Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

 #131777  by mgbills
 Tue Aug 27, 2013 9:46 am
What do you think of this??? ... B8788.html

According to the Belden catalog it has 3 shielded strands & 2 non-shielded. I believe the entire outer sleave is shielded as well, like standard Belden.
 #131782  by FretfulDave
 Tue Aug 27, 2013 11:58 am
This is an interesting thread and maybe something on the verge to make the buffer and OBEL wiring systems much better.

I certainly am no expert on the audio side of the equation but I am curious as to how some of the cables pointed out would work and also a word of cautionary note.

A number of cables mentioned are actually computer data cables, cables for RS-232 connectors and what looks to be Category 5 twisted pair computer communication cables.

Cables for RS-232 connections are not going to be very good for this application. They are unshielded and notorious for letting in all sorts of externally generated noise. These are the cables and connectors used to connect from an old style computer to the old CRT terminals and dot matrix type printers of 20 - 30 years ago. These cables could not be used in factory environments due to the extraneous RF and magnetic noise picked up and a different spec, RS-422 was developed to help with that type of purpose. These speicificatons are still used in certain applications but for the most part, they are antiquated in today's world.

The twisted pair cables, i.e. the category 5 type that are shieled, are primarily used for computer to computer communication using the ethernet IEEE 802.3 specification. These cables are specially manufactured and twisted to allow for the best communication of TTL logic circuits, which operate at -5V to +5V and at very high frequency ranges. The twists are put in at very specific points in the cable to minimize cross-talk between pairs. Shielding of the twisted pairs has been added to these cables but it does shorten the effective distance they can carry digital signals but do help considerably in noisy environments.

All that said, it would be interesting to know how something like a Cat 5 shielded or a Cat 6 shielded cable would function in the OBEL setup. I am not sure how well they would work being that they are specifically designed to carry those digital signal levels, which are greater voltages that the guitar pickup put out for sure.

I found this "tidbit" on instrument cables: ... Cables.pdf

though I didn't make it too far through the white paper before my eyes crossed. Very technical reading.

I think the experiments mentioned are an excellent idea and would provide a world of knowledge and perhaps better systems of attaining the OBEL/buffer setups that are so popular on this board.

Best of luck to those who venture into the uncharted waters. It will be of great value to learn the results of such testing.


 #131783  by mgbills
 Tue Aug 27, 2013 1:11 pm
Just so happened that my control electrician dropped by whilst I was wumping my lunch. (Yummy pesto from the garden & wild hazelnuts harvested here in W. Washington.)

Waldo & Dave - Thanks for the redirection. Belden is great for computer/control wire, which lays dormant in line buckets, conduit or wire channel. That Mogami is like SO (service, oil resistant) cord. Like fine rubberized extension cords. I will call up those nice fellows at Redco. I've done some business with them in the past & see what goodies they're hiding.

Thanks for the observations! I was on my way off the cliff.
 #131784  by mgbills
 Tue Aug 27, 2013 1:27 pm
Loved that article Dave.
My employer would not be happy he paid me to read it, but I found it informative.