humming when ada8000 is connected to Pulsar 2

helldriver · Post by **helldriver** » Sat Jul 23, 2005 7:41 am

can somebody help me?
i have a serious problem.
i bought me a behringer ada8000 adat interface to expand my physical audioinputs of my pulsar 2.
but somthing is going wrong.
when the ada is connected to pulsar, i get noise (humming). the input is working but because of the humming not usable. the humming is over when i switch off the ada 8000.
had somebody the same experience?
i´m totally confused by this because i thought adat connections cannot cause humming. it must be the ada 8000.

Post by **hubird** » Sat Jul 23, 2005 8:00 am

you must have a groundloop, or experience magnetic interference from other machines.
check or experiment with your ground setup and or physical placing of the box

astroman · Post by **astroman** » Sat Jul 23, 2005 8:12 am

if this appears with nothing connected to the inputs then just use another powersupply for the converter - some wallwarts aren't up to their specs.

cheers, Tom

Post by **garyb** » Sat Jul 23, 2005 8:48 am

the ada8000 is a great unit(it has no wall wart), but it is very sensitive to grounding issues. you have a ground loop. most likely, it is between the ada8000 and whatever is plugged into it. it may help to plug both the ada8000 and the offending item into the same outlet(you may need an extension cord) or to lift ground on the device connected to the input or output(speakers, or amp?). it is unlikely that the ada8000 and scope are the culprit together, since they're connected by light and a plastic cable.

if you have nothing else connected to the behringer and it's noisy, then it's most likely broken. if i were to guess at the cause, it'd be broken solder connection either in the power supply or to ground.

oh yes,
don't forget that a bad cable will be noisy as well(not light pipe. a bad lightpipe cable just won't work)....

<font size=-1>[ This Message was edited by: garyb on 2005-07-23 09:52 ]</font>

astroman · Post by **astroman** » Sat Jul 23, 2005 10:04 am

On 2005-07-23 09:48, garyb wrote:
the ada8000 is a great unit(it has no wall wart), ...

respect - I wouldn't have expected that...

helldriver · Post by **helldriver** » Sat Jul 23, 2005 10:45 am

hi
thanks for the replys,
but the ada 8000 is humming.
he is humming although no instrument is connected to it. the more channels are on, the more he is humming.
if i connect a insrument to it, the humming get even louder.
the humming should not be caused by my rack devices (line6 delay modeler, mindprint envoice) i guess.
so what can i do?
it´s a brand new unit
shall i bring ist back to the shop, shall i buy me a professional cable socket for the power supply?

astroman · Post by **astroman** » Sat Jul 23, 2005 11:33 am

as GaryB wrote, it's most likely broken, a bad solder joint, damaged cap or whatever - since it's brand new, this should be no problem for your shop to replace it.

cheers, Tom

Stige · Post by **Stige** » Tue Jul 26, 2005 6:17 am

Here at the local studio is just similar case. I believe there is a bad batch being sold.

Shroomz~> · Post by **Shroomz~>** » Tue Jul 26, 2005 7:26 am

Hi Helldriver,

It definately sounds like a grounding issue as mentioned in other replies above. If your getting humming with no equipment hooked up to the analogue inputs of the Behringer, which goes away on powering it off, you've partially tracked the problem.

Something which is worth a mention are ground terminals. We don't have this unit so i don't know if it has one or not, but some equipment comes with a 'grounding terminal'. If properly set up, this should be directly connected to a 'mains' ground terminal (or a studio encompassing loop if you have several such instruments)IE get some well insulated elctrical ground wire or 3-core if you have some lying around & connect this terminal (if it has one) directly to the ground/earth connector in a mains plug point or multiway. If the unit doesn't have this terminal & is under warranty, take it back for repair or replacement. It might be just a loose wire or something like Garyb suggested, but it's not worth the risk of opening it if you can have it replaced or repaired under warranty. If you're not confident, take it back.

I heard customer feedback reports by Sound Control staff in the UK about 2 years ago that Behringers 4 or 8 channel DI boxes had grounding issues reminiscent of radio reception