TOSLINK/SPDIF output board (project)

[kgallen]

Twin TOSLINK plus coax output board.

 

Transformer isolated coax output based on Sony MDS-E10 ‘pro’ output stage. The pulse transformer is the most expensive part by far (about 4GBP) but the PCB is padded out for a couple of options to mitigate against availability issues. 

 

This project is partially @BearBoy’s fault 😆👍
 

I subsequently found the part Sony use for the Coax RCA connector so I will redesign the PCB. I also missed one capacitor in the coax circuit. No real consequence but I’m a stickler for detail…

 

I originally designed this for my MXD-D4 to provide TOSLINK output from both the CD and MD sections. However with @BearBoy’s input I added the coax output and selection jumpers so it can be used with an MD-only machine and thus add twin TOSLINK and coax outputs.

 

Just a DIP 74HCU04 IC goes in the socket. 

 

[BearBoy]

Wow. That looks like a cracking piece of work, @kgallen. Really professional looking.

 

Will that work on any Sony deck with a single digital output?

 

And apologies if I was responsible for sending you down this particular rabbit hole 😲  😆

 

[kgallen]

It has to wire into a couple of points on the main PCB (or stuffed into the ribbon cable socket before @sfbp pulls me up on that one!). The machine doesn’t need to have any digital I/O on the back panel already. 

 

I’m only really familiar with the Sony machines and it should work with any as they use the SPDIF protocol natively internally. Otherwise this PCB has the interface drive circuits so doesn’t rely on the main board having any digital outputs already. 

[BearBoy]

Nice! As second hand deck prices seemingly continue to rise, it would be useful for closing the gap between the budget models (MDS-JE4xx/3xx) and their ever more expensive brethren...

[sfbp]

11 hours ago, BearBoy said:

Wow. That looks like a cracking piece of work, @kgallen. Really professional looking.

 

Will that work on any Sony deck with a single digital output?

 

And apologies if I was responsible for sending you down this particular rabbit hole 😲  😆

 

I think I may be the one that (indirectly) caused this. I am the proud possessor of its previous incarnation which is a simple 1->2 Toslink splitter, designed and built by Kevin.

The idea of adding the direct (coax) out is great, too. But I am happy with my gizmo regardless.

[Richard]

This looks fantastic Kevin - really neat! I wonder what the chances are of somehow being able to retrofit one of these into one of the Onkyo Hi-MD decks maybe 🤔

[kgallen]

Sorry I didn't realise the photos were so big - shrunk them now I've managed to get on the site via a PC and Firefox (rather than on a phone).

 

7 hours ago, sfbp said:

I think I may be the one that (indirectly) caused this. I am the proud possessor of its previous incarnation which is a simple 1->2 Toslink splitter

Indeed Stephen, that was the first project that made me dig into the TOSLINK circuits. This new project was originally pretty much that splitter without the input receiver and wired into the machine, but then @BearBoy and myself started discussing a coax output, so I looked into that and added one.

 

45 minutes ago, Richard said:

This looks fantastic Kevin - really neat! I wonder what the chances are of somehow being able to retrofit one of these into one of the Onkyo Hi-MD decks maybe 🤔

I'm not happy with the coax RCA socket on this v1 PCB since it doesn't have any mechanical support. The one Sony use has a screw that can be used to secure it to the case for mechanical support. The one I have used relies on the solder joints to the PCB (although I did pad out a large area of copper for mechanical support). Subsequent to sending off the PCB design for manufacture, I finally tracked down the part that Sony use (attached) and found someone on eBay selling some, albeit with the black insulator rather than the usual gold/orange for SPDIF. None of the mainstream suppliers here (RS, CPC, Farnell) stock this component. I think Mouser might list the range but I didn't want to buy a thousand or have one shipped from the US at great expense. Anyway I'm in the process of redesigning the PCB for that (larger) part, but I haven't fully tested this v1 design yet, so won't order a v2 design until that's complete.

 

Regardless, this board could actually be used sub-equipped as a single or dual TOSLINK output, and as long as your machine has SPDIF internally (which it will if it uses the Sony CXD DSP chips) and 0V and +5V then it can be fitted. The electronics is easy, it's the taking apart and drilling the back panel which is the hardest part.

