R2R DACs vs. chip DACs vs. FPGA DACs

For the sake of research I just found 40 PWDs for sale, most of them under half of the original price… Wonder why that is… Anyone…?

Thank you, Ted.

A wonderful summary.

I owned the PWD, thought it was awesome. Then, I sent it to PSA for them to install the DSD upgrade kit. Never looked back. The DSD and my Carey SLP-05 are the heart(s) of my system. BTW, I bought the Cary as a NOS piece for less than half the list price. Nature of the audiophile market.

I bought a used PWD Mk. 2 a couple of years ago and then bought the DSD upgrade kit and installed myself. I love that PS Audio has all these great options of getting into a component for less and then upgrade as funds allow. The DSD is definitely the heart of my digital front end. Really sounds fantastic and got better when I loaded the Window firmware.

1 Like

I should also have said that listening is very important, but not to tune things. Instead it’s the most efficient way of finding the presence of a bug. Sometimes it also narrows down pretty well where the bug is.

PS Audio spends a lot of time listening. They are sorting out the versions of a potential DS release which have too much noise (tho often the effects of that noise shows up as distortions, emphasis of some frequencies or deemphasis, not simply, say, as a hiss or crackle…) Their feedback (and the feedback from the people here on the forum) inform where to look for places to improve the DS’s code. (And future products.) At times I have to stare at the wall for a while to figure out what bug or deficiency would cause the reported prolems in the sound quality.


There are people here with amazing ears who have heard thing I doubt I would ever notice.

Thanks Ted for the thoughtful and thorough explanation. Very insightful! I do wonder why blind listening tests seem so taboo in audiophile design? We are but feeble human beings who are easily swayed by the power of suggestion. Given the very scientific and mathematical approach to your programming, it seems an equally scientific and psychologically accurate approach to listening tests would be not only welcomed, but embraced as the norm.

I’m equally intrigued by the notion that mathematically achieving lower noise always translates into better sound quality. Has this been proven in a scientific way? Aren’t vinyl and tubes quite noisy by nature?

What happens at the end of the rainbow where a pot of music has absolutely no noise whatsoever?

It’s a curious mix as music itself is very unscientific, as most art leans heavily on the unscientific part of our brains.

When I started this project I was not looking forward to “voicing.” Would I have to pick my “signature sound”, etc.?

But when the big prototype was done, it sounded right. Everytime I make a new release more mathematically correct most people like it better. My blind test, if you will, was not listening at all to some releases and still accurately describing the changes in sound.

FWIW, I did a bunch of double blind tests as I was building my system and participated in multiple double blind tests at the local audio club (tho we did way more single blind tests.) On one such night of tests we were trying all manner of CD tweaks, green marker, beveling the edge, zapping with a static gun, you name it. There was an obvious difference on all but one or two treatments to most of the participants. I had a little tinnitus that night so I voted based on whether my tinnitus got louder or more quiet. I noticed I was voting along with the vinyl heads. The CD heads were mostly enjoying the opposite choices.

That helped me learn to trust my ears about jitter. That’s served me well over time.

After a year or so of having my computer run blind blind tests on me (which I think qualifies as double blind testing :slight_smile: ) and after running single and double blind tests on my wife and daughter I just stopped bothering. They took a lot of time and never contradicted my initial impressions. I do know when I don’t hear a significant difference (i.e. when I’d probably get a different answer with repeated tests.) I don’t regret any of my equipment choices based on non-blind tests.

Why would it not be immediately plausible that lowering noise is good? Every time I had a mod done which lowered noise the ambiance of the recording venue got clearer. After a while the recording venue, processed reverb, my home’s coloring of the sound and the media’s noise contribution all were obviously distinct. Without a low noise system some or all get muddled together.
Lowering noise brings out the venue reverb, that’s not an artifact, it clearly helps to have less noise interfering with the recorded sound.

Everything has noise, even a simple resistor (no matter what it’s made of.) What you are often paying for when you get a better amp, better preamp, etc. is a design that uses topologies which handle noise better. Putting two devices in parallel will lower the non correlated noise by 3dB. Clearly this is impractical taken to the limit. The biggest difference between the DS and the DS Jr is that the Jr has one digital switch per channel and the DS has four per channel. That gives the DS a 6dB SNR headstart. The digital switches draw a lot of current so the DS needs significantly more current and hence costs more… (Of course many other differences matter too, but the noise difference is a big one.)

IMO the equipment needs to stay away from messing with the art. The equipment’s job is to present the art as faithfully as possible. (And to add color if that’s what the consumer wants, but if it can’t first deliver the original art or tries to substitute it’s own “art” that’s bad as far as most of us are concerned.)

What part of the my previous post wasn’t clear? Good equipment needs to be built by artists, but shouldn’t mess with the art that it is entrusted with.

Remember, you asked me what my process was. I believe it’s well founded on science and does what it’s designed to do reasonably well. I can’t ignore science as I work, the results would sound like crap.


Maybe some folks want a DAC to be mysterious art, but this is technology, and technology requires a sound scientific basis, otherwise it is voodoo, and voodoo doesn’t work.
Makes perfect sense to base it on maths to me - it is dealing with numbers after all, that’s what comes off the disc or streamer or whatever. It should reproduce the numbers as faithfully as possible.
Once it is analogue, then you can feed it through a Bascomb designed preamp or whatever, perfectly valid and something many of us do in one way or another, which will add whatever colouration you chose to make it sound nice to you, but the digital source should be (and in this case obviously is) based on sound science and maths.
Just my thoughts, thanks @tedsmith :slight_smile:

1 Like

I much prefer equipment tuned by science. Rather than by ear. Grado headphones boast of being tuned by ear and I really dislike their sound signature.

Thank you, Ted.

A thoughtful, interesting post which would have taken a good amount of time to put together.

Direct Stream Senior “DSS”(as opposed to the junior)
I see lots of posts referring to it as such.

Tuned by science? What does that even mean? Benchmark amps are built almost entirely based on numbers…and I absolutely hate the sound. Pass amps are voiced by listening to them because they know measurements don’t tell the whole story.


At least until it hits the analog conversion in the DAC itself, which is difficult to change out… IMHO that piece is particularly subject to critical listening.

Anytime we convert from one form to another, in this case, digital to analog, there’s always “art” involved because it’s an interpretation.

It’d be interesting to see if someone could map all the artistic styles of DACs and their creators to conventional art classifications (i.e. impressionism, art deco, art nouveau, etc.).

Agreed, analogue is rather different and subject to art as well as maths :slight_smile:

Thanks for the thoughtful and interesting reply. How does the noisy nature of tubes and vinyl correlate to the “low noise is always better” philosophy?

They are better with lower noise.


Haha @tedsmith :joy:! Is it possible the noise in tubes and vinyl add to the pleasing sound that some prefer over digital and solid state?

I’m neutral on this as I really don’t know. I do wonder how if lower noise is always better then how could these noisy actors have such a devoted following?

No. If it were easy to get rid of noise everyone would. The main thing you get for your more money after your system is good enough is lower noise.


Certainty is the enemy of innovation :hugs: