PS Audio DirectStream DAC - The Review That Almost Was

BlueFox

The hard part about FPGAs is the programing to get the desired funtionality. It is a lot easier to buy off the shelf DAC ASICs than to write the software that accomplishes the same thing. The benefit of a FPGA is, assuming the rest of the hardware is up to it, is you can tweak the software to make the sound better and better. You can't do that with ASICs. Of course, with FPGAs at some point you will have squeezed every bit of performance out of it. Hopefully, the PSA DS still has a ways to go.

Moose68Bash

Today, I decided to listen to the Guarneri Quartet's recordings of Mozart's String Quartets Nos. 14 and 15. These are remastered recordings from the early 1970s. They are very good, not outstanding, in quality, but I have always appreciated the music. I wanted to see what the DSD would do with them.

Would the shortcomings of the recordings become so pronounced that I would no longer enjoy the music, or would the DsD "pull out" of the recordings aspects of the music and performances that would enhance my enjoyment? Or would it be some of each?

In sum, the DSD made the experience far better than I had ever known before. The stereo image was of four musicians arrayed on the soundstage making music that had so many characteristics of a live performance that I was extremely pleased.

As the lead in the music passed among the first violin, second violin, cello and viola, transitions were clear and distinct in sound, and individual instruments were palpably located on the soundstage.

In the minuet of Quartet No. 16, for example, there is a beautiful section in which one instrument after another takes the lead part, while others play accompanying pizzicato passages.

As I sat with eyes closed listening, I experienced both the separation and the movement of the parts as individuals in the quartet performed them. While the timbre of instruments still reflected some shortcomings of the recording technology, the DSD effectively pulled out and rendered an image of a quartet playing the music better than I had ever perceived it before.

DarqueKnight

BlueFox wrote: »

I believe they also use FPGAs for their digital gear.

I asked dCS if they were the first to incorporate FPGAs in their DACs:

"We began using FPGAs in our home/consumer products beginning in 1996 when we introduced our first consumer product, the Elgar DAC; that said, it’s quite likely we were the first, but I’m not certain of that as fact.

More importantly, what I can tell you is the FPGA has been the basis for all our designs since then, and over the nearly-twenty years we’ve made consumer products all dCS models introduced since the Elgar have offered numerous software upgrades throughout their lifespan afforded by this design choice. The most current series, Vivaldi, actually uses up to five of those wonderful devices in a single chassis to allow us to modify and improve the unit’s performance to an even greater degree than ever before."

Moose68Bash

DarqueKnight,

Great information.

It would be interesting to know how much the chips cost when dCS first started using them in 1996 compared with what they cost today.

I suspect the price has gone down dramatically, and I wonder to what extent it has been reflected in dCS pricing of their products. I don't know their pricing that well, but it seems that they have used the FPGAs as a way to keep customers happy after they have paid a fairly steep price, rather than to use declining cost of components like the FPGA chips as an opportunity for price reductions.

The use of FPGAs in lower price products will likely drive prices down and allow other manufacturers to compete better on SQ as well.

DarqueKnight

Moose68Bash wrote: »

It would be interesting to know how much the chips cost when dCS first started using them in 1996 compared with what they cost today.

I suspect the price has gone down dramatically, and I wonder to what extent it has been reflected in dCS pricing of their products. I don't know their pricing that well, but it seems that they have used the FPGAs as a way to keep customers happy after they have paid a fairly steep price, rather than to use declining cost of components like the FPGA chips as an opportunity for price reductions.

The use of FPGAs in lower price products will likely drive prices down and allow other manufacturers to compete better on SQ as well.

For a lower price products (sub $2000) I don't know if using an FPGA would be an economically viable option over using an off the shelf chip. It might be, but I don't know enough about FPGAs and how widely they are used in audio components.

I'm skeptical that high end computer audio will see significant price reductions because the "computer" parts are a relatively small part of a computer audio component.

dCS's products use a lot of other expensive components that typically do not drastically go down in price over time like computer chips, such as:

1. Milled aluminum cases (yes they affect the sound).
2. Custom, proprietary circuit boards.
3. Premium electrical components.
4. Low noise analog output stages.

There are also differences in FPGA chip quality and performance. There are two versions of the dCS Debussy DAC, Ver.2 has different FPGAs and software than Ver.1. There was a $1500 difference in price when Ver.2 was rolled out.

If you were to put the DS DAC's software in a higher performance, higher quality FPGA chip, then replace all the circuit components and wiring with premium grade parts, then put all the components on premium quality mil-spec circuit boards, then put all that in a heavy, anti-resonant, electrical noise resistant milled aluminum chassis, the cost would likely double, but the performance might also double or more.

Think of what we do with SDA modifications and the AI-1 interface. We don't change the basic operation of the speaker and AI-1 interface, we just replace lower quality, lower performance parts with higher quality, higher performance parts. The result is a speaker and non common ground interface that is still true to the original design intent, but is worlds better in terms of performance.

Moose68Bash

DarqueKnight,

As always, your analysis is very sensible. DACs and computers have a lot in common, but they are also quite different in many important respects.