 

I have some spare v1 bare PCBs if anyone wants one to play with. I'll let you know how I get on with the v2 and if anyone is interested, give me a shout. You lot might get a little prezzie anyway for your ongoing help and encouragement!

 

I suppose what I should do is do an "all features" PCB that can be a splitter or fitted internally to a machine with whatever combination of TOSLINK/Coax outputs you want. I guess this could end up being a bit over-engineered because the splitter needs a power supply and an input circuit whereas the output board doesn't require either.

 

However I guess the point is I know about all of the building blocks so if you fancy something, drops some ideas around. After all these little projects come about from suggestions/ideas/threads on here! 🙂

 

Boy, it's great to be back...

pjras1x1s_x_series_cd.pdf

[kgallen]

PCB v1 info for anyone who cares (schematic, pictures of PCB, Gerber files).

 

ETA: C30, C33 should be 100nF (0.1uF) NOT 100pf as on the schematic/BOM.

 

SPDIF Output.pdf PCB_PCB_SPDIF Output_Top.pdf PCB_PCB_SPDIF Output_Bottom.pdf PCB_PCB_SPDIF Output_Silk.pdf Gerber_PCB_SPDIF Output.zip

[EdinElk]

On 1/14/2022 at 7:35 PM, kgallen said:

It has to wire into a couple of points on the main PCB (or stuffed into the ribbon cable socket before @sfbp pulls me up on that one!). The machine doesn’t need to have any digital I/O on the back panel already. 

 

I’m only really familiar with the Sony machines and it should work with any as they use the SPDIF protocol natively internally. Otherwise this PCB has the interface drive circuits so doesn’t rely on the main board having any digital outputs already. 

Onkyo md 133 with sony kmk 400AAA and avaliable DOUT

[kgallen]

Hi @EdinElk, do you have a photo of the other side of the PCB?

 

Also I probably have some of my project PCBs (above) lying around - they are bare, unpopulated, you'd have to buy and solder the components of interest (all at your own risk!) If any use and you pay postage from the UK, then shout up.

 

Kevin

[EdinElk]

7 hours ago, kgallen said:

Hi @EdinElk, do you have a photo of the other side of the PCB?

 

Also I probably have some of my project PCBs (above) lying around - they are bare, unpopulated, you'd have to buy and solder the components of interest (all at your own risk!) If any use and you pay postage from the UK, then shout up.

 

Kevin

Hi Kevin,

Thanks, I'd be interested buying two-three PCB plus details or soldered boards, for testing toslink out from any of sony/onkyo Hi-MD players. I am near Coventry, so delivery is all right.

Could you confirm you have used with success only 'dout' and 'dground' Sony DSP pin connections to your board, getting spdif out?

Have you activated the spdif out in the service menu or via md desk uart?

 

Cheers,

Dim

 

[kgallen]

16 minutes ago, EdinElk said:

Thanks, I'd be interested buying two-three PCB plus details or soldered boards, for testing toslink out from any of sony/onkyo Hi-MD players. I am near Coventry, so delivery is all right.

Could you confirm you have used with success only 'dout' and 'dground' Sony DSP pin connections to your board, getting spdif out?

Have you activated spdid out in the service menu or via md desk uart?

Hi Dim.

 

(ETA I should have looked at your photo in detail first - I didn't!)

 

You don't have to buy them, you can have them for free. I probably got 10 in the PCB order and I've built one as the prototype so the others are sitting around.

 

You other question is related to a comment I've just made on the other thread. We need an SPDIF signal, not separate DAC/ADC clock and data, which is what I think we've got. The Sony decks I've looked at have the digital data in both formats on different pins of the DSP, so probably as the Onkyo uses a Sony DSP, the signal will be there, but I don't know if it's accessible.

