Venue Snake

[dstagl]

Do we have to use Belden cable for the snake or would equivalent cable from another manufacturer work?

Dave

[Sheldon Radford]

Hi Dave,

We're working on qulifying other cable types from other manufacturers (VDC, Canare) but for the time being the Belden cables spec'ed are the only officially supported cables.

Sheldon

[dstagl]

So no Gepco, yet?

So what is most likely to happen if a cable that hasn't approved were used, and didn't work?

Dave

[Sheldon Radford]

Hi Dave,

The failure modes can vary from random CRC (data) errors to a complete loss of communication between stage and FOH. The D-Show software will report these errors - but by then it's too late! An inferior cable may also interfere with auto-switching to a redundant backup cable. The digital snake uses a high bandwidth signal that has fairly tight tolerances compared to video signals which use the same type of cable, so it's the one piece of the system you definitely don't want to compromise on.

Sheldon

[dstagl]

Gotcha. Figured I'd check.

Thanks,
Dave

[eytan]

The cables mentioned in the VENUE spec sheet are Belden 1855A and 1694A. These are both single coax cables. The cable that is supplied with the VENUE is a pair of coax cables in one jacket (I received the console in Europe, maybe it's different in the US).

Is that a special cable made for this console or is it a standard Belden cable? What is it's model number?

[Sheldon Radford]

Hi,

The digital snake sold by Digidesign is a special assembly that bundles two lengths of 1855A in a single jacket. Belden offers bundled versions of the same cable in various multi-conductor combinations (but not a two conductor version, hence our "custom" cable). The three conductor version is particularly useful because it provides a spare conductor in the event one of the leads is somehow damaged.

Belden part numbers for snakes 250' or less:
1855A - single conductor
7787A - three conductor
7788A - four conductor

Belden part numbers for snakes 500' or less:
1694A - single conductor
7710A - three conductor
7711A - four conductor

[dstagl]

Belden part numbers for snakes 250' or less:
1855A - single conductor
7787A - three conductor
7788A - four conductor

Belden part numbers for snakes 500' or less:
1694A - single conductor
7710A - three conductor
7711A - four conductor



So, Sheldon, help me with this if you can. We're installing 2 stage racks. If we have a 500' run, and I'm going to buy bulk Belden cable, what's the best way to do this. Should I get 4000' of 1694A and make 8 500' cables or is there a better way to do it with the three or four conductor? Can I get 2 500' cables of 7711A instead?

Thanks,
Dave

[Sheldon Radford]

Hi Dave,

I'd recommend using one of the bundled versions, because it's fewer cable pulls and the jacket offers some additional protection. Whether you choose the three or four conductor version depends on a few things, such as cost, the location of the stage racks relative to each other, and the desire to have spare conductors available for emergencies (which may prove to be useful in a fixed installation where you don't have immediate access to the snake run).

A total of 8 conductors are required for a truly redundant, dual stage rack system. This could be handled by four runs of 7710A, which would give a spare conductor for each connection, or you could scale back to three runs (9 conductors total) and have a single spare conductor to use as needed.

If the stage racks are located near each other you could also use two runs of 7711A (4-conductor). Be sure to split the connections between the cables as shown below. (I.e., don't run the primary and backup for a single stage rack down a single cable). This scheme allows for one cable to be completely severed and still switch to the backup cables carrying all stage channels. This does not, however, give you any spare conductors. One or two single runs of 1694A might suffice for spares, if desired.

Using two Belden 7711A (4-conductor) cables

Cable 1
Conductor 1 connects Stage 1 Snake 1 Out to FOH Snake Card 1 Snake 1 In
Conductor 2 connects Stage 1 Snake 1 In to FOH Snake Card 1 Snake 1 Out
Conductor 3 connects Stage 2 Snake 1 Out to FOH Snake Card 2 Snake 1 In
Conductor 4 connects Stage 2 Snake 1 In to FOH Snake Card 2 Snake 1 Out

Cable 2
Conductor 1 connects Stage 1 Snake 2 Out to FOH Snake Card 1 Snake 2 In
Conductor 2 connects Stage 1 Snake 2 In to FOH Snake Card 1 Snake 2 Out
Conductor 3 connects Stage 2 Snake 2 Out to FOH Snake Card 2 Snake 2 In
Conductor 4 connects Stage 2 Snake 2 In to FOH Snake Card 2 Snake 2 Out

[dstagl]

I would love to use Digi's snake cables, however do you have any idea how expensive they are compared to me just purchasing bulk cable? I received a quote for four 250' snakes that came to 3X the price of 4000' of 1694A. I can't justify spending that much more on cables that give me the benefit of color coding. The added labor of pulling more cables and having one of my guys terminate them is still a rather large savings on our end. If you can get our vendor to sell me four 500' snakes for the cost of 4000' of 1694A, I'll do it.

