Akai DPS24 ADAT expansion card woes: no audio

[Anthony gilbert]

Hi everyone, first post and starting with a long-shot, but here goes:

Problem: Akai DPS24 ADAT expansion card. Recognised by system, accepts ADAT optical sync, but no audio in or out.

I've had the DPS24 for over 10 years and still enjoy using it. It's primary function is now as a mixing desk using the onboard ADAT for essentially 8-channel "passthrough" to an RME <Digiface USB> ADAT interface to my MacBook and Logic.

I now want to go to 24-channel passthrough, as the RME has 4 ADAT ports.
I've added the Akai IB-24ADT 16-channel ADAT I/O card, which is detected by the DPS24 as I now have 24 channels displaying in the various patching / routing screens.

The problem is I get no audio - either in or out. I have spent the last year (I know) trying to get this to work. Items covered:

• Various tests concerning optical sync. It can sync to an input on either ADAT 9-16 or 17-24 in setup.
  I have cleaned the connector using expansive Deoxit.
  I have performed basic functional tests on the expansion card, including the onboard 3v3 and 2v5 regulators, and capacitor and resistor short / open circuit.

I have even looked for a second ADAT expansion, including a "Wanted" advert in SOS readers ads.

Time then to ask if anyone has had experience with the DPS24 ADAT expansion card?

• Anything similar?
  ADAT IB-24ADT card to sell?
  Do you have a DPS24 and are happy to plugin my expansion card to test?

Any help very much appreciated!

[FrankF]

Some obvious stuff:
Have you set up a custom patch preset in the PATCH menu?

Are you getting "error...audio muted" messages? See above!

I had mine set up with 2 audio interfaces a couple of years ago, and it worked fine, so I can't see what the problem is. Oh yes, there's also an option in SETUP, but I'm guessing you've tweaked that already.

When you say that the ADAT card is "recognised", how do you mean? I could have a look at mine to see if there's any difference.
Feel free to PM me with some screen shots if you think it will help.

[Anthony gilbert]

Thanks Frank for your quick response - I didn't hold much hope!

To answer your questions:
Have you set up a custom patch preset in the PATCH menu?
Yes. The patch menu is essentially where I have determined the expansion card is recognised, as it provides the option of ADAT channels 9-24.

I have created a custom patch, and have also tried the preset "24 track ADAT transfer".

Are you getting "error...audio muted" messages? See above!
No, I can enter the setup menu >Digital Sync, and successfully sync to ADAT 9-16 or ADAT 17-24 inputs.

With the expansion card removed, these options disappear in the patch menu, and of course no sync, with the usual "error...audio mute" message...

[James Perrett]

One basic thing that sometimes catches me out - are you using the same sample rate in the DPS24 as the external input? What clock source are you using?

[FrankF]

Ah yes, James has reminded me of another "tweak": when I had both the Behringer and Focusrite i/fs connected, one of them would only work as Master (can't remember which one).

That was with 2x8 out interfaces - are you using just one or more than one interface together?

[Anthony gilbert]

One basic thing that sometimes catches me out - are you using the same sample rate in the DPS24 as the external input? What clock source are you using?

Hi James, thanks for your interest and help.

Over the last 12 months I have tried internal and external sync options covering both inputs and outputs, samples rates and bit depths.

The 2x most basic tests I have used for input testing are as follows:

1) Use built-in DPS24 ADAT as an output to ADAT expansion input. DPS24 Internal clock, 44.1khz, 16-bit. That in my mind should be the most basic of tests using the DPS24 clock and most basic sample rate settings.

2) DPS24 Patch Preset 24 track ADAT transfer. I arm all the tracks. I have an input clocked to the DPS24 internal clock. I have audio playing and plug an optical cable into the built-in ADAT input channel 1: it works and I hear audio. I then take the same optical cable and plug into the ADAT expansion card, no audio.

I have also tried more complex tests on outputs using internal and external sync.

[Anthony gilbert]

Just to add: I would be happy to post the card to anyone who can test it.

[forumuser840717]

It's several years since I had a DPS24 but I used to have two of my own and look after three others for a local hopsital radio station that used them as location recorders and as production workstations. They all had the ADAT expansion, LTC and SCSI options fitted and all worked fine with either external mic preamps or HD24/XR machines feeding 24 channels to their ADAT inputs. Which doesn't help you.

So, if your DPS24 sees the ADAT expansion card and shows the extra 16 channels i/o iin it's patch setup, and it will sync to any ADAT input, including those on the expansion card then that suggests that the card is working (though it could be fibbing!) but some random thoughts:

I guess from you mention of wanting to increase your channel count, that you can send 8 channels of audio from the RME to the DPS24 using the DPS24's internal ADAT port?

