I did a brief look last night for 12S to USB and found one card that claimed it could, but I did not find an off the shelf offering. It was late, so I may have missed something.
So does that mean the matrix, denefirps, and SU cannot? The back does not label any as input or output. I have to read the manual
EDIT: USB is the only audio input
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I wonder if I2S will be more common in 10 years?
There are a few good i2s output streamers available at all price points. My next one will be the “A Capella 3” for a 3rd system that is almost ready to go together.
USB has a physical concept of host and peripheral. What I mean by this is…
There is only ever 1 host on the bus and that’s specific chip / physical port. If physically it is a host then always a host (OTG changes this, OTG can negotiate). Everything else is a peripheral. For this reason, (USB-C is slightly different, see OTG) there are physical differences in the connectors between host and peripheral. Every DAC is a USB peripheral. Your computer / streamer is the USB host. For this reason, DDCs, unless they have both a USB host and USB peripheral port, cannot reverse this USB “input”.
That is… no, this won’t work…
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Thanks for the USB lesson. That sort of does limit the Airlens sales but I am sure Paul knows that and probably does not care. For me and most others here it will fit like a glove.
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On a tangential topic since we’re discussing DSD support on usb etc, my Lumin T2 specs says this. What does it mean? What does “native dsd512 support” here in the context of USB?
DIGITAL OUTPUT STAGE:
-
USB:
- Native DSD512 support
- PCM 44.1–384kHz, 16–32-bit, Stereo
I ask because I thought i2s is superior to usb for high rate DSD and that’s why PSA decided to use i2s (but then they’re limited to DSD256?!).
Here’s the full page
It means that the Lumin T2 DAC can receive and decode DSD 512 over its USB digital input.
AFAIK, none of the future PSA products have been described to support above DSD256 (Air Lens, DS2, TSS). I haven’t paid as much attention to TSS, but I think at least that’s true for Air Lens and DS2, which have been advertised to top out at DSD 256 based on what I’ve seen. If that’s not right, someone will correct.
The “UNIVERSAL SERIAL BUS DEVICE CLASS DEFINITION FOR
AUDIO DEVICES Release 3.0 September 22, 2016” specification includes a standardised way to send raw DSD audio streams without requiring you to smuggle them inside PCM-based streams using DoP. The Lumin device has support for this specification, so if any USB DAC gets connected that declares such support as well, you can transfer up to DSD512 over the USB cable.
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If ya got any extra Ribeyes I’ll gladly relieve you of them…. 
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I’m not sure what kinds of possible answers you’re expecting, but thankfully the actual answer is straightforward.
The coax output is SPDIF with a max rate of 192kHz, so you can smuggle DSD64 inside 24/176.4 but that’s the limit.
The I2S standard has a little bit of flexibility but is still PCM-centric. There are four wires in the spec: a master clock (like directly from a crystal), a bit clock, a L/R word clock and data line. The data line carries nothing but (PCM) audio samples with no spaces in between, alternating between left and right channels as signalled by the LR clock line switching between high and low. Getting DSD through this standard scheme requires DoP but there’s no logical limit as to how fast you run it – the practical limit is a matter of signal quality and processing speed. The AirLens will absolutely support doing this for at least DSD64 and DSD128. It might be capable of DSD256 in this manner.
There’s also a not-officially-standard way to send DSD over the same physical I2S connections. You just send one DSD channel stream down the data line and the other down the LR clock line. A DAC which understands this scheme notices the rapid changes on the LR clock line and interprets the incoming streams as two channels of DSD on separate lines instead of interleaved samples of PCM on a single line. The AirLens almost certainly will support doing this up to DSD256 and could likely go higher.
The not-official DSD native signalling is actually less demanding. For DoP128 the I2S data line needs a bandwidth of 16.9344Mbps and DoP256 is double that at 33.8688Mbps. Native signalling over two wires simultaneously runs at 1/3rd the speed! 5.6448Mbps for DSD128, 11.2896Mbps for DSD256 and only 22.5792Mbps is needed for DSD512.
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Getting past my wife will be your first challenge.
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Ok here’s my question/confusion: so far in this thread I’ve been hearing why you want i2s for high rate DSD (which I’m perfectly willing to accept) and superior to USB. But then I read that DSD512 is “natively” supported over USB on my T2.
So why is PSA trying to reinvent the wheel with i2s? I’m sure there’sa good reason, but am missing it. Cost? That for whatever reason, PSA didn’t make the DS DAC extensible/flexible to accept >DSD64 or 128 over usb, so now they have to use i2s?
Because getting the data where you want it is only half the challenge. Turning that data into perfect audio is still really hard, and the presence of USB makes it significantly harder. In the DS Mk I the XMOS USB receiver chip and its supporting circuits introduce an amount of electrical disturbance into the system that causes audible degradation of sound quality on the DAC’s outputs. Using the I2S input on that DAC avoids that specific problem.
The DS Mk II intends to have a better-performing USB receiver section. It will be interesting to see how that competition plays out: will AirLens and I2S be a more compelling partner for the DS Mk II than something like a Lumin T2 and USB? Totally unknown at this point. But at least PSA will have an offering in their stable which will definitely perform at a very high level and will enable Roon etc on all their DACs.
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I should add: I2S is the “native” communication format for things inside the DS DAC. In fact the path between the USB receiver section and the FPGA is I2S. So having external I2S inputs is a very trivial thing to include on the DAC side.
So would Lumin have the same issue as the AL + DS DAC with usb combo? And Lumin decided to compromise and allow the interference at the DAC output? Or because they integrated both the chipsets of the streaming and the DAC they avoided it somehow?
I dunno. I was kinda excited about the AL replacing my Lumin but now I’m of two minds. I’m somewhat feeling that I’m going backwards if I’m limited to DSD 256 with the AL.
And do I really want to spend yet another 2k or whatever for the AL to find out whether it’s better than my Lumin?
I’m not sure specifically what you’re asking in that first sentence. The Lumin transport can’t mitigate the weaknesses inherent in the DS DAC’s USB receiver circuit. Other DACs claim to have engineered past the challenges of USB inside their DACs (thinking about Holo here in particular) but we’re waiting for Mk II to see if Ted can make similar assertions.
The DS DAC Mk I only supports up to DSD128 via USB and up to DSD256 via I2S. Lumin doesn’t help you get past that and AirLens won’t hold you back. I’m very very confident that AirLens will sound better than anything connected to the USB input of the DS Mk I.
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No ranches nearby, but there are a couple of Costco within 15 minutes; works for me.
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I asked Paul McGowan a specific question:
“Will and how will the AirLens transmit higher rate DSD to PSA and/or other DACs?”
And you wrote:
“With a DDC, which for max results needs an LPS, powercord, and good DC and USB cable. So yeah more money. Basically what most of us here with the DSD have been doing to get streamers w/o I2S are doing now.”
My response/question to you was intended to understand how you learned the information you provided because, frankly, I believe you are mistaken.
I don’t recall PSA/Paul ever mentioning the need for a separate piece of kit to handle higher rate DSD, but I know Paul is keen on DSD in general.
Upon further reflection, I suspect you misunderstood my question.
Best regards.
So the Lumin is a streamer and DAC combo that has a usb input. And handles DSD 512.
What I’m saying is that if I get the AL, connect it to my existing DS DAC mk I I’m limited to DSD256 max.
In that sense it’s a step backward. To fix it, because I believe that a PSA system will sound better, I need to spend money on both a new AL and maybe a new DS DAC mk 2 (assuming it fixes the usb issues) to find out whether it can handle DSD 512 and sounds better than my current Lumin. That’s a lot of money to try to find that out.