cable lenght (fiberoptics) adat to adat bridge

[olek]

Hi,
im usin' the following setup:

-Pro Tools 4.3.2
-MTP AV as Masterclock
-Adat slaved via MMC from MTP AV (9 Pin D-Sub)
-Adat Brige slave via Digi Superclock from MTP AV

the cable length from adat to bridge is 10m optical cable (plastic).

When playing adat files via light pipe to bridge into Pro Tools i sometimes do get drop outs on all channels simultaniously. Not so on the channels converted by the 882i/O.

Does anyone have problems like this and how can i solve them?
Someone told me the the quality of plasticfiber might be to bad and usin' real glass cables might solve the problem.

Any sugesstion?

Thanks Georg

[georgia]

on single mode fiber cables, even the slightest kink will degrade the light path and cause excessive problms. Check you cable for any kinks or tight bends. High quality fiber cable will help.

[This message has been edited by georgia (edited February 16, 2000).]

[Lee Blaske]

I'm getting ready to hook up an Emu E4XT Ultra via light pipe to an ADAT Bridge in the machine room using 10 Meter cables made by Sonorus. Is this the brand you're using?

Regarding higher quality cables (glass vs. plastic), does anyone know where to get them? On the daw-mac mail list, someone suggested Spectran. I emailed them with no response. I called them and got put through to one of their engineers and left voice mail for awhile. Finally I got through to Jim Miller, and he told me that it was possible, and that they would be faxing me a quote. I waited and waited. I then called and left about six messages on his voiemail with no response. I guess I just have to assume that they're not interested in doing business.

Does anyone know of a source for custom length, high quality glass cables? Is it possible to buy a spool of stock and splice on the ends yourself?

Also, I heard that the glass cables are much thinner and more fragile than the plastic cables. Has anyone else found this to be true?

Lee Blaske

[DigiTechSupt]

Olek,

We support Optical cable lenghts of up to 30 feet. As others have pointed out, higher quality cables are necessary for longer cable lenghts. Do you get the same result with shorter cables? If so,the drop outs you are experiencing could be a result of bad clock. Be sure your clock routing and settings are correct.

Jake Schaefer

[olek]

<BLOCKQUOTE><font size="1" face="Arial,Helvetica,sans-serif">quote:<HR>Originally posted by DigiTechSupt:
Olek,

We support Optical cable lenghts of up to 30 feet. As others have pointed out, higher quality cables are necessary for longer cable lenghts. Do you get the same result with shorter cables? If so,the drop outs you are experiencing could be a result of bad clock. Be sure your clock routing and settings are correct.

Jake Schaefer
<HR></BLOCKQUOTE>

Thanks,
you are right, there are npo problems with shorter cables. But where can I buy good, long cables? My main partner is Thomann in Treppendorf/ Germany. Any names of companies that produce good qualitiy cables?

Olek

[Fokke van Saane]

Food for thought.
Would it be possible to convert the ADAT pipe to coaxial (using the boxes originally made for sp/dif), run the lenght by coaxial and then convert back to lightpipe? I Believe the bandwidth of coaxial is bigger.
Fokke van Saane
The Netherlands

[Gary Stadler]

Fokke, it would probably be possible, but if Digi and Adat people did their engineering properly, the bandwidth of optical is WAY greater than almost any piece of wire. The problem with optical cables is simply that the LED (or laser) on one end is only so bright, and the optical signal gets dimmer as the cable gets longer because of optical losses. Glass fibers are much better than plastic fibers with regards to light loss, because of different methods availiable to the glass guys to keep the light from being attenuated in a long cable...Plastic cables are going to be much less expensive however, because a plastic cable will usually have one large diameter fiber in it where a glass cable will have a bundle of many small fibers inside.
Bottom line: It's not a bandwidth problem.

Here's a URL from the only company I could find regarding glass fibers for adat: http://www.merging.com/products/onouris.htm

In the fine print at the bottom they mention that they can supply glass fiber cables...

[Lee Blaske]

Gary,

Thanks for posting this. I've been looking for something like that for a long time.

If find it interesting that glass cables can't simply be plugged into ADAT Bridge inputs/outputs. I wonder if the Onuris device adds any delay.

Lee Blaske

[Lee Blaske]

Olek,

If light (signal) attenuation is the problem, your system must just be on the edge of functioning. In addition to straightening out any kinks in your fiber optic cable, I wonder if blowing out the plug/jack with compressed air might help. I would imaginge a small amount of dust could have a negative impact on things.

Lee Blaske

[Lee Blaske]

Thought I'd post this...

I installed my second ADAT Bridge today, and hooked it up to an Emu E4XT Ultra via light pipe cables 10 meters long (coming and going) and everything is working just fine.

The 10 Meter cables were from Sonorus.

Lee Blaske