If so, have you tried taking that ADAT link, which you know is good and working, into one of the expansion board's ports (and, of course, selecting that as the clock source)?

[forumuser840717]

Over the last 12 months I have tried internal and external sync options covering both inputs and outputs, samples rates and bit depths.

The 2x most basic tests I have used for input testing are as follows:

1) Use built-in DPS24 ADAT as an output to ADAT expansion input. DPS24 Internal clock, 44.1khz, 16-bit. That in my mind should be the most basic of tests using the DPS24 clock and most basic sample rate settings.

2) DPS24 Patch Preset 24 track ADAT transfer. I arm all the tracks. I have an input clocked to the DPS24 internal clock. I have audio playing and plug an optical cable into the built-in ADAT input channel 1: it works and I hear audio. I then take the same optical cable and plug into the ADAT expansion card, no audio.

I have also tried more complex tests on outputs using internal and external sync.

Re. your testing scenarios, I'm wondering whether you have a clocking issue:

1. I never tried it but I'm fairly sure that looping the DPS24's clock from it's ADAT out to the expansion card's ADAT in isn't helpful as the unit needs either to clock from it's internal clock or, in this instance, one of it's ADAT inputs. If you patch the output to an input and try to sync to it, you'll likely get a clock loop which is very rarely a good thing as the DPS24 will try to chase itself. Far better to take a known working ADAT source and try that into each ADAT input in turn. If it works as a clock (and audio) source into the DPS24 internal ADAT input then it should work as a clock (and audio) source when plugged into the Expansion card's ADAT inputs (you'll need to set the DPS24 clock source to the appropriate ADAT input too).

2. You say " I have an input clocked to the DPS24 internal clock." An input of what? The RME?
If the DPS is locked to it's internal clock then the RME will need to be locked to an ADAT return from the DPS24 - which will (or should) work fine. However, if the DPS24 is set to Internal and the RME is not locked to the same clock (via an ADAT return) e.g. it is also set to internal then you have a problem.

[Anthony gilbert]

If so, have you tried taking that ADAT link, which you know is good and working, into one of the expansion board's ports (and, of course, selecting that as the clock source)?

Yes, and it also strikes me as a robust test for the reasons you have given.

Thanks for your help on this. 3x DPS24 for hospital radio location and production workstations sounds impressive - well above what I would have imagined.

It's a very strange fault, and I do wonder about the DPS24 itself as being the fault. The expansion cards plug into a separate PCB on the DPS24 which has small interconnections back to the main PCB:
J201 (20-way), J202 (26-way), and J203 (28-way).

That's a lot of connections - and possibly we are seeing the data-bus and addresses connections working required for detection and clock sync, but another connection failing on the audio side - albeit this would be digital (data) connection at this stage.

I don't have the other option cards, otherwise I would know more about the idea above being valid - given they share the same data-bus and addresses connections.

[forumuser840717]

Another vague memory is that "DPS24 Patch Preset 24 track ADAT transfer." has some odd features. Iirr, it's a special patch that routes all ADAT input channels directly to the Disk Record Sources for Tracks 1-24, and the DPS24's Tracks 1-24 to the 24 ADAT output channels. I vaguely remember (and could well be wrong about this) that In this mode, the inputs go direct to the Tracks (Track Record Sources) and not via the mixer, with the 24 recorder tracks going to the ADAT outputs via the mixer. There was also something about needing 24TK RECORD mode switched off for "24TK ADAT Transfer" to work or the last four channel outputs don't happen to the ADAT outputs.

Have you tried using one of the 'normal' routing setups (with 24TK RECORD turned on if you want to record 24 tracks)?

[Anthony gilbert]

If the DPS is locked to it's internal clock then the RME will need to be locked to an ADAT return from the DPS24 - which will (or should) work fine.

Thanks again. This is a good point, and worth covering below:

Sync results
ADAT Inputs
The onboard ADAT input will sync successfully to an external clock.
The ADAT expansion input will also sync to an external clock.

All seemingly OK. but...

ADAT outputs
My RME (using the onscreen Fireface application) detects the internal clock of the DPS24 coming from the onboard ADAT output.
The RME doesn't detect the internal clock of the DPS24 coming from the expansion ADAT output.

***breaking*** something I have overlooked. The red-LEDs of the expansion DATA output (TOSLINK) ports flash on for the first few seconds of boot up. Afterwhich they go off and stay off. If there isn't any optical port LEDs, then surely cannot be any valid output?

This doesn't explain the lack of function when it comes to INPUTs, but certainly points to a fault with the OUTPUT ports.

Can I ask if anyone has the same? Do your expansion OUTPUT ADAT/TOSLINK ports flash for 3-5 seconds on DPS24 boot, and then they go off and stay off?

