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Recommended cable length for DPA 130v cables Condenser Microphones
Old 18th July 2005
  #1
Question Recommended cable length for DPA 130v cables

I would like to know what the max cable length is for dpa 130v with a millennia preamp.
I am wondering if it is a bad idea to have a snake made? How much noise will it add?
The main application is classical.
I could easily have use for 90ft, but I am unsure if it is smart to go beyond 50'
Does Millennia make custom snakes for 130v cables?

Kjetil Laukholm

edit:
since then we have used 65' cables with no problem.
Old 18th July 2005
  #2
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nosebleedaudio's Avatar
 

If it was me I would put the pre as close as possible, 20 to 30 feet for example and run it line level as long as it has to be. At least that will give you the least amount of noise. The obvious problem with this is you may not have quick access to the Pre Amp gain pots.
Old 18th July 2005
  #3
I will always use short cables when possible, but I have problems with recording live symphony concerts where the controlroom is far away and the distance for the main hung mics is ..well .. a problem.
I currently have to mount the pre on the catwalk, but I would like to avoid it if it does not have sonic penalties.
Kjetil
Old 21st July 2005
  #4
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Hi Kjetil,

We use the 4003 +130 volt omnis on location in concert halls all the time with Millennia preamps. We have 4 cable lengths - 25, 50, 55, and 85. These are all cables made by Millennia. 99% of the time we use the 50 and 55 lengths. We have used the 85s in cases where it was unavoidable without problem. We have found that the 4003s are much more susceptible to RF interference than the 4006s but it has only been an issue a handful of times over the years. We find that the 50s allow us to get the preamps to the edge of most stages and then we use a high quality snake to get the line level signals back to the control room (usually less than another 75 feet).

Best,
Silas
Old 21st July 2005
  #5
Thank you for your answer - that helps a lot!
Old 30th July 2005
  #6
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sonare's Avatar
This from DPA on cable length:

"Our recommended distance between 4003 and the HMA4000 or equivalent, is
20 meters, however, the ability to be able to handle long cable lengths
is depending on the Max SPL.. If it is below 120dB then 100 m is ok."

A little-known fact is the the signal from the mic to the pre is not balanced. at least not with the HVA4000-5000, therefore the danger of RFI with longer cables from mic to PS.

The PS on the catwalk is never fun to deal with, but the increased signal quality of running line level instead of mic level a few hundred feet is not subtle.

Rich
Old 16th July 2007
  #7
Gear nut
 

Hi all,

I hate raising the dead, but I cannot seem to get a clear-cut answer that I understand, from either Millennia or DPA on this:

If I need to make a cable for use between my DPA 4012 microphones and my Millennia HV-3D preamp with 130V options, and I want to use a balanced mic cable (yes, i know the mic is unbalanced) and two 4-pin XLR ends, exactly what connects to what?

I was told by Joel at Millennia Media that Pin 1 = ground, Pin 2 = no connection, Pin 3 = +130VDC, Pin 4 = unbalanced audio.

...but what is still not clear is whether the shell tab should be tied/connected to anything. Either I don't know how to ask questions, or I'm just not understanding the answers I received from Joel. Maybe someone here could tell me how this cable should be wired?

I called Bruce at DPA, and he said his engineers are on vacation for several weels in the Netherlands. I'd like to be able to use my mics with the Millennia befor then, if possible.
Old 16th July 2007
  #8
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sonare's Avatar
I have never connected the shell and have never had problems with the cables I made for my 4003s.

Rich
Old 16th July 2007
  #9
Gear nut
 

Thanks Rich. I assume you use them with the Millennia?

Anyone else?

(the reason why I'm unsure is that the cables I've seen had the ground and shell tab connected, but they were for a B&K 130V with a custom 130V power supply made by Jim Williams, not the Millennia)
Old 16th July 2007
  #10
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A while ago I resoldered 2 channels of my millenia HV3d to have the special 7 pin connector used on the HMA5000. My thinking was that it would help not needing different sets of cables. Lots of trouble with mains hum (ground loop or whatever). Looking inside the DPA supplied cable I find the shell connected, despite described differently in the DPA broschure. Snipped the connecting off, leaving the shell floating, no problems at all afterwards.

My conclusion is to leave the shell unconnected, something I now has as an habit for all my microphone cables. No problems so far.

