Optical input on DS: 24-192 not working


#1

Having a strange issue here. Been testing out the Coaxial and the Optical inputs on the DS, streaming from my Oppo using bitstream mode (bypasses the internal Oppo Dac). Coaxial works fine with 24-192 files, but the Optical input is not functioning with 24-192 files (red dot on the front panel) Maybe there is a setting in the Oppo that I have missed? 24-96 files work fine. Any ideas?


#2

Sure. The toslink input on the DirectStream is only speced to 96k. Anything higher is purely a happy accident.

J.P.


#3

Thanks wingsounds, didn’t realize that. What is the reason for the toslink only speced to 96?


#4

All TOSLINK cables have that same issue, not just the one’s we use. It’s why Toshiba has announced the end to TOSLINK.


#5

Wasn’t there a legal limitation as to what could be passed over Toslink? Those limitations really painted them in a corner - which is too bad, because I think the optical separation of devices is a great idea.


#6

The limitation is completely technical in nature. If there was a legal limitation it would have been a separate issue.


#7

Optical fiber is a superb interface and it is indeed unfortunate TosLink is technically insufficient. It was developed in the 1980’s and was never expected to carry the datastreams we see today. It also has the unfortunate reputation as being deficient, probably as a result of its presence on most consumer devices and the cheap implementation on such units.

There are high quality alternatives, such as Bel Canto’s ST-optical interface. The optical transmission lines used in telecommunications are also vastly superior.

Stepping back, I continue to find it astounding we can transmit information on light - science fiction a generation ago.


#8

And I have fiber (fios) running into my home tha covers my multiple TVs, phones and very fast internet connections, all at the same time. Amazing indeed. My old Wadia 860/861 has the so-called AT&T glass fiber connectors (in addition to coax on BNC and Toslink) but I never had anything to hook up that way.


#9

I’m really sad to hear that the DS doesn’t support 192kHz on the optical input :(

The biggest weakness of optical for most audio is the jitter due to imprecise edge detection. The DS clock management makes that a total non-issue as far as I can tell… meaning you have a 100% electrically-isolated input.

In a weekend audition I found the DS to be more sensitive to USB cables, coax cables and components upstream of both than I would like. I was seriously thinking about partnering a DS with a Peachtree X1 which is a USB-to-SPDIF converter with dual clocks and support for 192kHz on both coax and optical outputs. It was my hope that the optical input would let me play anything from 44 to 192 and even DSD64 with total source immunity.

Toslink was the DS’s best-sounding connection in my test, though my poor quality 3.5mm-to-toslink adaptor meant I couldn’t test with anything higher than 48kHz. I’d like to hear from others whether you’d agree with me about optical being a good thing on the DS.


#10

It isn’t DS that won’t accept it, it’s the cables, the optical receiver and transmitter made by Toshiba. This system was never designed to pass anything higher than 96kHz. Then older glass cables certainly will, but there are few, if any, sources available to send data through those connectors; thus no reason for us to include them on DS.

Toshiba is abandoning the TOSLINK category altogether for this reason. It’s not DS.


#11
dvorak said I'm really sad to hear that the DS doesn't support 192kHz on the optical input :(

Toslink was the DS’s best-sounding connection in my test, though my poor quality 3.5mm-to-toslink adaptor meant I couldn’t test with anything higher than 48kHz. I’d like to hear from others whether you’d agree with me about optical being a good thing on the DS.

I have similar results in my testing. I'm using an Audioquest Diamond toslink from my Oppo to the DS, and it sounds fantastic. Better than the bridge in my opinion. Oppo much more stable as a streamer as well. I'm using a Shunyata Cobra coaxial for the 24-192 files, and it has a bit less air and dynamics than the toslink. The bulk of my hi rez are 24-96, so I can live with this.

#12
Originally, my 1st generation PWT only worked up to 176.4 Khz with toslink connected to the DS.
That PWT recently needed a new IDE drive but PS Audio only had SATA drives and that required a new generation "FPGA" board be installed.
Much to my surprise, 192Khz now works fine with the updated PWT outputting toslink to the Direct Stream.

#13

Interesting. This is pure luck, but great luck. :)


#14
Paul McGowan said It isn't DS that won't accept it, it's the cables, the optical receiver and transmitter made by Toshiba. This system was never designed to pass anything higher than 96kHz. Then older glass cables certainly will, but there are few, if any, sources available to send data through those connectors; thus no reason for us to include them on DS.

Toshiba is abandoning the TOSLINK category altogether for this reason. It’s not DS.


Forget about Toshiba. High rate SPDIF data over optical is totally viable, if your optical transceivers, connectors and cables are up to it. Newer model MacBooks do 192kHz optical out from the 3.5mm audio jack. Peachtree’s X1 is $149 and it does 192kHz optical out on a Toslink connector. You can get a $60 unit from China (diyhifishop) with the same capability. Bel Canto and others ditch the Toslink hardware in favour of ST type connectors on their 192kHz optical digital audio interfaces.

High speed optical of some form seems like the ideal way of getting data into the Audio Decoding Engine or whatever that phrase was. No noise, zero sensitivity to edge jitter, just the pure data.

Based on my testing with the DS (it sounded incredible!) I’m wishing I could buy a model which swapped one or more of the AES and I2S inputs for more optical inputs including one which could carry DSD128. For now I’m saving up for today’s model and will make heavy use of Toslink with an external switch box for my various sources.


#15

Hey Paul, Ted - I was just googling around and came across the old Wadia 931 and 922 combo (http://wadia.com/en-us/products/older-products). There’s a concept there built around optical connections which could be utterly awesome for future DS evolution.

Put the FPGA, clock and output stage of a DS in a box. Give it just a single ST fibre optic input with transceivers fast enough to support up to DSD128. Balanced and SE analog outputs as today. A USB port for firmware updates only, and probably no display.

The really interesting part revolves around what device is sending the optical data. So many options, ranging from an inexpensive USB-to-ST converter for dedicated media server / PC use, through to another big PS Audio box with a whole bunch of inputs, touch screen and remote control. Possibly even with four optical outputs to connect to four stereo DS DACs in order to handle 7.1 surround.

As icing on the cake, embed per-channel attenuation level and maybe even high/low-level output toggle commands in the user data bits of the AES/EBU or S/PDIF subframes. That would permit volume/balance setting to be controlled from whichever user interface which made the most sense in the context of the playback system while still passing bit-perfect data (including DSD) and leaving the actual attenuation up to the FPGA code.

Dreaming, I know, but maybe you’ll find something worth looking at in those ideas.


#16

I just connected a Squeezebox Touch with EDO applet installed to a DirectStream DAC via a decent but cheap plastic optical cable and was able to play 192kHz PCM content just fine laugh


#17

How is the sound quality from the Touch into the DS? Still have one in the back of the closet somewhere, maybe I’ll dig that out as you have perked my curiousity.


#18

It’s so good. You have to try it. It sounds equally perfect with any source which is capable of sending it the right bits, and I am convinced it’s the best input on the DS.


#19

Have you tried sending DoP?


#20

From the Squeezebox? No.

Via optical? Yes. Late 2013 MacBook Pro supports up to 192kHz on its built-in optical output, which is fast enough for DSD64 in DoP. Sounded fabulous.