Intermittent Loud Pop & Crack sound in DM-4800

[rap121977]

Hi,

I have issue with my DM-4800. When using clock 44.1k and 48k, intermittently loud pop and crack sound came from random channel(s). sometimes come from one sometime several or even all of them. when the pop and crack sound came, the channel signal peak out. it was normal after boot, and after that (it can be minutes after boot), the sound came, but sometimes, they didn't came at all.

however, when I change the clock to 88.2k/96k, no issue.


Any idea what is the issue?

Pardon my english, I hope you get the idea.

 

[captdan]

There's probably some wordclock issue afoot - a mismatch between your DM and the DAW.

What DAW (or recorder) are you using? Firewire or not?

CaptDan

 

[rap121977]

No daw used.

I have an adat mic pre amp that was set as slave.

I once set it as master and dm as slave still the same. Disconect the adat and use the internal clock still have the same issue.

I also suspect the clock just no idea where to look at. Is there somekind reset feature?

Thanks
Robert

 

[captdan]

Are you using the DM as a live desk or are you recording to a hardrive or computer?

In either case, the DM should be set as wordclock master (making sure you're toggled the desired sample rate in the Project/Clock menu.) I'm not sure, but I don't think ADAT carries wordclock by itself (it's been awhile, so I could be wrong.). Is there a BNC/Wordclock input on your ADAT mic pre? You might have to send W/C to the preamp that way.

In the meantime, set the DM as WC master,then reboot it with the pre amp OFF. Then fire up the pre amp and see if that helps.

CaptDan

 

[cmaffia]

I had what sounds like the exact issue with my first DM3200. I wouldn't have anything plugged into it nor would I have a computer on.. completely standalone other than the monitors and headsets. It turned out that the intermittent pops and clicks were spontaneously generating from the EFFECTS returns! Nothing was evening being sent to them but that's where they came from no matter what channels I assigned them too. Like you, the higher the I clocked, the less it occured. You may want to see if this is the same problem I experienced. I wont go into my saga but it ended up only being resolved by replacing the entire unit (which was still under warranty)

 

[rap121977]

If that's the case, is it possible to turn of the effect return? or even the effect engine??

THanks

 

[Will Miho]

You just go to the routing page and change the assignment for the output of the effects to wherever you have them routed.

But you might trying changing the Fx patch first. There are a couple of patches I think that have problems.

 

[cmaffia]

Until I was ready to send in for repair, I would just mute the effect returns.
Some effect patches made the problem less obvious where others such as reverbs with long tails made it worse. Point is, the problem still existed despite my efforts to hide it. I set up my LCD meters to not clear and caught the signal coming in on the default effect returns for EFFECT 2. Nothing resolved the issue (SRAM INIT included), not even Tascam's first attempt to repair it in which they replaced the Main PCB board. After 2 weeks the problem returned. Of course these tips are assuming your problem is the same one I experienced. I also recall that the board would make the popping noises almost 30 seconds after a cold boot and that the frequency would diminish after the board was on for a while. Like you, the higher sampling rates did not seem to have an issue and if I did hear the popping, it was noticeably less frequent.

 

[rap121977]

Hi

I tried to volume down the input and output in the effect and even mute the effect return, it still there. Actually the pop sound is triggered by several channel or sometimes all of them randomly. rebooting usually help to get rid of the issue temporarily. but then, after a while, it returns. sometimes triggered by peaking on one of the channel and like domino effect, other channels start to pop.

is there any other else that I need to look ?

Thanks all.

 

[cmaffia]

At this point if the board is doing this with NOTHING plugged into it... and I mean nothing but the AC cord....no ADAT preamps, no external gear, no anything..and it is initialized to factory defaults, then I'd say you're looking at sending it to Tascam for repair. It obviously isn't suppose to behave this way. Just my opinion. Far from expert with this machine. Maybe someone else has another suggestion.

Other things come to mind.
Could your power source be the cause?
Do you hear these noises with headphones?

 

[Muziekschuur]

I think Cmaffia is the best expert here on this issue. If an amplifier has this issue it's usually broken capacitors... But this is not an amplifier.

Hmmm... I assume a clocking cable between the mixer and the preamp could fix this issue. Because ADAT was not an open protocol for many years. And ADAT is only complete with an ADAT SYNC connection. (9 pin connector). Tascam does not pay any fees to Alesis because they reverse engineered. On earlier cards the ADAT sync connection is shut down... (but present)...

Any issues with clocking were solved with a clocking cable... ADAT usually synces over ADAT optical. But if those settings are not made issues arise. But wordclock supsides everything. So when the system sees wordclock it is what it listens to.

When you have: PC MIXER RACKPREAMP(ADAT) you have a chain wich needs to be setup carefully with a very clear MASTER SLAVE setup.

 

[cmaffia]

Again, the first thing I would do is:

1. Make sure the board is set to factory default,
2. Unplug EVERYTHING from the board except the headphones
3. Watch the meters and listen for the pops and clicks.

If you are still hearing noises when the DM4800 is in pure standalone mode, then call Tascam.

If you don't hear noise when everything is unplugged, then something external is causing the issue. As Muziekschuur has pointed out, an ADAT incompatibility or misconfiguration with your preamps could be one cause.

Also, if you don't hear the noises when everything is unplugged, I strongly suggest plugging in your external equipment one at time to see which device is causing the issue.

 

[cmaffia]

Any updates on this?