsd

any thoughts.

And I am glad your review is finally out . Nice read .

al

[Ted Smith]

Ted, thanks. So raw or native DSD is, if anything, a miniscule bit of MORE work (assuming the DoP coming from sources needs not be re-wrapped)?

Yep, to use the PCM FIFO in the FPGA the DSD needs to be packed into 24 (or 16) bit words anyway so the theoretically "purer" path is polluted... To be "clean" and have a separate DSD FIFO adds a lot of muxing/ demuxing and more memory usage...

[barrows]

ALRAINBOW: you have listened to the DS via a Sonore Signature Rendu and I2S? Remember, an I2S feed is likely to be more sensitive to the source than USB... Ted's results via I2S were specifically with the Sonore Signature Rendu, which is a no compromise Renderer designed to produce the absolute best I2S and SPDIF feed possible. I think it is important to realize that the source quality is an issue when determining which input of the DS is "best". To declare USB as best as you have is only valid if you have exhausted all possible sources for other inputs.

[ted_b]

Al, as I've already posted the USB via my dual pc AO'd setup is very very good, but not the Sig Rendu at I2S for me. Your preference for USB is yours. Also, I thought I made it very clear that I feel that the DS does PCM slightly better than it does DSD. I said it here:

"This DAC is a difficult one to categorize. It is hyper-DSD internally, yet plays back PCM even better than it does DSD."

 

As far as Hugo being a gimmick device, I gotta stop you there. Seriously? I think the Hugo is one of three or four reference-level DACs I've experienced in the past several years, and deserves a place at anyone's home rig (connector hurdles notwithstanding). Is the DS better? Yeah, but not necessarily through all sources, and not anywhere near available at $2300.

[alcarp]

I found the Chord to have a very different sound signature to the Directstream, anyway.

 

More impact and slam but not as smooth and refined as the DS. Its a matter of personal preference as to which is better.

 

Ted Smith's explanation seems to point to the Rendu (I2S) as being a potentially superior source as far as EMI, RFI etc is concerned.