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QRX200 internal PSU introduces noise


Matthias Richter
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I´ve got a brand new QRX200 which gives me hard time. It injects some "fieping" noise into my system.

 

Using the analog output here.

It is the worst when I try to get both TRX on one TA5. The right output on both TA5 basically are not usable. Using TRX1 on output 1 (pin 1,2,3) and TRX2 on output 2 (pin 1,2,3) is a lot better but still audible.

 

Got a replacement from Zaxcom - same noise.

 

We (Kortwich and I) tried every kind of testing to no avail. Even powered the QRX200 of a different power source than the rest.

 

My QRX100 is clean and a tested QRX235 was clean too.

 

Could you guys with a QRX200 have a good listen to your analog outputs please to see if that is on every QRX200 out there?

 

Thanks, Matthias

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I had the same problem, where my 4 QRXs introduced a low-level high pitched whine into my Sonosax mixer, not unlike what an IFB100 used to produce when on the same power supply.  I believe at one point I even had the grounds (pin1) disconnected entirely, and this removed all of the noise, however this may have been specific for my cart/setup, and maybe not a very safe solution, for the equipment.

I recently switched to an RX12, and have since had zero problems (pin1 connected).

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  • 3 weeks later...

What are you feeding into what?

Turn off and disconnect everything except what you need to test. Put the QRX200 on its own battery supply and the mixer (Nomad?) on another.

Is the noise still there? If not, it does sound like the problem lies somewhere within power and grounding.

Not a new issue with gear -- figuring out power supply and grounding issues have been with us since man first tamed electrons in the wild.

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I had a experience with QRX 100 causing Noise. I don't know why, but every time when the LED on QRX 100 twinkled red, i get a "bip" impulse noise on my both analoge wireless channels. This happens even when the analoge wireless turned off. (QRX goes AES into Nomad and Analoge Wireless uses Analoge 3&4)..

 

p.s. It would be nice if Zaxcom can open a service office in Europe, because shipping to the US is really a pain..

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I had a experience with QRX 100 causing Noise. I don't know why, but every time when the LED on QRX 100 twinkled red, i get a "bip" impulse noise on my both analoge wireless channels. This happens even when the analoge wireless turned off. (QRX goes AES into Nomad and Analoge Wireless uses Analoge 3&4)..

p.s. It would be nice if Zaxcom can open a service office in Europe, because shipping to the US is really a pain..

Everything Audio in Elstree survive zaxcom.
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  • 2 years later...
On 19.4.2015 at 10:49 AM, Matthias Richter said:

so I'm not alone. Is this good or bad? ;)

 

Tested the new cable. Still that whine. Analog out 3+4 (right ch on both TA5) are noisy.

 

Sorry for bringing up this old topic, but I am currently considering to buy a QRX200. 

Matthias, have you been able to resolve this issue? If so, how?

 

Thanks...

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19 hours ago, Matthias Richter said:

using the regulated 12V from an Audioroot and using the 2 TA5 for 2 TRXs is ok under most circumstances. Thats what I still do ... Using it for radio mics (lavs) only though.

 

Thanks ok. So it sounds like you are still not entirely happy about it, but managed to work around it

 

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50 minutes ago, Matthias Richter said:

And I can´t fight every single issue to death. Your choise ;-)

 

Sure thing. Noise induced by Zaxcom gear is not a new issue, but I am surprised why they can't get it sorted on their end, but maybe also it was just your particular unit. 

I'll be using it as my boom mic rx so I'll be very picky and I suspect that any issue - should there be one - will reveal itself, so I am hoping it was just your unit. 

So I took a chance and have just ordered one. 

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Almost everything these days has 1 or more switching power supplies inside. If the frequency of a power supply (1 to 2 MHz) is too close to other devices that also have switching power supplies they can mix together and the sums and differences can fall into the audio pass band and can become a problem. I am sure this can be solved with a DC power filter or some other minor bag configuration change. I am available at the office to help over the phone.

 

Glenn 

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