One of these days I hope I'll get my hands on a dCS DAC -- to audition, if nothing else. I'd love to hear a really top-of-the-line DAC in my system.

I really appreciate your thoughtfulness in discussing all things audio.

What are you going to do when you get really serious about this hobby?

DarqueKnight

Moose68Bash wrote: »

What are you going to do when you get really serious about this hobby?

I try not to think about that. It's a scary thought.

DarqueKnight

Follow up:

DarqueKnight wrote: »

I asked dCS if they were the first to incorporate FPGAs in their DACs:

"We began using FPGAs in our home/consumer products beginning in 1996 when we introduced our first consumer product, the Elgar DAC; that said, it’s quite likely we were the first, but I’m not certain of that as fact.

More importantly, what I can tell you is the FPGA has been the basis for all our designs since then, and over the nearly-twenty years we’ve made consumer products all dCS models introduced since the Elgar have offered numerous software upgrades throughout their lifespan afforded by this design choice. The most current series, Vivaldi, actually uses up to five of those wonderful devices in a single chassis to allow us to modify and improve the unit’s performance to an even greater degree than ever before."

My inquiry was forwarded to dCS's engineering department and I received this reply:

"Actually, I don’t know the answer to that. As far as I know, our first use of FPGAs was the dCS 950 24/48 DAC in 1993. I recall being approached by AT&T FPGA application engineers around 1990 (before I joined dCS).

dCS has a long string of world’s first and inventions:

24 bit
24/96
Dual AES
Upsampling
24/192
DSD
24/384
DoP
and many more."

BlueFox

DK, my PSA DS DAC will arrive Thursday. Do you know if I can hook up both the USB and AES between the BDP-1 and the DAC so that I can use the remote to switch between the two. If that works then it should be easy to tell if one is better than the other.

DarqueKnight

Yes you can.

The USB connection between the BDP-1 and the DS DAC drops sometimes and you will need to restart the DS DAC to reestablish the connection. I did not have this problem with the AES and coax connections.

DarqueKnight

DSkip wrote: »

The issue is on the computer side.

Yes. The "computer" (Bryston BDP-1) does not have a proper driver for the DS DAC.

I had USB issues with both of the DACs tried to date: the DS DAC and the Cary DMC-600SE.

I didn't have dropped connection issues with the Cary, but I would get audio dropouts at the beginnings of songs and sometimes dropouts in the middle of songs. This was due to a buffering issue with the BDP-1.

I initially experienced the same dropouts using my laptop computer and JRiver Media Center, but changing JRiver's settings to increase the gap between songs to 1 second and increasing the buffer size resolved the problem.

BlueFox

Well, if USB turns out to be a pain in the buttocks then AES it is. I might just take off Friday so I can stay up all night Thursday evaluating the DS.

DarqueKnight

BlueFox wrote: »

Well, if USB turns out to be a pain in the buttocks then AES it is.

I recall you saying you had no interest in DSD, but for those who do, the BDP-1 only outputs DSD over USB. That sucks because the BDP-1's USB output is the lowest performing of the three.

BlueFox wrote: »

I might just take off Friday so I can stay up all night Thursday evaluating the DS.

Yeah, that's how it goes in the rabbit hole.

BlueFox

Yes, at this point DSD is not on my radar. However, I thought I read somewhere that USB on the DS performed the best. I will find out, and maybe have a Shunyata Venom 1.5 meter USB up for sale.

Moose68Bash

BlueFox wrote: »

Yes, at this point DSD is not on my radar. However, I thought I read somewhere that USB on the DS performed the best. I will find out, and maybe have a Shunyata Venom 1.5 meter USB up for sale.

I don't use USB input to my DSD, but I do use ethernet through the bridge, coax (initially for the Cambridge Audio iD100 iPod dock), optical (for audio from DVDs), I2S (for the PS Audio transport), and AES (now for the Cambridge Audio iD100 iPod dock).

I have had only one problem with these inputs -- one time I had to reset the bridge.

My ranking of the SQ would be (from best to worst):

1. Ethernet from the NAS
2. I2S from the PWT
3. AES from the iPod dock
4. Coax from the iPod dock
5. Optical -- which I also briefly tested with the iPod dock

I cannot discern much difference between 1 & 2. My wife prefers input from the PWT via I2S.

I realize this list is not comparing apples to apples, perhaps, with the exception of the three comparisons of the SQ from the iPod dock. The CA dock claims to take bit-perfect output, and I have all my music in aiff files. SQ has been better than I expected.

I also have a Wadia 171 iPod dock that I use in my second system with a PS Audio Perfectwave MKII. It is connected with the Wadia stock coax cable. I think it produces better SQ than the CA dock, but I keep it in my second system because that is where I most often use my iPod (about 1-1.5 hours per day, five days per week during physical therapy).

BlueFox

I love my Wadia 171 and iPod. That was my first music server. Used with a Benchmark DAC1, it makes a great headphone/work system.

