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[PookyNMR]

I am in the process of upgrading / expanding my studio.  New cables are needed.  There is a lot of technical BS out there when it comes to cabling and I hoping that someone here can give me the straight goods.

What are some key factors to look for in good cabling?  From the research that I have done the following factors seem to be important:

-Capacitance / Resistance (what measurements should I look for?)
-Composition of conductor (any particular type, OFC, Ag, etc ?)
-Sheilding type
-Insulation type (PVC, non-PVC ?)
-Proper termination

Any specs that are optimal for audio cabling would be appreciated.  Also any hints as to what BS to watch out for would also be appreciated.

Many thanks,

Nathan

[decibel]

I can tell you that once I started using Mogami and Canare quad conductor cable, I noticed a huge difference from off-brand cables(pro co, etc....)  I think it is the Canare that uses a braided shield, and that is a real pain to work with, not impossible, but definitely cumbersome.  

In my opinion they sound really great, but I can't offer any kind of "evidence" for that.

As far as connectors, you can't really go wrong with Neutrik or Switchcraft.  The quarter inch Neutriks are really big and you have to make sure the gear will accomodate the width.

I tend to find what is well made and reliable, and stick with it.  This is the stuff that has worked for me, but I'm sure there are many other experiences and opinions on the subject.

Andy Dodd

[LumenStudio]

I'd like to know as well.  This seems to be the only forum that is really technical about things.  Much more my speed when making decisions that are not influenced by all the noise.

Much appreciated.

Cheers,
Lumen

[PookyNMR]

Andy,  

I'm pretty much sold on the Neutrik connectors.  They seem to have a great reputation among various different groups.  My expereince with them has also been very positive.

You mention the quad conductor cable.  If I'm not mistaken the theory behind that is better noise rejection.  Can you confirm that this is the case?

I've also heard reports that the Canaire cable has better noise rejection than the Mogami cable.  Your experiences?  Any measurements?

Thanks

Nathan

[Rick Sutton]

I bit the bullet and pulled out all the various types of wire my studio had been wired with over the years (from cheap crap to audiophile expensive and everything in between) and completely rewired with Mogami. Really cleaned things up sonically and organized what had been a rat's nest. Highly recommended. Used the standard (non-quad) snake cable and have no issues with cross talk or external noise.

[Brian Roth]

I've had good results with various Gepco cables.  I've also evolved to Neutrik connectors.

Bri

[decibel]

Pooky,

As far as noise rejection....just by looking at the Canare cables, they seem to be built way better than the Mogami.  The braided shield, the fabric strings as filler, ......they just "seem" to be higher quality.  That being said, I have never had noise or reliability problems with either brand.  I don't have any scientific proof, other than  the fact that I have never had to worry about noise problems.  

Canare also has a foil shield version of the quad conductor cable that they reccomend for permanent installations where you won't be bending and moving cables frequently.  That stuff is way easier to work with..


Andy

[fishtank]

In most cases I would avoid the quad conductor cable for studio wiring as it has TWICE(!) the capacitance per foot of the two-conductor version.  While it is true that the quad conductor cable may be a bit more immune to noise pickup, this is usually not a problem in a controlled environment and the potential HF roll off due to cable capacitance is not worth the tradeoff IMHO.

Jensen Transformers has some nice white papers on their website that deal with some of these issues.  Good reading.

[Bob Olhsson]

A lot of us are using digital audio wire because it has to be low capacitance. As far as I'm concerned, silver pinned Switchcraft still rules the XLR world.

[dcollins]

Bob Olhsson wrote on Thu, 09 December 2004 15:20

As far as I'm concerned, silver pinned Switchcraft still rules the XLR world.

Agreed.  With 1800F.

DC

[Rick Sutton]

Speaking of Neutrik and Switchcraft, I was putting together a DB25 to TRS snake for a remote I'm doing tomorrow night. I had some Neutrik TRS connectors that I got with some used Mogami so I used them (normally use Switchcraft). When I checked the new snake with the board I'm going to use I found that the TRS connectors didn't seat snug in the output jacks on the board. Grabbed a Switchcraft and tried it...nice and tight. The Neutriks were loose enough that I couldn't trust them so off they came and on went the Switchcrafts.
Anyone else ever notice this with Neutrik?

