24/192 toslink on DS


any reason why this is not supported? The nuwave dsd dac does support 24/192 toslink input so the technology is available …

i should mention that i did test 24/192 toslink from my macbook pro retina to DS and it does not work. The latest macbook pro retina supports 24/192 toslink output.


TOSLink was original designed for 48k, but in general works for 96k. If the quality of the TOSLink receiver and transmitter are up to it and you use a reasonable quality (and not too long) optical cable you can get 24/176.4 or even 24/192. I use it here, but as I said it depends on your source’s capabilities and cable as well.


Hi ted

do you mean if i use an appropriate toslink cable i can get 24/192 on my DS?


Probably - if a cheap plastic TOSLink cable doesn’t work a slightly better glass fiber probably will. I use a next to the bottom of the line AudioQuest TOSLink cable, the bottom of the line cable did 176.4k reliably but not 192k.


The practical limitation of “TOSLINK” is in the photo-electric/electronic characteristics of the transmitting and receiving components into which we insert the plug ends. The TOSLINK spec only requires them to support an “NRZ baud rate” of 16 megabits per second. If that’s as fast as your device’s components can convert electricity to light and back again, the highest standard SPDIF signal rate you’ll achieve is two channel 24-bit 96k.

When components are manufactured, just by luck some of them end up being capable of exceeding the minimum required specification. So some transmit/receive components sold as 16Mbps parts are capable of running at higher speeds. I have a four-way active TOSLINK switch box which uses parts rated to 16Mbps but I can reliably send 176.4kHz PCM or 1xDoP signals through it into my DS which likewise is guaranteed only to 96k.

If I take the switch out of the system and use a cheap plastic cable that isn’t too long I reliably get 192kHz from my DAC. That requires a baud rate of 24.576Mbps NRZ.

Some component manufacturers (but seemingly not those licensed to sell TOSLINK parts in the USA) offer parts guaranteed to support up to 25Mbps. PS Audio unfortunately doesn’t – perhaps can’t – buy those parts. But sometimes we get lucky.


I tried VDH optocoupler mini toslink to toslink, doesn’t get me 24/192. But the same cable gets me 24/192 on a McIntosh C2500, which toslink input was also specced as 24/96. Sad.


Interesting thread, though.


The best Toslink that I have found is made by Sys. Concept Inc.

1300 strand glass.

They state that their cables are 24/192.

Just about any combination of Toslink terminations.

Very reasonably priced.

Check them out.


When it comes to the cables, the only important factor is how much of the signalling light is lost through the cable, and how much external light can creep in through the connectors etc.

Frequency is absolutely NOT a limitation for the cables. Toslink works with red light at a wavelength of 650nm, which is another way of saying that the light’s frequency is 461.2THz. That’s 461,200,000,000 kHz.

The component limitation I talked about in the previous post is to do with how quickly the semiconductor pieces connected to each end of the cable can switch between on/off states when converting electricity to light (transmitting) or light to electrical conductivity (receiving). The cable needs to pass as much of the transmitted light through to the receiver as possible, while avoiding allowing extraneous light to enter through the connectors, so that the receiving semiconductor can accurately track the on/off signalling of the transmitter.

Plastic cables lose light strength at a rate of approximately 1dB per meter. Glass cables lose light at a rate of a fraction of a dB per KILOMETER. By losing less light in transmission, glass cables can provide the receiving semiconductor with more light to help it more accurately track faster switching between on/off states. That’s all.

With the right semiconductors for transmission and reception at each end, our common plastic TOSLINK cables would support any conceivable audio data transfer rate, no problem.


Except TOSLink was first of all designed to be cheap - hence low bandwidth semiconductors on both ends and it expects cheap cables so it assumes a certain loss in the cables. There are plenty of higher bandwidth optical transceivers and cables out there, but they cost far more, and in the case of audio aren’t “standard”. Some TOSLink transceivers appear to be so cheap that too good of a cable may not attenuate the signal enough and hence overdrive them and cause more problems than other more lossy cables. As a practical matter having a few different quality/style cables on hand can be useful when the connection isn’t what it could be.