 

So in answer to this question:

16 minutes ago, EdinElk said:

Could you confirm you have used with success only 'dout' and 'dground' Sony DSP pin connections to your board, getting spdif out?

then no, my board can't work with the clock plus data serial interface seen on e.g. the AK4524 DAC/ADC, my board is just a buffer and electrical interface where the deck already has SPDIF available, which as above is quite usual with the Sony DSPs, but possibly not guaranteed. This Onkyo probably uses the CXD2687 which is what I believe is used in the MZ-NH1 portable. It includes the integrated ARM controller. Since it's a fully integrated IC for a portable unit, quite possibly they didn't put an SPDIF interface on it? I'm not familiar enough with the CXD2687 to know off the top of my head. There does seem to be a Service Manual for the MZ-NH1 with schematics so with some study maybe the above questions could be answered.

 

I originally designed my board for an MXD-D4 CD/MD combo deck which uses SPDIF natively internally. The Philips DAC they use has an SPDIF interface which takes SPDIF from the CD and MD sections. This is generally different to the MD decks I've looked at which use e.g. the AK4524 DAC/ADC which has a clock plus data serial interface along the lines of the test points you've flagged on your photo. But then this decks almost always already have either TOSLINK or Coax SPDIF out, so piggy-backing on that to provide more outputs is easy.

 

16 minutes ago, EdinElk said:

Have you activated spdid out in the service menu or via md desk uart?

That wasn't necessary - the deck is already using SPDIF natively internally, so the signals are just grabbed from appropriate vias or component pads on the main PCB.

 

So in summary, more study of the Onkyo design is required to know how easy it is to add TOSLINK/Coax SPDIF out to these machines. Gut feel is if the DSP provides the output it should be perfectly straightforward. If it doesn't then it's a bit of a non-starter as a serial-to-SPDIF format conversion would be required.

 

Hope that helps... a little!

 

Regards,

Kevin

 

 

 

 

 

[kgallen]

I've finally gotten around to building and testing my v1.1 PCB of this project (yes, I know, it's been a while...). This includes the coaxial connector that Sony uses that has the chassis screw point and also includes some circuit updates to the coax/SPDIF circuit to match the MDS-E10 circuit. The optical and coax connectors are on the pitch that Sony uses on their machines (or at least the one I measured!). Sorry my photos aren't up to @Richard's standard. And thanks to @sfbp and @BearBoy for sending me down this rabbit hole! @EdinElk, thanks for hanging in there...

 

 

 

 

 

[jmsla]

On 8/25/2024 at 8:26 AM, kgallen said:

 

I've finally gotten around to building and testing my v1.1 PCB of this project (yes, I know, it's been a while...). This includes the coaxial connector that Sony uses that has the chassis screw point and also includes some circuit updates to the coax/SPDIF circuit to match the MDS-E10 circuit. The optical and coax connectors are on the pitch that Sony uses on their machines (or at least the one I measured!). Sorry my photos aren't up to @Richard's standard. And thanks to @sfbp and @BearBoy for sending me down this rabbit hole! @EdinElk, thanks for hanging in there...

 

Hello kgallen,

I have some active (self-powered) Alessis desk-top audio monitors the have USB input to receive digital audio from a computer's USB ports.  The idea being to have the monitor speaker's superior DAC, versus the computer sound card, do the the conversion to analogue for the cleanest signal to the the internal amp and actual speakers.  (The monitors do have analogue inputs as well.)

 

Am I only dreaming to imagine adding an optical-out to the monitor's internal USB module?  

 

The idea of having an optical out port right there at the monitor speaker, along with the audio to the speakers or headphones is tantalizing.  Having an 'always working' optical-out right there at the speaker, to send to a minidisc recorder, and still have the audio at the speakers is my desired goal. Even if the audio signal can't go to both an optical converter and the speakers simultaneously, I'd still be very happy. 

I have, ..Eureka! .., only recently gotten my Windows 10 computer to finally and reliably recognize my Xitel MD-Port DG2 usb to optical converter as the plug-and-play output device that ti is.  It's been a long and frustrating effort and I'm not convinced that the wonky Windows operating system won't start rejecting it again.   Plus, there is still a lot of fussing with the sound settings in Windows 10 in order to direct the audio to the Xitel and not the speakers.  (There is a way to get audio out through both a USB port and one of the mini TRS ports, but that adds even more risky fussing around.) 

