InstaSnake from ETS

[soundtrane]

But Senator, mic signals being analog, what could happen to these? I would think proper shielding may be necessary when CAT5 is going to carry mic level signals...

-vin

[studiomprd]

yes, Vin, and as you know, there is more physics to deal with here.  Mic level signals are in thousandths of a volt, compare to a line level signal which is around a volt.  the same amount of noise gets induced into the wires, but while a very little amount of hum will be noticeable with a tiny mic level signal, it will be insignificant compared to a relatively huge line level signal.  These laws of physics will apply to any wires being used to carry the signals. 

I have used unshielded telephone wiring to caarry audio, and I have used shielded and unshielded 'network' cables as well; the shielded works better!  but to compare shielded network cables to shielded audio cables, the performance in freq response and common mode rejection would probably be very close, but other important factors like flexibility, would be much different...

[soundtrane]

So, you mean to say a well-shielded CATx cable could possibly do the job of carrying mic level signals, right?

[soundtrane]

and about fibre-optics - the lightpipe and all... maybe that will be the way to go soon - for this kind of operation...

[studiomprd]

" you mean to say a well-shielded CATx cable could possibly do the job of carrying mic level signals, right? "

right, and in fact it does carry mic level signals very well, yes I have done it!

the TV trucks are rapidly replacing their "snakes" (aka "audio mult's") with fibre optics...

at one stadium we have installed fibre's between the stadium's TV control room at the north end of the field, and the audio control room at the south, next we'll include the press box(es) high above the midfield!

[Jeff Wexler]

I do have a concern about the transformers saturating at low freqs--that would be harder to test for than freq sweeps....

Philip Perkins

Wolf Seeburg has arranged to have Bill Whitlock (chief engineer at Jensen transformers) run the InstaSnake through complete testing for everything from frquency response, low level and high level distortion, saturation, etc. When we get his report I am very sure it will be the definitive answer to most all of our questions.

-  Jeff Wexler

[wolfvid]

•     The surprising thing is that there are no transformers of any  sort in them [the ETS InstaSnake system]. They are simply wiring adapters that  connect pins 2 and 3 of the XLR connectors to a pair in the CAT-5 cable. All  the XLR pin 1 connections are tied together and to the shield contact of the  CAT-5 connector. So, unless you use shielded CAT-5 cable, there are no shield  connections (which could be a big problem, depending on the grounding status of  equipment at each end of the CAT-5 cable run. Therefore, we ran no curves for  frequency response, distortion, etc. 
  Bill Whitlock, president & chief engineer  Jensen Transformers, Inc.  www.jensen-transformers.com
  

[Jeff Wexler]

I received an email from Steve Lampen with Belden Cable. His comments and reporting of their test results seem to be quite encouraging. I hope to do my own real world tests soon.

"I have been reading a number of posts on ETS's InstaSnake and various

comments about Cat 5/6.  We did tests results about 15 years ago, which I

could easily send you.  The results were, on the worst Cat 5 (now 5e) that

we make (Belden 1752A patch cable) which gave crosstalk on unshielded

pairs (worst case) of -95 dB at 50 kHz, and generally -100 dB on the rest

of the audio band below that.  Then we tried to test Belden 1872A

(MediaTwist) now a Category 6 cable, and the crosstalk between these

unshielded pairs was so low they were below the noise floor of our H-P

(Agilent) 8714ET network analyzer. (Noise floor <110 dB).  One of the

secrets here is bonded-pairs, which give you common-mode rejection far

superior to any other paired cable (audio or otherwise).

If you would like a sample of either one, tell me how much you need and

where to send it.  (You'll have to put on connectors.)  Note that these

are UTP, unshielded twisted pairs.  Unless you need a ground connection

(such as phantom power), I think you would be amazed at how well UTP

handles audio, better than shielded cables.  (Shielding, especially

overall shields, INCREASE capacitance and pair-to-pair crosstalk.) Of

course, the limitations on common-mode rejection in UTP are now the source

and destination boxes and the CMRR on those devices."

[Jan McL]

Thanks, Jeff, Wolf & Belden Cable. I'm in.

Took a Google ride looking for the units you have pictured at the head of this thread, Jeff, and had no luck finding the FXLR side with the pigtail. Any suggestions?

[Jeff Wexler]

The company is ETS and the product line is PA200 Series.

The actual product numbers for the boxes with pigtails is a little bit confusing on the website (and the boxes pictured on the site are not the boxes they are actually making now).

Here is the LINK to the ETS website.

[Jan McL]

Thanks, Jeff, been there, looked around, but I still don't see an FXLR with a 1.5 foot pigtail. Googled and found other sites that offer the MXLR with pigtail (notably Markertek with a great price), but they don't offer the FXLR option. Guess I could change the connectors, but...why?

Guess I'll give ETS a call on Tuesday.

Jan

[soundtrane]

from their faq:

What about return channels?

PA202F has 4 Female XLRs (the send unit) and PA202M has 4 Male XLRs (the receive unit). On the PA203 set we have one channel reversed for a return signal. **We offer XLR gender changers so the user can customize a number of InstaSnakes to match his or her exact needs.**

[Jan McL]

Looked at the fact sheet (http://www.etslan.com/pdfdocs/Audio/PA200_Series_InstaSnake.pdf) and the model numbers are:

PA202P = (4) MXLR 1.50’ pigtail to RJ45 jack, all pins; and

PA202FP = (4) FXLR 1.50’ pigtail to RJ45 jack, all pins

Can't order the PA202FP by clicking on an "add to cart" link.

Will order via email Sales@etslan.com

You really gotta work for it.

This solution actually kinda makes me look forward to the next car rig day.

