d8b Forum

Good Morning All,
Ive come across a strange experience yesterday afternoon, that has kinda shut me down for recording.

When doing digital line in recording on any of the first 8 channels, I get a "noise", that automatically sends intermittent noise/signals to any of the first 8 tracks I have set in record mode on the recorder (and also showing on channels 25-32 on the d8b).

Ive tried a bunch of testing, and am still coming up with the same issue. I was hoping maybe someone here might have gone thru something like this before, and had a possible fix/repair.
What I have tried so far...

1) This "noise' on the recorder happens even when no signal is being sent into the d8b (guitar/mic , etc) and then to the recorder from the d8b. As long as the recorder is in the "loop", the recorder gets noise when hooked to the lightpipe.

2) To see if this was an issue with d8b or the recorder, I powered down, disconnected the lightpipes, powered up the recorder, put the first 8 channels in record mode, All looked good. Where this noise issue doesnt happen when the lightpipes arent connected, I thought it could be a faulty lightpipe. I switched out the IN and OUT on the first 8 going from the d8b to the recorder. Power everything back up again with different lightpipe cable. When setting the recorder to record on any of the tracks from 1 thru 8, still has digital noise coming in on channels 1/8 of the recorder, also showing as playback, on 25 thru 32 of the d8b.

3) Where it didnt seem to be the recorder or the lightipipe, I thought it could be an input card in the d8b that has gone bad. There are 3 OPT8 cards installed. I took the suspected one out, set it aside, and took the card the was for channels 9-16 out and placed in into the slot for 1-8. Powering everything back up again, still the same issue. So to be 100% sure I tried the same concept with the last OPT8 card that would normally be for 17-24, put that in 1-8, powered all back up again, still same issue when placing the recorder in record mode for channels 1-8. I then powered back down, and placed the other 2 cards back into the system. All 3 cards worked correctly in the 9-16 slot or the 17-24 slot, but all of them had issues when in the 1-8 slot on the d8b board.

4) As a side test, I tried switching the lightpipe signals from the d8b (1-8) to the recorders (9-16) and put the d8b (9-16) in the recorder (1-8), swapping the input. Then, the issue of the digital noise coming in was no longer channels 1-8 anymore. Now they were showing on 9-16... Again, this was a test going to and coming d8b 1-8 to recorder 9-16.
Where its not looking like a lightpipe or a card issue, its looking very much like a board issue here.

5) Thinking its a board issue, the only thing Im aware of to do with the board, is to take out the CMOS battery. I did that last night, and let the charge dissipate, and replace with a new CMOS battery this morning. After doing so, while powering up, I reset the CMOS settings to the correct setting for the board I have, that I got from the D8B FAQ page.

Hoping for the best with a new CMOS battery, after powering up with the needed CMOS settings, I put the recorder in record enable mode for the first 8 channels.. and am still getting the original issue... digital noise, popping/crackling on any of those first 8 that are record enabled. Im not sure if it matters or not, but channel one shows a stronger noise issue then the other 7 but they are still present on all 8.

6) As a last test, I took the recorder to friends recording setup, also with a d8b, and all worked correctly on his setup, no noise issues at all.... Bringing the recorder back, and setting back up, same issues...

So, after testing, it
Doesnt seem to be the lightpipe... changing out, same issue.
Doesnt seem to be the OPT8 card(s), swapping them out... same issue.
Swapping lightpipes on the recorder 1-8 for 9-16, then the issue changed to 9-16...
So this shows that while its not the card in the first slot, its something to do with the first slot? maybe?!?

After reading this, might anyone have some insite for me? Im kinda shut down till I can get this working again.

Popping and clicking is usually associated with a clocking issue of some sort. How are you clocking all of these digital animals together?

Is it the Apogee clock card you are speaking of? If thats it, then yes, Im using an Apogee clock card. Is there a way that I can test that to see if things are working correctly?

the Apogee clock in within the d8b

What s the master clock in your set up? You can look at the vacuum display and see if you see an alternating * and ? which would indicate a loss of clock signal.

I have the d8b as the master clock. When playing a recording, Im not seeing an alternating * or ?. Is there anything else I could look for. Looking that Mackie website, is speaks of the DSP board needing to be looked at by a service tech. any thoughts to that?

What is the *recorder* clocking to? If it's the lightpipe signal, make sure it's clocking to that and not to its internal clock.

The recorder is a Mackie HDR. It was set accordingly before, but I did just check again to be sure that clock was set correctly. I havent changed any of the wiring or settings until this incident happened. For the last 18 months, all had been working as it should. Yesterday this started happening.

I assume you are clocking via BNC cable, have you tried a new/different one? The oddity in this is that you say it is just the first 8 channels which has me perplexed. Have you considered doing the internal ribbon cable reseat procedure?

I have tried a new BNC, but still same issue. The first 8 channels, yes.. thats what made me think it was possibly one of the OPT8 cards gone bad. Whichever card on the HDR that I plug in from the first port on the d8b, I get this issue. Im perplexed as well.