Akai DPS24 ADAT expansion card woes: no audio

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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by OneWorld »

Do you have another audio interface you can try. I too use RME and I too get a no audio issue using one of the ADAT ports. I have some external effects which I want to use as insert effects, which use ADAT (in SPDIF - stereo) mode, I have set up the RME for ADAT to work as stereo, I had the red lights showing on the ADAT output, etc but try as I may I simply cannot get get the audio into the RME, in this insert effects scenario, but the ADAT works in other setups. It has to do with the patching or clocking I am sure.

I have given up and used the analogue i/o instead.

OK I guess this is a 'longshot' and quite often these 'have you tried' suggestions often lead you down a garden path and you end up given a dis-proportionate amount of time to something that will come to nothing but I suppose in the absence of anything else then owts better than nowt and it might be worth a try.

Best of luck. The DPS24 is a lovely machine and I suppose came along at the wrong time, when HDD recorders finally gave way to DAWs
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by James Perrett »

OneWorld wrote: Wed Oct 13, 2021 1:47 pm I have some external effects which I want to use as insert effects, which use ADAT (in SPDIF - stereo) mode, I have set up the RME for ADAT to work as stereo, I had the red lights showing on the ADAT output, etc but try as I may I simply cannot get get the audio into the RME, in this insert effects scenario, but the ADAT works in other setups. It has to do with the patching or clocking I am sure.

It may just be sloppy terminology but I just wanted to check... You can only run ADAT format signals in stereo if you are using a 192kHz sample rate. So do you have all the RME inputs and outputs set to SPDIF or ADAT? It should be SPDIF. Are you using the RME as the audio clock master and is everything else set to external audio clock?
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Hugh Robjohns »

There is a lot of confusion over the optical interface, and routine misnaming is a common cause.

The socket is identified in technical circles variously as the EIAJ RC-5720, the CP-1201, or the JIS C5974 F05 -- but probably the most common shorthand is the JIS F-05.

In consumer hi-fi circles it is more usually known as the TOS-Link socket, after the 'Toshiba Link'.

But just like the humble XLR-3, the socket itself doesn't define its function. The JIS F-05 is regularly used as the interface connection for either S/PDIF two-channel digital data or ADAT multi-channel data -- and many platforms allow the electronics to be configured manually to support either format.

In both cases, the S/PDIF or ADAT data carries embedded clocking data, so can be used as the clock source for the receiving device if suitably selected for that function.

Common reasons for non-working optical ports are:

* Wrong data mode selected.
* Wrong clocking source selected
* Multiple unsynchronised sources feeding the device simultaneously
* Excessively long or poor quality optical fibre
* Kinked or damaged fibre
* Dust or dirt in optical sockets
* Optical fibres connected to the wrong sockets (in/out reversed)
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Anthony gilbert »

Thanks for all the response on ADAT and optical.

For my DPS24 ADAT expansion card, the problem is quite fundamental as described earlier in the thread. To recap, the ADAT expansion optical-out ports x2 LEDs flash on boot, but then go out. The in-built ADAT optical-out port LED x1 happily glows red - and does so irrespective of clocks, config etc.

The control of the optical LED may well be done by the DS24, but perhaps acting on a control signal/state of the ADAT expansion. This is why I'm wondering is it the DPS24 or the expansion card?
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Hugh Robjohns »

Anthony gilbert wrote: Wed Oct 13, 2021 4:09 pm To recap, the ADAT expansion optical-out ports x2 LEDs flash on boot, but then go out. The in-built ADAT optical-out port LED x1 happily glows red - and does so irrespective of clocks, config etc.

I wouldn't assume that to be a fault. I have several bits of kit that turn off the optical outputs when not assigned (so the red light goes out). The Akai may be the same.

The control of the optical LED may well be done by the DS24, but perhaps acting on a control signal/state of the ADAT expansion. This is why I'm wondering is it the DPS24 or the expansion card?

As you mentioned earlier, you really need a current DS24 user to compare and confirm... Sorry I can't help, but I hope you get to the bottom of it.
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Anthony gilbert »

To recap, the ADAT expansion optical-out ports x2 LEDs flash on boot, but then go out. The in-built ADAT optical-out port LED x1 happily glows red - and does so irrespective of clocks, config etc.

I wouldn't assume that to be a fault. I have several bits of kit that turn off the optical outputs when not assigned (so the red light goes out). The Akai may be the same.

Hugh, that's worth knowing and very helpful. Thanks.
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by OneWorld »

James Perrett wrote: Wed Oct 13, 2021 2:07 pm
OneWorld wrote: Wed Oct 13, 2021 1:47 pm I have some external effects which I want to use as insert effects, which use ADAT (in SPDIF - stereo) mode, I have set up the RME for ADAT to work as stereo, I had the red lights showing on the ADAT output, etc but try as I may I simply cannot get get the audio into the RME, in this insert effects scenario, but the ADAT works in other setups. It has to do with the patching or clocking I am sure.