 

I am not conversant in electronics lingo however, I notice you commented about your boards working on any portable minidsc unit because they all have 'optical protocol' built in but, it also seems you are saying that is really necessary. (?)

 

What do you think about the possibility of achieving my monitor speaker dream? 

If you saw the speaker's USB module and PCB board, and amplifier board, could you make an educated guess?   

 

I have several pair of Alessis M1 Active 320 USB speakers and a few pair of the larger 520 USB monitors so, experimenting on one or two of the powered speakers is no big deal.  I would not even have qualms about removing the USB module from one pair to add onto another speaker if that were necessary to make it work.  

 

Any comments will be gratefully received and appreciated.

____________

These Alessis speakers are inexpensive on the used market and I'll routinely buy up the cheapest ones I spot for backup and to scatter around my environment.

 

[kgallen]

Hi,

 

Plenty of products that already do that, for example this is really cheap:

 

https://www.behringer.com/product.html?modelCode=0805-AAG

USB to toslink is non-trivial so just buy an off the shelf module and integrate that. 

[jmsla]

3 hours ago, kgallen said:

Hi,

 

Plenty of products that already do that, for example this is really cheap:

 

https://www.behringer.com/product.html?modelCode=0805-AAG

USB to toslink is non-trivial so just buy an off the shelf module and integrate that. 

Thanks for the reply. 

First I'll mention that I spoke soon saying that my Win 10 computer was now recognizing my usb to toslink device, the Xitel Digital PC Link .  Again, the computer won't recognize it as a plug and play.  My old XP computer never had an issue with this device and still doesn't but, it's not on line anymore.    I can try something like that Behringer but, but it will come with a bundle of software and I suspect I'll have the similar problems getting it all to work with the Win 10 operating system.   

This is why I want to get the audio conversion to toslink a further step away from the computer so that it won't have to recognize anything except the speakers.  I should probably be grateful for that. 

I have even tried using the same usb cable connection that goes to the speaker for the Xitel, as I would at time with the XP computer, but Windows 10 just tells me that my speaker isn't connected.    They are both plug and play audio output devices. ??  It's maddening.

 

Anyway, I'll continue to try to figure out something that doesn't quire hours of reading fix-it forums, restarting my computer 3 times and logging on as Administrator just to record something playing online to a minidisc.  

 

[sfbp]

I've always gotten by with either a PCLK-MN10(/20) or a sound card that has S/PDIF. Most motherboards (non-laptop) have one of those on it these days. The only conceivable problem (to me) is that the MTB sound connections tend to be at 48 not 44.1 - but actually if you look at the Windows control panel it's quite easy to set it to the right sampling rate - thereby eliminating the possible problem of re-sampling from 48 to 44.1. This is actually only a real problem with LP playback, and since you want to record MD from an (?) online music source I don't see it's a problem at all.

 

The PCLK comes up and acts as a USB sound card with no software whatsoever, on all versions of Windows from XP thru 11.

 

You really shouldn't have trouble with this on a modern machine. If you have a laptop that has a. no "large" USB connections and b. no optical out, then I can highly recommend a sound card like Focusrite. The most basic will probably do, you will have to work out what I/O you need. It's a little pricey but fully supported with current versions of Windows. I'm sure there are el-cheapo versions from eBay, I had at least three different dongles costing about 10 bucks apiece. But not necessarily with opti-out.

 

This for example:

https://www.ebay.com/itm/115591309485

 

Stephen

[jmsla]

Hello sfbp,

The Xitel Digital PCLink MD-Port I have is basically the same thing but without the need for software or drivers, other than the generic usb drivers that are part of all operating systems.   

At one time Sony included the Xitel with certain minidisc recorders.   It worked flawlessly for me until Windows 10.  I think XP did see it as an external sound card or similar.  Windows 10 however, when not rejecting it, randomly calls it Speakers or USB audio CODEC or by it's model name MD-Port DG2.   Truly vexing is that the behavior is not consistent.  

 

Any yes, I often want to record to a minidisc something that's playing on-line like a radio station program, Live from Carnegie Hall or such or a lecture or music lesson that's on line, etc. (not a fan of on-line streaming services so, not that.)  

