mghough

DPA RFI Problem

19 posts in this topic

I purchased the DPA4017b set from B&H about 7 months ago.  I love the mic but after 4-5 months I started having serious RFI problems with my TX742. (See Video) Does anyone know how to solve this?  I've spoke to DPA and they say that I need to send in the preamp so they can evaluate it.  I'm living in Mainland China so sending anything out of the country or receiving anything from out of the country is a problem.  I previously used a RODE NTG3 for years without a problem.  I really expected more from a mic that cost more than $2000!!!

 

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disconnect the connection in the female XLR between pin 1 and the shell.

done that to my suspensions and have no issues with my 4017B in a cinela mount, or my 4011C in a rycote invision with custom low profile XLR.

if you plug the 742 straight into the mic, and you have RFI, then you need to get hold of another 742 and 4017B so you can swap thing sover to see where the problem is.

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Similar to Rich, I was going to suggest putting an XLR cable with and then without a grounded shell between TRX and O/P stage, at least to see what happens.

I was also curious to know what happens with your 4018 + mmpB + TRX742.

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Maybe the DPA 4017B is the older version. I had problems in the other day with an older version of DPA 4017B; cable to SQN.

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4 hours ago, rich said:

disconnect the connection in the female XLR between pin 1 and the shell.

done that to my suspensions and have no issues with my 4017B in a cinela mount, or my 4011C in a rycote invision with custom low profile XLR.

if you plug the 742 straight into the mic, and you have RFI, then you need to get hold of another 742 and 4017B so you can swap thing sover to see where the problem is.

742 direct into the mic is better.  also using another mount where the cable doesn't encircle the preamp is fine.  I like that mount and that preamp (if working properly) shouldn't have this issue.  I could change mounts but would rather not.  I may try the pin disconnect idea. :)

3 hours ago, daniel said:

Similar to Rich, I was going to suggest putting an XLR cable with and then without a grounded shell between TRX and O/P stage, at least to see what happens.

I was also curious to know what happens with your 4018 + mmpB + TRX742.

4018 with the MMPb has the same noise issue just thought that would be redundant to show in the video.  

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hmm.

will double check my 4017B with the 742 straight into it, but i dont remember any problems. and certainly have had no issues with it in use.

i remember that the MK1 4017 had RFI issues, but the MK2 was supposed to have cured that. but i think that you, the same as me have the modular system, which for me has been noise free.

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I had the same problem and connected pin 1 to the shell on both ends and the problem went away. I was using a Neumann KMR81 though, and I connect up next to the mic to add to Rado's question, if it matters....

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Have been hunting around for more threads on RFI in DPA 4017/18 MMP-B + MMP-C pre-amp.. haven't found much here. A fellow mixer and I just purchased a couple of 4018 capsules with MMP-C pre amps and the pre amps seem to be inducing a kind of steady, airy, fan like RFI when used with a lectro HMa. Works fine when wired directly, tested with a third 4018 w MMP-C pre amp of an older vintage, which seems to work fine with an HMA. Wonder if the pin disconnection idea is the solution? Any one else having trouble with MMP-C over wireless?

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Very curious, I have 3x 4018 with C preamp and a two 4017 with B preamp and at the moment none of them have any noise with my TX743 or TRX700

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I've run into this off and on with my 4017b and 742. It really seems to be a cable/ground issue. When plugged into the base of any of my K-Tek poles its just fine. However, I bought 2 of their right angle plug on holders and both had the rfi issue. I also had the 4017b connected to the 742 via a short Mogami xlr once and instant rfi. Cable was fine otherwise.

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So far I've had few problems with both the B and C amps. I bought the C amp quite recently, so maybe the issues still arise.
I have both a 742 and a Lectro UH400a. Both are fine. But I have also just bought a Rycote Tac!t cable for the Cyclone and this is all but unusable. On a long boom, my boom op wears the tx on his belt, so really far away from the mic, but still audible interference. The tx on the mic end of the pole is a no in this case. Without the Tac!t it's fine, though.

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1 hour ago, Constantin said:

So far I've had few problems with both the B and C amps. I bought the C amp quite recently, so maybe the issues still arise.
I have both a 742 and a Lectro UH400a. Both are fine. But I have also just bought a Rycote Tac!t cable for the Cyclone and this is all but unusable. On a long boom, my boom op wears the tx on his belt, so really far away from the mic, but still audible interference. The tx on the mic end of the pole is a no in this case. Without the Tac!t it's fine, though.

Hi i found that tac!t cable anwhere near a zax tx would make it unuseable also found the tac!t would pick up bad rf from mobiles etc in doc setup

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I have 2 x 4017b and use them with zax 742.5 and a 743.5, first time with both the one with 742 gave me RF int, swapped mics over and then they were clean on both TRX's. Random and haven't tested further yet as they been ok.

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Reading the topic I got paranoid and tested my dpa4017 with the c preamp and TRX 742.5 Put it in the dishwasher to get as quiet as possible ( only quietest spot in apartment, it was the dishwasher or the oven) and didn't hear any RFI. Will try with the b preamp but lately have been using the c all the time. 

20170405_110134_HDR.jpg

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Reading the topic I got paranoid and tested my dpa4017 with the c preamp and TRX 742.5 Put it in the dishwasher to get as quiet as possible ( only quietest spot in apartment, it was the dishwasher or the oven) and didn't hear any RFI. Will try with the b preamp but lately have been using the c all the time. 
20170405_110134_HDR.thumb.jpg.572a997e60f381d955d92056d34a3530.jpg

No need to get paranoid for anyone, just with the Tac!t

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Also using the dpa 4017c on a rycote Inv 3 with the dpa light weight XLR jumper cable yelds no RFI issues. Pin 1 is not grounded to shell in the male XLR.

 

 

Side question Is there a way to open up safely the dpa XLR female connector?

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I just bought a couple of Tacit cables and they are no good with my HMa/8060 combo. Sounds fine when hardwired, but through the HMa I get what sounds like a loose cable crackle and occasional low freq rumble.

I Haven't tried it with my dpa 4017b and i don't think I will bother.

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Give it a try. You never know what might happen. 

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