Gunnar
Old 17th July 2007
  #11
XLR
Gear Maniac
4 pin XLR

Mitch,

My cables are soldered like in Your description, with no shell connection, and I have no problems with DPA 4003 and Millennia pre.

And cables around 45 ft seem to be ok for me.
Old 17th July 2007
  #12
What to do with the connector shell is a question that isn't limited to unbalanced DPA mics. But unbalanced cable runs are especially susceptable to induced noise. Generally speaking I don't connect the cable shell, because when it's connected, it can very easily cause ground loops when it comes in contact with other metalic things. But that leaves some unshielded wires on the back of the connector. In a very RF-rich environment, connecting the shell would provide additional shielding.

There's an intermediate choice: Connect the shell to pin 1 through a small high-frequency capacitor of 100-200 pF. That keeps the RF shielding intact, without providing a path for 50-60 Hz ground loops. With the increased use of GSM phones and pocket email devices, I'll probably do this the next time I make cables.

David L. Rick
Seventh String Recording
Old 17th July 2007
  #13
Gear nut
 

I don't know much about particular capacitors, so if you happen to know of one with a 100-200 pF capacitance that you would recommend for making cables for my DPA, that would be wonderful. I still haven't made the cables yet.

Thanks for your post. I think I've seen exactly what you're talking about in an old cable for my B&K preamp and 4003, which I bought second-hand. I'll go check and post later tomorrow.
Old 17th July 2007
  #14
Quote:
Originally Posted by Mitch Manger View Post
I don't know much about particular capacitors, so if you happen to know of one with a 100-200 pF capacitance that you would recommend for making cables for my DPA, that would be wonderful. I still haven't made the cables yet.

Thanks for your post. I think I've seen exactly what you're talking about in an old cable for my B&K preamp and 4003, which I bought second-hand. I'll go check and post later tomorrow.
Try AVX number SA102A101JAR, a 100 pF, 200V COG ceramic cap in a small axial package. You can buy these from Digi-Key -- their stock number is 478-3141-2-ND. For best results, the leads as short as possible, but take care not to melt the part when soldering.

-- David
Old 3 weeks ago
  #15
Lives for gear
If you can pay the piper, the 4003's are the best Omni classical musical mic ever made paired with a Millenia Media 130V preamp. Inky black silence and headroom for days. If you have a great room or hall - this is spectacular. If you have a less than stellar room or need to help out the recording, use ribbons or Schoeps - which will help round out the sound.

I use Canare Quad cable and have no problems with 100 foot cable with the 4003.
Old 3 weeks ago
  #16
Gear Addict
 

Quote:
Originally Posted by piano View Post
If you can pay the piper, the 4003's are the best Omni classical musical mic ever made paired with a Millenia Media 130V preamp. Inky black silence and headroom for days.
Not the kind of thing I'd post normally, but given the speciality of the 130V DPA/B&K mics, allow me:

I have a matched pair of B&K/DPA 4012 cardioids which I purchased from John La Grue of Millennia Media, with documentation and their maintenance history, and, a brand new, never even unboxed Millennia Media preamp, all of which I'm leaning towards selling.

If this speaks to you, let's talk.

Back to your regularly scheduled program.
Old 3 weeks ago
  #17
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tourtelot's Avatar
Quote:
Originally Posted by David Rick View Post
Connect the shell to pin 1 through a small high-frequency capacitor of 100-200 pF.
Great idea. Can I assume that you connect BOTH ends of the cable's XLR shells to Pin 1 through the cap? It would make sense right?

D.
Old 3 weeks ago
  #18
Quote:
Originally Posted by tourtelot View Post
Great idea. Can I assume that you connect BOTH ends of the cable's XLR shells to Pin 1 through the cap? It would make sense right?
Hi Doug. I made this suggestion over a decade ago, and I'd completely forgotten about it. On the internet, no good deed goes unpunished! Hmm, let me think about this...

The RF problem occurs for the middle connector shells when you make a long cable out of two short ones. It's solved if either the male or female shell has a capacitor. At the equipment end, the shell is grounded to the preamp chassis. At the other end, you don't know what the microphone manufacturer did, so if you're only going to add a capacitor at one end, choose the female end.

Nothing says you can't put capacitors in the male shells too, but I think it's twice the work for no clear benefit.

David
Old 3 weeks ago
  #19
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tourtelot's Avatar
Just what I thought, David. Thanks for your thoughts.

D.
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