[PookyNMR]

Interesting that Bob mentions using digital wire for audio cables.  Is there a suggested capacitance for audio cables (with runs of 50 ft or less)?

Nathan

[fishtank]

Generally, the lower the capacitance the better.  I agree that digital audio cable would be the best choice for low capacitance, but it is about twice as expensive as normal mic cable.  I would personally opt to use the money elsewhere and just stick with good quality *normal* cable while others may feel the extra expense is worth it. With cable lengths of 50 ft or less, I would seriouly doubt that you would notice any difference between the digital cable and good quality single pair mic cable.

Here are some specs from the Markertek Catalog:

Canare DA-206 110 ohm AES/EBU cable  Cap. 14.6pF/FT  Price: .69/FT

Canare L-4E6S Star-Quad Mic cable    Cap. 46pf/FT  Price: $.36/FT

Carare L-2T2S  Single-Pair Mic cable  Cap. 22pf/FT  Price: $.35/FT

[danlavry]

PookyNMR wrote on Fri, 10 December 2004 16:13

Interesting that Bob mentions using digital wire for audio cables.  Is there a suggested capacitance for audio cables (with runs of 50 ft or less)? Nathan

A couple of comments about capacitance:

First, capacitance may be a factor at lower frequency (such as audio). At higher frequencies, unless the cable is reasonably consistent and is terminated in the proper characteristic impedance, one deal with capacitance and inductance issues. For now I will stay with audio signals (low frequencies). Clearly capacitance depends on cable type (including the various dimensions and materials) and on cable length. The key capacitance specification is typically given in pf (pico Farad) per foot.

In order to figure out the impact of capacitance on signal flatness response, one should know the source and load impedances.

Say you are driving a cable (capacitance) C. Your source is 75 Ohm resistive, and the load is high impedance. This is pretty typical to audio. Say you wish to have about 1% loss at 20KHz (less than .1dB). It would take 16200pF of capacitance to do the “specified .1dB damage”. Chances are that your cable capacitance is somewhere between 10 and 100pF per foot. Assuming 30pf/ft, it would take 162 feet for -.1dB at 20KHz.

But say you have a 5KOhm source resistance. You will now lose .1dB at 20KHz with 2.5 feet cable. In fact 54 feet will bring your 20KHz down by 3dB.

There are cases such as a high impedance transducer, a passive attenuator box and more where the cable capacitance matters in terms of amplitude response. But in most cases it is not a flatness response issue. So what is it about?

So far I only touched on the interaction of load and source with the cable capacitance.

The more important factor regarding cable capacitance is the interaction with the analog driver.

Sure it would be great to have zero capacitance, but as always, there are tradeoffs. For example, reducing the inner conductor diameter will decrease capacitance, yet you would not want to overdo it. Thicker insulation of the right material will decrease capacitance, but often as a tradeoff to another important factor.

Cable length is the one factor that is always there. The shorter, the better. In other words, if you need 10 feet, don’t have a 20 feet cable (and don’t role the access into loops, which will act like a pickup antenna).

Are you using balanced or unbalanced mode?

Regards
Dan Lavry

[locosoundman]

Great topic.  I know just enough basic electronics to get myself really confused about this.

Your source impedance is the microphone, right?  So does the impedance of the preamp figure into this at all?  Say I am going from a 150 Ohm mic to a 600 Ohm preamp (I imagine this is pretty common in most live situations with really long snake/cable runs of 100'+).  How does this work with the figures you gave before?

Since capacitances in series actually diminish as they add up, wouldn't the longer runs of cable actually have less overall capacitive reactance in their absolute impedance (total resistance would be going up, capacitance down)?  Wouldn't there also be inductances to consider in a cable of this length?


Best,
Rob