Noises on Startup – +48v related

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This topic contains 6 replies, has 6 voices, and was last updated by Profile photo of MJPA Hire MJPA Hire 10 years, 10 months ago.

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    Profile photo of AMURDOCH

    Hi Guys,

    Have installed a GLD-80 in a church with a 24ch & 8ch stagebox.

    Everytime the console is booted up and any master faders left up (including aux’s and matrix’s) we get squealing (almost like feedback) and a big pop on bootup. This is at the end of the console boot sequence as all the channel labels light up and the desk becomes usable.

    I have spent some time finding where the noise comes from and it is all channels with phantom power applied to them. I find it strange that the noises occur at all.

    The noise is loud enough to cause hearing damage / driver failure, I had my ears ringing after it occurred the last time.

    A&H tech support – I know they should turn the faders down every time at the end of use but in a church with volunteers it may not happen all the time! Can we please get a firmware update that mutes the audio until this has passed? I know it will add another 10-15 seconds boot time but I’d rather that over hearing damage or having to replace drivers!

    I have also run one in our rental department for a school musical & ran into the same problem, though I didn’t realise what was causing it at the time!

    Look forward to hearing everyone else’s experience / feedback from tech support.

    Profile photo of eotsskleet

    I’ve never had Problems with that, even a band was having soundcheck (included some microphones with +48V), power dropped out, restart of the desk and back where i was before! No Feedback! Just a little “pop” when connection to the PA was back.

    (P.S. I didn’t update firmware to 1.12 yet!)

    However… 2-3seconds more for boot up with the benefit of having a auto mute on all outputs would be accepted and a nice feature!

    GLD-80 / AR2412 / AR84 / Qu-16

    Profile photo of KB7981

    I don’t know your backgroundbut my first question is are the amps for the system already turned on while the console is booting up? Since I have been working with audio, the amps are usually the last thing to be turned on. I generally power up in an order like the following with or without a power sequencer…

    – Inputs for console ( cordless mic receivers, cd / tape / mini disc players / etc.)
    – Input processors
    – Console and associated stage boxs ( mix racks)
    – Output processors and auxiliary fed equipment (speaker processors, house and monitor EQs and compressors, remote mixers, aviom, hearback, mymix, zone splitters, etc.)
    – Amplifiers, and powered speakers

    Although, I have set up a scene on the iLive we use to mute the outputs and then assigned a softkey to recall that scene. Before shutting the console down, the operator is suppose to press this softkey so that the outputs would be muted when the system is turned on the next time just in case there would be any issues. With the console over 150 feet from the racks, if levels were left up, you wouldn’t be able to get there fast enough to mute the offending item(s) if something were to happen.

    Indiana, USA

    Profile photo of gilparente


    I agree there must be something wrong with the console, but regardless of the console you use, fixing your power up and down sequence should be your main concern. It is the first thing I address in customer training.
    There are many ways of dealing with sequencing if the equipments are on opposing sides of the building or if you are dealing with powered speakers. There are solutions for all of these scenarios. If you dont know how to properly address that, you should contact someone to help you with it.
    Feel free to post your set up here and ill gladly point out what i think would work for your facility.

    Take care

    Gil Parente
    Design & Integration
    Entertainment Arts, Inc.
    iLive 176, T112
    iDR48 , iDR16, iDR10
    Multiple iPads

    Profile photo of AMURDOCH

    Hi Guys,

    Yes there is a sequence where the console boots first and amplifiers on 15 seconds later, I am well aware of the proper on / off procedure. This still does not stop the loud noises that occur 1 minute into the boot sequence.

    Profile photo of Sound Doctor
    Sound Doctor

    Do you mean that the power to the amps starts 15 seconds after power tp the amps?
    If so, you should set the delay until after the GLD fully boots up, say 90 seconds or so. That way there is little chance that the GLD boot up will send a signal to the amps as it boots.

    I do not have an auto boot up power sequencer in my system, so I wait until the GLD and AR2412 are booted up and communicating before I power up the amps. Never have any pops or squealing.

    You are probably getting feedback in the monitors before the end of the GLD boot up can apply the EQ settings to the monitors, etc.


    Profile photo of MJPA Hire
    MJPA Hire

    I had the same issue after losing power supply to my GLD desk during a performance,, on power up with the amps and microphones on I experienced the same issue as you have.
    This forum dismissed this issue as a problem with the desk.


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