It may just be sloppy terminology but I just wanted to check... You can only run ADAT format signals in stereo if you are using a 192kHz sample rate. So do you have all the RME inputs and outputs set to SPDIF or ADAT? It should be SPDIF. Are you using the RME as the audio clock master and is everything else set to external audio clock?

That might be the issue then, as the external equipment does not have the 192kHz sample rate. It is not such a big issue as I am using the analogue instead
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Coz14 »

Hi Anthony - I think I might be able to help you out with your ADAT expansion card. I am in a similar situation as you which is how I found this post. I have a DSP24 which I bought in 2004 and still own. I have just upgraded my PC based DAW (Reaper) and wanted to use the DPS24 as a front end (Pre-amp and ADC) to send up to 16 tracks of ADAT to my RME HDSP 9652 soundcard.

Currently I am able to send 8 tracks via the DPS24's internal ADAT port.
Back in ~2012 I found/bought the ADAT extension board. The board worked for a little while but it was a bit flakey. Whenever I sent audio out on ADAT 9/10 the gain would increases in steps until the audio was distorting. Eventually out of frustration I hot swapped the board (removing and reinserting it while the DPS was still powered on), it stopped passing audio from that point. I fear/suspect that I may have damaged the Xilinx Spartan FPGA at the heart the board.

Recently, I have had renewed interest in seeing if I can get this card working again (or at least understanding/verifying what is wrong with it). This is what led me here. I saw your request for help, and I am willing to test your expansion card. If your are still interested in help, please reach out.

Steve
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Anthony gilbert »

Hi Steve,

Thanks for sharing your experiences. Very interesting read. Funny you mentioned the Xilinx Spartan IC, which I replaced. Of course it needs programming, so no board detection at all when I did this.

I'm not able to send the expansion card over until the new year, but I would love to see if you have any luck on your DPS24.

Send me a PM if you can for details.

Cheers,

Anthony
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Coz14 »

Hi Anthony - I am unable to send you a PM. I have not been given PM privileges yet, due to my lack of posts on this forum.

I just went back and re-read this thread and I have some questions. 1) Did your expansion card ever work properly? 2) When did you replace the FPGA, was this before or after you noticed the LEDs in the ADAT TX ports flashing/extinguishing? 3) Do you still have the original FPGA? As you have stated these IC's need to be programmed with the appropriate firmware. At this stage further troubleshooting is pointless without the original FPGA on the board.

Steve
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Sam Spoons »

Coz14 wrote: Sun Dec 26, 2021 3:27 pm Hi Anthony - I am unable to send you a PM. I have not been given PM privileges yet, due to my lack of posts on this forum.

Steve

One more approved post and your future posts will be auto-approved along with your PM privileges being activated.
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Re: Akai DPS24 ADAT expansion card woes: no audio

Post by Coz14 »

Anthony - I did want to pass on some more information. I don't know if you have any of the schematics for the DPS and/or expansion boards. Many years ago one of the guys on the DPS World forum posted the DPS24 schematics, board layouts, service manuals and software files. I checked and it appears that all this content is still available and can be found here:
http://steve.sideroadsband.com/DPS24/

To see the entire ADAT path within the DSP24 you will need the following four schematics:
"IB_24ADT_PC_ADAT" - this is the adat expansion board schematic.
"PC Mother" - this shows the connectors and wiring of the DSP expansion bay where the ADAT, SMPTE & SCSI card connect.
"PC CPU 2" - This shows the Internal Master FPGA (IC2) and where the Master/Slave FPGA communications originate. It also shows how the Internal FPGA is connected to the Internal ADAT TX/RX Ports.
"PC CPU 1" - This shows how the Master/Slave FPGA communications are sent from the CPU Board to the PC Mother via J201-J203 then ultimately onto the expansion card.

Using the schematics we can now work off of some of your observations. For instance the Adat LEDs that are flashing then turning off (As stated in a previous post, this is not normal. The TX LEDs on my expansion board always stay solidly lit, mimicking the TX internal port). We can see that the LEDs within the adat TX ports are simply driven from the 5v that the DPS supplies to the expansion board. If they are flashing and turning off, it would suggest that the DPS is shutting down that 5v line. This can be verified by probing the Sync connector with a multimeter on pins 3,4 or 5 (5v) and pin 1 (ground) at bootup.

Why would the LEDs flash and shut off? There could be many reasons (take my explanation below with a grain of salt. I am not an expert and I am learning this stuff as I go). Again looking at the schematic there are SPI communication signals going between the Master FPGA (Internal) and Slave FPGA (Expansion) these are denoted by MOSI and MISO (Master In Slave Out, Master Out Slave In). If there is a communication problem at boot up this could be throwing an error causing the 5v line to shut down. Also someone else in this thread stated that the expansion card may be good and the problem could be within the DPS, this is also a valid possibility.

The other day I removed my ADAT card and powered it up on the bench using a 5v power supply feeding Pins 1 (5v) & 14 (GND). I was able to verify that the board power was working find (Adat ports were powered, the 3.3v and 2.5v voltage regulators were working, the 50MHz clock was working). My next step is to figure out a way to instrument the board to see if IC communication is present and if digital audio is getting passed to the board.

I hope this helps.
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