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mkh 50 and zaxcom trx 742 problem


Jatb51

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Hello, I'm using the zaxcom Trx 742 for boom tx, I prefer to have the transmitter mounted by the top of the pole - when mounted with 416 we have no issues, clean, when mounted with mkh50 we are getting rf interference - see attached .wav file - (mkh 50's  have been rf shielded by sennheiser). Tried

mounting 50 at bottom of the pole - same problem. Wondering if this a wiring/grounding issue with the xlr. Boom pole is internally cabled - perhaps the coil is effecting it? Has anyone experienced this - any luck with Neutrik dmc series xlr connections?

Thanks is advance

James

1A-001a.wav

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I use Neutrik EMC connectors all the time now - excellent.

I'm not sure what the Zaxcom is like for spurious emissions.  Is it the USA version of the Zaxcom you are using, or the international version?  The US version had a very wide window compared to the international version (though it was a few years ago when I saw these radiation graphs).

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1 hour ago, John Willett said:

I use Neutrik EMC connectors all the time now - excellent.

I'm not sure what the Zaxcom is like for spurious emissions.  Is it the USA version of the Zaxcom you are using, or the international version?  The US version had a very wide window compared to the international version (though it was a few years ago when I saw these radiation graphs).

Zaxcom have EU mode (125kHz) and US mode (200kHz) in preferences

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I've run into rf issue's with various connectors and the 742. I had to return 2 K-Tek plug on mounts because both of them induced rf when the 742 was used. No problem when connected directly to the pole base. Just ran into the same issue when using a short mogami cable and the 742 a few days ago as well. 

 

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17 hours ago, Jatb51 said:

 

Hello, I'm using the zaxcom Trx 742 for boom tx, I prefer to have the transmitter mounted by the top of the pole - when mounted with 416 we have no issues, clean, when mounted with mkh50 we are getting rf interference - see attached .wav file - (mkh 50's  have been rf shielded by sennheiser). Tried

mounting 50 at bottom of the pole - same problem. Wondering if this a wiring/grounding issue with the xlr. Boom pole is internally cabled - perhaps the coil is effecting it? Has anyone experienced this - any luck with Neutrik dmc series xlr connections?

Thanks is advance

James

1A-001a.wav

 

Hi James I just listened to the file and its exactly what I  get on both my 742 and 942 with a MKH 60, 50 or 40. My schoeps are all good so i have resorted to using these which i prefer anyway but it is a concern. I sent my 942 back to zaxcom last year to fix this and it was better for a while but now does it. Is it because my sennheisers are about 15 years old and don't have the same RF rejection that more modern mics have? or is it a zaxcom thing? I also have an Areitec pico48 which i run with a TRX900 as a third wireless boom so maybe i will test that with the sennheisers and then we can eliminate either the transmitter or 48v power supply.

Regards

Tony

 

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"Is it because my sennheisers are about 15 years old and don't have the same RF rejection that more modern mics have?" 

I think this is probably the answer. The older designs did not have to contend with the RF problems we have today, and of course there was none of the digital RF issues which many of the microphones had until the manufacturers did re-designs to solve this.

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6 hours ago, Jeff Wexler said:

 The older designs did not have to contend with the RF problems we have today, and of course there was none of the digital RF issues which many of the microphones had until the manufacturers did re-designs to solve this.

Does anyone know if you can get your existing sennheisers modified with better RF rejection as opposed to buying new ones, or if in fact the new ones still have this problem with the zax gear. Or does Zaxcom have a fix for this?

its at the stage for me of either selling my sennheisers or not using them. 

Tony

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36 minutes ago, ProSound said:

Yes if you have silver pins it hasn't been updated you can call with Serial number to to confirm if yours needs an update they are very helpful 

Yep mine have silver pins. So can they be sent back and upgraded? Has anyone done this? Cost etc.

tony

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  • 2 years later...
On 3/5/2016 at 8:05 AM, John Willett said:

I use Neutrik EMC connectors all the time now - excellent.

I'm not sure what the Zaxcom is like for spurious emissions.  Is it the USA version of the Zaxcom you are using, or the international version?  The US version had a very wide window compared to the international version (though it was a few years ago when I saw these radiation graphs).

agreed, when I use my TRX900 w STA100 for hops in BLK20 I get a layer of interference on my BLK 22 lectro RXs... weird. 

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