I don't want to have to reinvent the wheel every time and more often than not have it fail, which is what my Windows 10 experience is.   I just want to have a working toslink at the ready to plug into my minidisc and hit 'record'.

 

I  am familiar with many of the various computer / digital workstation interface gadgets that might also happen to have optical out.  The problem is with the Windows operating system.    I've reasoned that since my audio monitors are taking in a digital feed, why not try to add an optical output there at a point before the signal is converted to analog. 

For me it would be a perfect workaround for a wonky, unpredictable computer operating system; if it can be done.  That is my query.

[sfbp]

Windows' *only* problem with the sound system is that it basically allows for everything.

 

Here's a screen shot of mine:

 

What you see is that there are at least 3 ways of connecting to every device. This is for historical reasons, and Microsoft didn't want to invalidate any old software because they picked one of the earlier methods. And it all works, I have never yet seen a conflict or failure to do what I told it, no matter how many sound devices I connected.

 

In my experience they ALL work, especially on a decently fast modern machine. Even on older ones, the structure is all there. The "sounds" dialog allows you to pick input and output devices, (recording and playback) independently of each other. It allows you to pick the sampling frequency and various other parameters to the point where you don't even need a sound card app or program to tweak the Windows sound system

 

Fire up Zoom (which does its own manipulation of the sound devices) and you will see what i mean.

 

Xitel notwithstanding, the PCLK-MN10 has never failed to come up as a sound card. Maybe it(Xitel)'s an old (1.0 or 1.1) USB and the timing isn't very good on modern machines?)

[jmsla]

On 12/23/2024 at 7:37 PM, sfbp said:

Windows' *only* problem with the sound system is that it basically allows for everything.

 

Here's a screen shot of mine:

 

What you see is that there are at least 3 ways of connecting to every device. This is for historical reasons, and Microsoft didn't want to invalidate any old software because they picked one of the earlier methods. And it all works, I have never yet seen a conflict or failure to do what I told it, no matter how many sound devices I connected.

 

In my experience they ALL work, especially on a decently fast modern machine. Even on older ones, the structure is all there. The "sounds" dialog allows you to pick input and output devices, (recording and playback) independently of each other. It allows you to pick the sampling frequency and various other parameters to the point where you don't even need a sound card app or program to tweak the Windows sound system

 

Fire up Zoom (which does its own manipulation of the sound devices) and you will see what i mean.

 

Xitel notwithstanding, the PCLK-MN10 has never failed to come up as a sound card. Maybe it(Xitel)'s an old (1.0 or 1.1) USB and the timing isn't very good on modern machines?)

Sorry for the long delay replying; when it rains it pours; things got hectic for a for weeks. 

 

Anyway,  I've learned that others also have problems with their Xitel MD-Port on Windows 10 and 11 machines.  Something to do with some specific generic Plug And Play drivers that aren't always present on may machines.   Mine apparently must have these driver files because the device does work at times, just not reliably.    And i assume my active monitors with USB input must rely on the same generic drivers.  In fact when the MD-Port device is interfacing successfully with the computer , the computer identifies it as a playback device like an additional speaker. (?)

 

But, all that may be moot now as I have also learned that anyone can now record any sound that plays on their computer, from any source, with Audacity and , very easily.    That is even better because I end up with a tailor made audio track just waiting to be named and saved to a folder. Then import the track into Sonic Stage or similar program and transfer to minidisc.    No additional components and hook ups; just open the audio editing program Audacity, one or two clicks to put it in a 'loopback' capture mode and click record.  It will record for as long as you wish.

 

i am still intrigued by the idea of adding optical out to the USB input board in one of my powered speakers.  In that I have four of these Xitel MD-Port units, I can easily remove a circuit board and see if it's possible to wire it to the monitor's USB input board.  If I just knew how to read a schematic it might be easier.    If I should somehow succeed I will report here.   Thanks for all the input.

 

There is a picture of the Xitel MD-Port and its insides in the Minidisc Community Portal in the Gear tab ,MiniDisc Accessories Browser at USB Audio Adapters, near the bottom of the page.

[jmsla]

I should have added this as well if anyone is interested :  https://support.audacityteam.org/basics/recording-desktop-audio