Phantom + pad = pops

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This topic contains 9 replies, has 6 voices, and was last updated by Profile photo of Mr-B Mr-B 8 years, 8 months ago.

Viewing 10 posts - 1 through 10 (of 10 total)
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  • #23335
    Profile photo of Forteutrustning
    Forteutrustning
    Participant

    Hi!

    Using a iDR32 and a T112/Mixpad we had a problem during a show where the noise level were really high for all channels and when changing gain on the channel i would get a pop every time the table switched LEDs (those who represent the gain level), this was also still left when i plugged out the table and just ran the mixpad app. Anyone had any problems with this?

    I wasn’t able to reproduce this error today when i tried but i did find one thing. When applying phantom to a channel i get a pop as usual but then when padding on/off i also start getting pops. Then when i switch the phantom off i still get pops from padding but after a while they stop. I guess this could have something to do with the condenser that take a while to charge out and thus leave the pops a while after. Correct?

    Also when driving the gain hard i ofcourse get a high noise level but when i pad the channel i still get the same noise level. Since I’m hearing a little click from the iDR32 (from the box, not through the PA) I guess it’s a mechanical switch that switches on the pad. Is this correct?

    All the testing I did today was without anything plugged in on the inputs of theese channels. Is this wrong? Should I have something plugged in when testing this?

    #31623
    Profile photo of SteffenR
    SteffenR
    Participant

    quote:


    Originally posted by Forteutrustning

    Hi!

    Using a iDR32 and a T112/Mixpad we had a problem during a show where the noise level were really high for all channels and when changing gain on the channel i would get a pop every time the table switched LEDs (those who represent the gain level), this was also still left when i plugged out the table and just ran the mixpad app. Anyone had any problems with this?

    I wasn’t able to reproduce this error today when i tried but i did find one thing. When applying phantom to a channel i get a pop as usual but then when padding on/off i also start getting pops. Then when i switch the phantom off i still get pops from padding but after a while they stop. I guess this could have something to do with the condenser that take a while to charge out and thus leave the pops a while after. Correct?


    That’s right, condenser mics need some time to “uncharge”

    quote:


    Also when driving the gain hard i ofcourse get a high noise level but when i pad the channel i still get the same noise level. Since I’m hearing a little click from the iDR32 (from the box, not through the PA) I guess it’s a mechanical switch that switches on the pad. Is this correct?


    Yes, it’s mechanical

    quote:


    All the testing I did today was without anything plugged in on the inputs of theese channels. Is this wrong? Should I have something plugged in when testing this?


    SRV-AVB
    R-72, iDR-16, xDR-16, Dante

    #31690
    Profile photo of zblebt
    zblebt
    Participant

    From what I know, you shouldnt be changing gain with fader up. you will hear a popping sound on whatever console, analog or digital, no matter if it’s +48 or not, condenser or dynamic, this is just because of the operational amplifiers.

    iDR 48
    T112
    waiting for iPad2 and M-Dante… blindly….

    #31692
    Profile photo of SteffenR
    SteffenR
    Participant

    that’s not correct…

    SRV-AVB
    R-72, iDR-16, xDR-16, Dante

    #31693
    Profile photo of Mr-B
    Mr-B
    Participant

    If I remember correctly the gain control on an iLive is a series of fixed value attenuators set at half dB increments which is why you hear the pop or click when you move the gain control, the pad switch is a mechanical one using a relay. The pad is positioned before the gain stage so the level is attenuated before the signal enters so as not to overload the input amplifier, the noise figure of the amplifier remains the same whether the pad is used or not because it is the self noise of the circuit and not a function of the pad. I am sure if I have it wrong some one will correct me.
    Ian B.

    #31729
    Profile photo of Forteutrustning
    Forteutrustning
    Participant

    Thank you for the responses it seems that the iDR32 now has sorted itself out and is not making any extra noise now. The fault was probably something electrical or some bad XLR’s or something (thought i checked everything but you never know)

    On another topic i wondered if you run the table on the same power as the monitors/PA (as you would normally do) or give it whatever is closest. The real question is have you ever had any ground problems with the table since it runs on a ethernet cable? (noise from not matching grounds)

    #31730
    Profile photo of zblebt
    zblebt
    Participant

    No problems ever. We kinda always use a different outlet.

    iDR 48
    T112
    iPad3 + TL-WDR4300
    waiting for M-Dante… blindly….

    #31733
    Profile photo of teknik99
    teknik99
    Participant

    We always power off a common star point.

    To not do so just invites the looming disaster of earth loop hum which can ruin any show.

    Cheers

    #31739
    Profile photo of jimvoyager
    jimvoyager
    Participant

    In theory it should not matter where you plug the surface in to the power.
    However, I recently did a show where I set up the band monitors with the control surface next to the stage (r72 surface) and then when i was ready, moved it to the back of the hall using a local power point.
    Even before the console was powered up I had the ‘buzz from hell’ over front of house and monitors!
    As soon as the ace link cable touched the r72 in any way I had buzz.
    My feeling is it was seriously bad power at that power point. I tried another only a few meters away and all was fine.
    Jim

    R72 & IDR32
    MacBook pro
    iPad 2
    Airport express router

    #31744
    Profile photo of Mr-B
    Mr-B
    Participant

    I use Fibre, what are earth loops[:D]

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