• Registered: 2014-05-23
  • Posts: 7

Topic: Phantom 48v problem on UCX

There seems to be a problem with my UCX interface.
I have been using a Rode Nta1 condenser microphone for a couple of years with great results.
Last week I was setting up an overdub session and when I switched the 48v power on input 1, the channel has a base noise like a hum. I got scared so I tried the same config on channel 2 and the same noise was present.
Then I tried both preamps with a dynamic mic (sm58) and the both worked fine.
I thought it was a problem with the nta1 and send it to the technical service. They reported that the mic is in perfect condition.

Any ideas??

  • Registered: 2014-05-23
  • Posts: 7

Re: Phantom 48v problem on UCX

Bump

  • Jeff
  • Jeff
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  • From: USA
  • Registered: 2007-05-21
  • Posts: 4,650

Re: Phantom 48v problem on UCX

Any chance to check a different mic that requires Phantom power? It's possible that the input on the UCX is damaged, but unlikely that both mic inputs are broken.

Regards,
Jeff Petersen
Synthax Inc.

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  • Registered: 2012-04-15
  • Posts: 90

Re: Phantom 48v problem on UCX

It's possible there's a problem with the 48V supply.  (maybe shorted regulator or open cap)

You can check it with a simple DC voltmeter.  You should show 48V between pin 2 and pin 1 as well as 48V between pin 3 and pin 1.

  • Registered: 2014-05-23
  • Posts: 7

Re: Phantom 48v problem on UCX

boz6906 wrote:

It's possible there's a problem with the 48V supply.  (maybe shorted regulator or open cap)

You can check it with a simple DC voltmeter.  You should show 48V between pin 2 and pin 1 as well as 48V between pin 3 and pin 1.

It shows 50V on both preamps...

  • cyrano
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  • From: Belgium
  • Registered: 2015-04-28
  • Posts: 701

Re: Phantom 48v problem on UCX

alejandrozalaquett wrote:

It shows 50V on both preamps...

That's within specs. The standard allows up to 54V.

I don't think the NT1a is very power hungry. That said, mics can change current draw over time. I have one old mic that refuses duty on anything USB-bus powered. Works fine with a FF400 on firewire bus power.

That mic has a lot of different behaviours depending on the interface's phantom power. I've heard it motorboating, dropping out every minute, crackling... No hum tho.

So you really need to test that NT1a on another device, if possible and another phantom powered mic to test the UCX.

I wonder how they tested that NT1a of yours. Think they measured current consumption?
And, out of curiousity, how old is that NT1a?

MB Pro - 2 X FireFace 400, FF800 & DigiFace USB
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