The lack of red-light on the output ports is possibly something quite tangible and a pointer... I think we're looking at faulty hardware somewhere - could be the card or DPS24 itself.

[FrankF]

All 3 OUT leds, internal, 9-16, 17-24 are solid red, from powerup onwards - that's with no ADAT cables connected.

I guess you've reseated the ADAT card a few times when cleaning the thing?

If you think the card's faulty, you could contact vstservices: I bought several DPS24 cards from them. They advertise on Ebay UK, but not everything they have in stock.

[Anthony gilbert]

All 3 OUT leds, internal, 9-16, 17-24 are solid red, from powerup onwards - that's with no ADAT cables connected.
.

Brilliant. That is most certainly different to mine, and makes perfect sense. My internal port stays on - why shouldn't the external?

I will contact VST services as suggested.

Thanks again.

[forumuser840717]

Sync results
ADAT Inputs
The onboard ADAT input will sync successfully to an external clock.
The ADAT expansion input will also sync to an external clock.

Does this work for both ports on the ADAT expansion board?
Also, when you get sync, do you also get 8 channels of audio on the appropriate port?

ADAT outputs
My RME (using the onscreen Fireface application) detects the internal clock of the DPS24 coming from the onboard ADAT output.

Good - that's what should happen

The RME doesn't detect the internal clock of the DPS24 coming from the expansion ADAT output.

Not so good. Though your explanation of the lack of any lights in the ADAT outputs would certainly explain it. (Incidentally, you shouldn't actually need to clock the RME from the DPS24 (though it's a perfectly valid way to work); everything should work ok with the RME acting as the master clock source (clocking internally) and the DPS24 set to use any working ADAT source from the RME as it's clock source.)

***breaking*** something I have overlooked. The red-LEDs of the expansion DATA output (TOSLINK) ports flash on for the first few seconds of boot up. Afterwhich they go off and stay off. If there isn't any optical port LEDs, there surely cannot be any valid output?

This doesn't explain the lack of function when it comes to INPUTs, but certainly points to a fault with the OUTPUT ports

Correct. One of the nice things about ADAT optical as a format is that it uses visible light so no light in the output socket is a good pointer to no signal.

I don't have one here to check but I'm pretty sure that the ADAT outputs on the expansion board should light up continuously in the same way as the DPS24's internal ADAT output does. The lights going on at boot up does suggest that if there's a fault it's not with the LEDs but them not staying on suggests that something is wrong elsewhere.

Bit of a random one - have you tried removing the card, checking carefully for any bent or broken pins in the edge connector and then re-seating it? (And doing the same to the ribbon cable joining the expansion card back plane sub board to the main board.)

[Kwackman]

Red Herring time....
ADAT can be 8 channels of audio, or a single stereo feed.
From memory RME can switch between these modes in software.

Probably not relevant, but, just in case!

[Drew Stephenson]

Red Herring time....
ADAT can be 8 channels of audio, or a single stereo feed.
From memory RME can switch between these modes in software.

Probably not relevant, but, just in case!

Just to be picky...
The toslink optical connection can carry ADAT or SPDIF. ADAT can be up to 8 channels depending on sample rate. SPDIF is always stereo.
The socket is the same but the configuration isn't and needs to be set accordingly.
[/pedantry]

[Kwackman]

Just to be picky...
The toslink optical connection can carry ADAT or SPDIF. ADAT can be up to 8 channels depending on sample rate. SPDIF is always stereo.
The socket is the same but the configuration isn't and needs to be set accordingly.
[/pedantry]

Drew, have you not got anything better to do, like spotting frequencies in choirs no other humans can hear?

PS. You are correct of course, that was very sloppy terminology on my part.
I'll be in the corner huffing for the rest of the afternoon......

[Drew Stephenson]

I'm sorry about the choir thing too.
But it's definitely there.

[forumuser840717]

Yep, and all the RME's optical ports can function as either ADAT Lightpipe or SPDIF ports, as can the TOSLINK connection on the DPS24 itself. Hence asking whether there was a known working link passing clock and ADAT audio to use as a test source. I wondered whether the RME or DPS24 might be set to SPDIF on all or some of the ports.

If everything were set to SPDIF then obviously they'd sync up but wouldn't pass 8 channels of audio (and they'd show up in the DPS24 patch pages as a two channel link rather than 8 channel). Also, if the RME were set entirely to SPDIF, it wouldn't sync into the ADAT ports on the expansion board (as they don't do SPDIF) but could sync and send two channels into the DPS24's optical port if that were set to SPDIF. Gotta love digital formats!

The lack of output LEDs on the DPS24 expansion board isn't a good sign though.