Interesting. So…

  1. did anyone successfully get 24/192 to work on DS? Please report on cable used

  2. why is nuwave dsd specced as 24/192 toslink but directstream only specced as 24/96? Does nuwave have a better toslink receiver?


Ted - in practical terms, that is all true of course. The point I’m making is, it doesn’t make sense to ask whether a cable can “support” 192kHz digital audio transmission, because all of them can. Whether or not they work successfully in a particular system is a function of the semiconductors, as we both have stated now in different ways.

I wasn’t necessarily promoting glass cables for toslink, by the way. Just trying to explain why there might be different results from using different cables and different devices.

Andy - my DS works at 192kHz from MacBook Pro and SqueezeBox Touch with a variety of cheap plastic cables between about 2 and 4 feet long. If I put a passive optical switch in between two cables known to work as above, the light loss is so bad that I’m lucky to get 88.2kHz signals working. With an active optical switch in the same position which uses components specced by the manufacturer to support only 96kHz, I can reliably get 176.4kHz and therefore also 1xDSD playing through the DS DAC, but 192kHz fails. In that case it’s clearly the semiconductor pieces in the active switch which are letting me down.


IMO one of the biggest mistakes made by the industry was not working with companies like AT&T to figure out how to make ST glass the ongoing standard for audio over fiber. Early on some companies like EAD, ML, and Wadia outfitted their gear with ST optical interfaces. Best thing ever, but apparently the cost put it over the line for trickle down to less expensive DACs and transports. It’s amazing how the course of a hobby can change so drastically (and badly) for want of a few dollars.


Agreed. Bel Canto employs AT&T ST-Type glass optical in its Black System. It works beautifully.



with the only comment that I would prefer SC (or rather LC) to ST.


Many dacs work fine up to dsd 128.

An expensive optical cable is not needed.

May msb , Hugo and ds work fine up to dsd 64 from the output of my plat plus player

i think it’s the source here being the limiting point

the Hugo comes with a cheap no name that works fine.

And tto add insult I bought a cheap 24 inch cable from my electrical supply house complete with fittings to be apple or standard toslink It even came with 90 connectors that snap on. I also own a expesive audio Quest one and some other multi k strand one too.

A complete waitst for me and pure pride of ownership. Source rules for me.

Sorry but until I can hear different then this is what I will say for my observations

It fitting proper inside the slot is paramount


I’m wondering how many people has tried toslink with the DS? I pulled out my old Oppo 981HD from the closet and a $5 cable from Amazon and at least for CDs it is amazing. In my system it beats the Bridge II which in itself is very good.

I would like to try burning some discs with higher resolution files. Can anyone direct me to a process (softwares) to do that on a Windows 7 (64 bit) computer,


I used TOSLink for all of my demo’s for the prototype, including the one I did for Paul. More than once other DACs couldn’t even lock onto the signal from my crappy USB to TOSLink converter. TOSLink has a big leg up on any copper connection with their radiation, EMI and ground loop issues.

largenmt said

I would like to try burning some discs with higher resolution files.

For playback on a PWT or on your Oppo?

For the PWT, one needs to be certain to use the proper version of UDF when burning the DVD – UDF 1.02. This is important as this is what the PWT expects. See, click, for exemplar instructions.

I do not know what the Oppo expects to see.


Ted has said that all the inputs sound good or even close to the same

Ted does not lie and as I really do not trust what a designer or Owener says I can with Ted and Paul. Also as I was a beta tester for the bridge two from my server it’s sound was on par with its usb meaning very good

if your bridge is out done by optical that’s good but you need to try and find out why.

And I am glad to read a 5 cable can sound so damn good

Ted knows technically why but I have found that in certain circumstances optical is a big improvement over coax or usb.

Also read the regen thread it’s really with a try too