Dave

[eytan]

Hi Sheldon,

I checked the Belden catalog. The 3 and 4 conductor cables have solid conductors. I will be using the Venue mostly for touring. Are these cables flexible enough for this application?

Regarding connectors, which BNC connectors would you recommend for these cables?

[Sheldon Radford]

Hi,

All of the Belden cables listed are solid core, including the ones used in our Digidesign snake. These cables have proven to be flexible enough for all applications and have held up well to daily wear and tear on the road. The 1694A cable and its bundled variations are slightly less flexible given the larger conductor size, but are still considered quite manageable.

We recommend Neutrik rear-twist connectors, part numbers as follows:

cable type: 1855A connector: NBNC75BDD6
cable type: 1694A connector: NBNC75BTU11

Sheldon

[FOHMIXER22]

Sheldon,

I'm using the 1694A cable with the Neutric connectors and I'm getting an CRC error. It appears to be a random event. Any thoughts? I'm fixing to take it out on tour for 2 1/2 weeks.


Thanks,

Kyle

[Sheldon Radford]

Hi Kyle,

A few questions:

What length of 1694A is being used between Stage and FOH?

Are all snake cable runs between Stage and FOH the same length, or is there a mix of short and long cable runs? All snake cables should be matched to within 10' of each other.

Sheldon

[dstagl]

We were originally getting CRC errors as well, but it turned out a couple of the cables hadn't quite been terminated properly. Since they were re-terminated, we haven't had any problems.

Dave

[FOHMIXER22]

Sheldon,

The cables are 300ft long and within an inch of each other in length. I only saw the messages in rehearsals, luckly not on the road. I powered everything down and re-seated all of the connections. i haven't seen it since. It just makes me nervous.

I have this desk out on tour with Olivia Newton John. It sounds amazing!!!! Do you have any recommendations for hard drives to record with for Pro Tools? Thanks for the quick response!

Kyle

[Sheldon Radford]

Hi Kyle,

Sounds like you're well within spec. A CRC error indicates the receiving end of the snake didn't receive the data it expected from the transmitting end, which is typically caused by cabling-related issues. Check that the cables are terminated correctly, as Dave suggests.

Keep an eye on the situation, and if you begin experiencing more consistent CRC errors don't hesitate to contact our Customer Service folks so they can help get to the bottom of it.

The Glyph GT103 (http://www.glyphtech.com/site/products_gt103.html) FireWire chassis w/ removable drives comes highly recommended from those who've used it. It's a single rack space unit that supports up to 3 drives simultaneously.

Glad to hear you're enjoying the console!

Sheldon

[eytan]

We recommend Neutrik rear-twist connectors, part numbers as follows:

cable type: 1855A connector: NBNC75BDD6
cable type: 1694A connector: NBNC75BTU11

Sheldon



Hi,

I got the Belden cable and I ordered the BNC connectors. I have very little experience with BNC crimping. Do I have to get the (very expensine) Neutrik crimp tool and dies or can I get something less expensive? I have a crimp tool that has a 4 mm hex crimp, will that do the job (Neutrik recommends 4.53 mm)?

Thanks,

Eytan

[Sheldon Radford]

Hi Eytan,

If the BNC ends aren't crimped properly they can compromise the signal, or be prone to falling off altogether. I can't make a recommendation other than the Neutrik crimp tool, so I sugest asking the cable vendor for recommendations to see if there's a less expensive tool that will still give the proper crimp.

Sheldon

[grindx]

If you want Belden quality at a reasonable price, go with Clark Wire.(See www.clarkwire.com (http://www.clarkwire.com)). They have 1694A and 1855A equivalents(RG6SD and DSM respectively). I have used their stuff for years and it is of excellent quality. However, they do not have a 1694A snake, but they do have an RG59 size digital cable snake with better attenuation specs than the 1855A. It's called CV7559. It should allow for a longer run than the 250' for the 1855A, but not as long as the 500' for the 1694A.

All of these coax cables are solid copper center conductor cables with gas-injected dielectrics. they have to be constructed this way to be considered digital cables. They do have a shorter bend life than a stranded center conductor cable. Treat them well and store them on cable reels with as large a drum radius as possible.

Oh, and if you need true 75 Ohn BNC connectors, and when I say true I mean plus or minus 2 or 3 Ohms, use ADC BNC's. Other brands are off by as much as 10 or 15 Ohms. Most won't even show you their Smith charts. While I like the ease of use that the Neutrik rear twist BNC offer, they do not pass a signal as cleanly as the ADC BNC.