Moose68Bash

BlueFox wrote: »

I love my Wadia 171 and iPod. That was my first music server. Used with a Benchmark DAC1, it makes a great headphone/work system.

I wanted to get a second Wadia 171, but they went out of production shortly after I purchased the first one. It was a good product.

Moose68Bash

Nobody has commented (as I recall) about the SQ of the PS Audio Directstream DAC when it is used as a preamp. PS Audio recommends connecting the DSD directly to an amp.

I tried this configuration -- connecting the DSD directly to my Perreaux monoblocks.

Neither my wife nor I considered this configuration acceptable, let alone superior to using the Perreaux SM6P MKII pre in our system. I have not had it in my system for a few months, now, so I won't attempt detailed criticism.

I will say, however, that the rendition of the music sounded very veiled or muted v. the rendition with the pre. The difference was so pronounced and immediate that I did use the DSD as a pre for even 24 hours -- clock time, not listening time.

BlueFox

Mine arrived today, and it did not include an SSD card, so I am using 1.2.1. It is running now, and everything (amps and DAC) is warming up. It does not sound bad right out of the box, but I will get more into it later tonight.

Any idea what size SSD card I should order, or does it not matter. The manual gives no spec for it.

Moose68Bash

≈

BlueFox wrote: »

Mine arrived today, and it did not include an SSD card, so I am using 1.2.1. It is running now, and everything (amps and DAC) is warming up. It does not sound bad right out of the box, but I will get more into it later tonight.

Any idea what size SSD card I should order, or does it not matter. The manual gives no spec for it.

You can use any 2G SSD card -- NOT larger.

I used one from my camera after wiping it. No problems.

The PS Audio web site also give you instructions for the download and installation.

BlueFox

Great. I just ordered a 4G card.

Moose68Bash

BlueFox wrote: »

Great. I just ordered a 4G card.

According to the PS Audio web site, any card larger the 2G will not work.

You'll need a 2G card.

BlueFox

That kind of bugs me. The manual mentions nothing of this, and on the PS Audio forum the responses are all over, with some saying a 2G card is getting difficult to find.

DarqueKnight

BlueFox wrote: »

Any idea what size SSD card I should order, or does it not matter. The manual gives no spec for it.

Moose68Bash wrote: »

I used one from my camera after wiping it. No problems.

BlueFox wrote: »

That kind of bugs me. The manual mentions nothing of this, and on the PS Audio forum the responses are all over, with some saying a 2G card is getting difficult to find.

I saw Paul's comment on the PSA forum saying that an SD card is not included with the DS DAC. I was very surprised at this because firmware updating is one of the key features of the DAC. All three of my PSA Powerplants came with 2 GB SD cards. I don't recall if my DS DAC came with an SD card, since I didn't check due to there being no firmware updates at the time. I have seen others mention that their DS DAC came with an SD Card.

I do recall that the Powerplants are limited to 2GB cards. I don't know if that restriction holds for the DS DAC. As you noted, the manual provides no advisement.

BlueFox

Paul also said if your order the DS with the Bridge option then it comes with an SSD card.

Also, while I hate to admit this, this Vanilla forum is better than the PS Audio forum.

Moose68Bash

Go to the URL below, and play the video.

The first statement in the tutorial is that "you will need a 2G SD card."

http://www.psaudio.com/support/downloads/

I also read that a 2G SD card was specified, but I can't find the link. I followed the instruction that I read. Wish I could find them, but I can't.

Here it is:

"You will need a standard SD memory card to load the files onto. You can only use a standard SD card that does not exceed 2gB in size. Ultra, Ultra II SDHC SD cards cannot be read in DirectStream. Make sure the SD card is a standard version."

The link is:

http://www.psaudio.com/ps_how/upgrade-directstream-operating-system/

BlueFox

One shouldn't have to search all over a web-site to find something that should be in the manual. Anyway, I just ordered a 2G and will return the 4G.

Moose68Bash

BlueFox wrote: »

One shouldn't have to search all over a web-site to find something that should be in the manual. Anyway, I just ordered a 2G and will return the 4G.

I couldn't agree with you more.

I've also sent at least two emails to tech support at PS Audio to which I have received no acknowledgement, let alone replies.

Not very customer oriented in general, except that from reading various threads on the forum I sense that there are some "privileged characters."

DarqueKnight

Moose68Bash wrote: »

I've also sent at least two emails to tech support at PS Audio to which I have received no acknowledgement, let alone replies.

Not very customer oriented in general, except that from reading various threads on the forum I sense that there are some "privileged characters."

Whenever I contacted tech support through the website, it took a few days to receive a response. However, whenever I contacted a specific person by email, I received a same day response, even when I sent emails in the evenings. I learned early on that if I had a problem that required immediate attention, I should not use the web interface to contact PSA's tech support.

I agree that the issue with no SD card for the DS DAC and no recommendation for the required 2 GB card in the manual are blunders, but this is not typical of PSA's customer support.

BlueFox

I couldn't get the customer support page to accept my question whether an SSD card should be included or not, so I sent it to sales. An hour later I got a reply saying it is not included.