Recommended cable length for DPA 130v cables

[klaukholm]

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.

[nosebleedaudio]

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.

[klaukholm]

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

[Legacy]

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

[klaukholm]

Thank you for your answer - that helps a lot!

[sonare]

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

[Mitch Manger]

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.

[sonare]

I have never connected the shell and have never had problems with the cables I made for my 4003s.

Rich

[Mitch Manger]

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)

[ghellquist]

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

[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.

[David Rick]

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

[Mitch Manger]

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.

[David Rick]

Originally Posted by Mitch Manger

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