Rehearsal Horror-qu-pac died

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This topic contains 12 replies, has 6 voices, and was last updated by Profile photo of Andreas Andreas 3 years, 11 months ago.

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  • #62913
    Profile photo of Mbirame
    Mbirame
    Participant

    Hi guys,
    My three week old qu-pac just shut itself off in the middle of a 3 hour long rehearsal. i was using the qu-pad app from the FOH and in the middle of a song, ipad lost connection and all sound stopped. It took me a second to figure out that the qu-pac was turned off. It was plugged into the same powerstrip as our in-ear transmitters and they still had power. The qu-pac is in a shallow 6U case in the top 4 U and the bottom 2U are the sennheiser in-ear transmitters. The unit would not turn back on. I checked the fuse and it was fine and after a few minutes I was able to turn it back on. I immediately saved the show to a thumb drive.

    Do you guys think it overheated? The front and back panels were off on the case, so there was plenty of ventilation. I don’t thing the sennheisers get terribly hot or anything. This is freaking me out because this would kill a show. This was a “b stock” item that my dealer got for me to save a few bucks (without me knowing until the order came in). Unit looks perfectly new and he said it was probably just used in a trade show or something….

    #62915
    Profile photo of Bear
    Bear
    Participant

    That happen to a friend with Qu-PAC but never came back on , sent it back for warranty repair (power supply).

    #62919
    Profile photo of Dick Rees
    Dick Rees
    Participant

    Do you guys think it overheated?

    Yes.

    #62920
    Profile photo of Andreas
    Andreas
    Moderator

    Probably stupid question: Checked that the power plug is completely seated? Happened to me once on an AR2412, using the fixture since…

    #62926
    Profile photo of Mbirame
    Mbirame
    Participant

    Probably stupid question: Checked that the power plug is completely seated? Happened to me once on an AR2412, using the fixture since…

    I’m pretty certain it was good. I emailed the dealer and I’m going to see if he has more info on this “B stock” situation. Maybe it was the one that Bear’s friend returned-ha!

    I hope it didn’t overheat. It was in an air conditioned room-certainly cooler than a usual venue. Sure it was on for three hours and there was other gear below it in the rack, but it’s not like it was tube gear below it and I don’t see any mention in the literature about being careful about gear below it…This stuff should be built to handle full days at festivals, etc, so I can’t imagine we pushed the temp beyond it’s limits…

    #62943
    Profile photo of Mike C
    Mike C
    Participant

    Even if overheating was not the cause of your problem I would leave at least one open rack space under a rack mounted Qu-Pac. There are vents on the bottom that are directly
    under the power supply.
    I custom built a rack for my Qu-pac with ventilation in mind, under the Qu-Pac I have low speed fan under the power supply vents and to add to the cross ventilation through the air tunnel in the middle I cut round holes about three inches in diameter on each side of the rack.
    The holes also function as handles. The rack travels in a small built to fit foam padded trunk style case. Also in the rack is a wireless mic receiver that serves as stage talk back from my wireless headset mic and or as the wireless receiver when I only need a single wireless mic.
    I’ll try to remember and get a couple pics of it when I have it out in a few days my next job.

    In the utility menu you can monitor the internal temperature.

    #62951
    Profile photo of Mbirame
    Mbirame
    Participant

    There are vents on the bottom that are directly under the power supply.

    I didn’t realize that. I saw the ones on the bottom of the rear but I didn’t know there are also vents on the underside. It’s going to be a tight fit. It’s important to be able to have the in-ear transmitters in the same case so they can stay hooked up to save some set-up time if possible. Maybe I can put the QU-pac on the bottom of the rack and that should leave more space for it. I am using a shallow Gator effects rack.

    In the utility menu you can monitor the internal temperature.

    Thanks for that info. I don’t see it in the literature though I did see in this thread that someone from A&H mentioned that once you get up to 80-85 you could be having problems. http://community.allen-heath.com/forums/topic/temp-of-the-dac-q24

    I’m in Texas and seeing that the specs say to have a max ambient temp of 95F concerns me as we have played gigs when it is hotter than that on a number of occasions.

    #62953
    Profile photo of dpdan
    dpdan
    Participant

    95F?
    are you kidding me? It poops out if it gets hotter than 95?
    That thing would never work outside in the summer months in St. Louis either ;(
    I guess you need to get some more fans for the Qpac. MAN OH MAN ! who knew

    #62956
    Profile photo of Dick Rees
    Dick Rees
    Participant

    The specs in the manuals say 45 degrees Celsius for the Qu-pac and 50 Celsius for the Sennheisers. That onverts to 113 Fehrenheit for the Qu-pC and 122 for the TX units.

    I’d look at adding a small fan in the case at any rate.

    #62961
    Profile photo of Andreas
    Andreas
    Moderator

    At least the manual states 35C/95F for the Qu System, not sure if the specs for the Qu-Pac are that much different. I guess the much more interesting point is the effective airflow around the unit. Packed into a shallow cabinet without airflow any electrical unit will suffer at even lower ambient temperatures.
    The Qu system needs some airflow between back and the vents underneath. If the Qu-Pac is mounted in a shallow case with sides closed and something stopping airflow from the bottom this indeed may be critical. As already mentioned, there is a temperature monitor in home dialog, worth checking from time to time.

    #62963
    Profile photo of Mbirame
    Mbirame
    Participant

    95F?
    are you kidding me? It poops out if it gets hotter than 95?

    I don’t know if it will poop out, but the manual says operating range is 32F-95F. I’m pretty convinced that it didn’t overheat but it may have a fault-who knows maybe that IEC cable wasn’t plugged in all the way. It was in a shallow case with both sides open in an air conditioned studio. I will check the DAC temp at tonights rehearsal.

    #62984
    Profile photo of Mbirame
    Mbirame
    Participant

    We had a two hour rehearsal tonight. I monitored the QU-PAC throughout the night and the DAC temp slowly rose and got to 69C. For this rehearsal we did NOT have the Sennheisers turned on so they were not adding ambient heat, but they were still under the QU-PAC. After rehearsal I did go ahead and switch the orientation so the QU-PAC will be on the bottom of the rack. That should give another 1/4″ or so of space to that bottom vent. Also, I’m sure that not having the potentially hot sennheisers right by that vent will be helpful. I’ll continue to monitor, but I certainly hope this doesn’t become an issue because the conditions in the rehearsal room are about as good as they will ever be. It would be nice to not have to hack a hole in to this brand new Gator effects rack.

    #62992
    Profile photo of Andreas
    Andreas
    Moderator

    If it really should be a temperature issue, I don’t think it is necessary to drill a hole into your case. When I used an external rack with three 8ch DACs for recording, the units also failed due to temperature (that was a temperature issue). I’ve just mounted a slim, slow rotating fan at one side which enforced a slight air flow through the devices and issue was gone.
    That should work for the Qu-Pac even better since it does have a large “hole” in its shape to guide the airflow.
    For my Qu32 I’ve mounted slow fans underneath the mixer to enforce a little airflow, since the backside is closed with a dog-box, effectively disabling any kind of voluntary air-flow. Never had an issue before, but I’m little paranoid regarding temperature… 😉

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