Jan

[Jeff Wexler]

Hey, Jan, in one of my posts I did mention that the part numbers and ordering were a little odd, confusing, and when I first ordered mine I actually ordered 2 boxes with Males on each end (thinking I was going to change out some or all of the connectors myself). I got a call from Tony (main guy at ETS) telling me that I had made an improper order, that I needed both a "send" unit and a "receive" unit. So, he adjusted the order and I got the right stuff. I also ordered some cables made up, shielded CAT-5e with Neutricon connectors, which was quite reasonable considering the Neutricon connectors are $19.00/each.

If you are going to order you could probably call and speak with Tony. He has been following all of this and would be happy to make sure you got the right stuff. Telephone: 510-656-2012.

A word of caution: I have not yet determined the susceptibility to induced noise, a real issue when doing insert car work with the crazy cable runs, so if you want to wait to be safe that might be a good idea. If not, go ahead and get a set and see how it works.

-  Jeff Wexler

[Jan McL]

A quick update. Spoke with Michele of ETS and not only did she get the units in the mail the same day, but gave me a steep ($206 for both units) discount. Don't say I sent ya

She says putting the PA202FP on the website is "on the list" of stuff to do.

[Jeff Wexler]

I was able to do a little testing today on the set of a TV pilot that Shawn Holden, Don Coufal and Robert Maxfield are on. We hooked up the InstaSnake and I wrapped the boxes, the microphone and the cable all in a ball and laid it down on top of a 12K HMI feeder cable. There was definite BUZZ on the line. I then separated this tangled mess, moved the boxes and mic away from the HMI cable and then just wrapped the coiled CAT-5e cable so it would be touching the HMI cable --- NO BUZZ in this situation. This is not to say that there will never be an induced noise problem with the CAT-5e cable but I am convinced that induced noise will be no greater problem with CAT-5e than it is with standard multi-pair mic cable.

We'll see what happens the first time I use it on an Insert Car/process trailer.

-  Jeff Wexler

[soundtrane]

Jeff, is this the CAT5 unshielded cable?

[Jeff Wexler]

Jeff, is this the CAT5 unshielded cable?

The CAT-5 cable has to be shielded variety otherwise it does not pass phantom power to the microphone. You must confirm that it is really shielded cable --- I thought the designation "CAT-5e" meant that it is shielded but that may not always be the case. The cable that I tried on set today, Shawn's regular CAT-5 cable that she uses for video assist, had "CAT-5e" printed on the cable but it did not pass phantom power. The cable may have been mis-printed or something.

- Jeff Wexler

[studiomprd]

Cat 5e is not necessarily shielded, as you have found.  the "e" is for extended, as the spec's were improved to allow longer lines.  shielding is a completely separate designation.

[soundtrane]

reading up on Category 5 cable. the 'e' stands for extended which is up to 350 Mhz...

from wiki:

Shielded twisted pair (STP or STP-A)

STP cabling includes metal shielding over each individual pair of copper wires. This type of shielding protects cable from external EMI (electromagnetic interferences). e.g. the 150 ohm shielded twisted pair cables defined by the IBM Cabling System specifications and used with token ring networks.

Screened unshielded twisted pair (S/UTP)

Also known as Fully shielded[citation needed] (or Foiled) Twisted Pair (FTP), is a screened UTP cable (ScTP).

Screened shielded twisted pair (S/STP or S/FTP)

S/STP cabling, also known as Screened Fully shielded Twisted Pair (S/FTP), [2] is both individually shielded (like STP cabling) and also has an outer metal shielding covering the entire group of shielded copper pairs (like S/UTP). This type of cabling offers the best protection from interference from external sources, and also eliminates alien crosstalk.

Note that different vendors and authors use different terminology (i.e. STP has been used to denote both STP-A, S/STP, and S/UTP).

-vin

[soundtrane]

I have a good feeling about STP - maybe that's what we need out here...

-vin

[studiomprd]

telephone service has traveled for many years as an analog signal on unshielded twisted pairs!

[Jeff Wexler]

Cat 5e is not necessarily shielded, as you have found.  the "e" is for extended, as the spec's were improved to allow longer lines.  shielding is a completely separate designation.

I realize that now, and thanks to Vin I have an even broader knowledge of all the varieties of CAT network cable. The cable that Shawn had said CAT-5e and also had UTP (which I know stands for UN-shelieded twisted pair) and this will not pass phantom power. As for the ongoing discussion of vulnerability to induced noise on the cable, I have had a lot of good input from the rep at Belden Cable and I think with the proper choice of CAT-5e shielded cable we will be good to go.

The reference to unshielded twisted pair cable for analog telephone transmission really has little relevance to the issue of our use --- most all telephone installations are fixed installations with proper consideration for the path that the cable will take; in our situation we have to always be negotiating with electric dept. "you're not really going to put that ballast on top of my cable are you?"

[studiomprd]

sorry you didn't care for my reference to telephone lines, but telephone lines go everywhere, and make long runs, go through many junctions, and endure a lot of potential for interference. true, telephone signals are a lot more robust (in level) than microphone signals, but I think the long standing, widespread common use of twisted pairs (including network cables) speaks well of the physics of twisted pairs.

and after all, the improvement of "star quad" type cables (usually  also shielded!) comes from the same physics.

anticipated performance is great, but the physical construction may not lend itself to long field service; most UTP, and telephone wiring is solid copper, and with less additional construction features for strength and flexibility, amongst other things.

[soundtrane]

Jeff, I guess Senator was trying to bring in a relevance to our overall knowledge of this system, not really as 'applicable' to OUR specific usage of the system.

I knew there was something called STP for many years now, but until now it was irrelevant to me - until these new ways of sending and receiving audio have come up.

I am sure STP cable (the best there is available) will still be cheaper than starquad mic cable. and more robust in many ways...

-vin