DB25 alternative cables? (eg. iomega cable ok?)

A place to ask the basic questions, a place for students, newbies, and everyone else.

Moderators: rick, Mark Bassett

DB25 alternative cables? (eg. iomega cable ok?)

Postby EvLoutonian » Mon Nov 10, 2014 6:03 pm

Hi humanoids.

I am hooking up a bunch of gear using D-Sub/DB25 8-way cables for my studio
(via patch bays with D-Sub connectors on the back).

My question is, which kind of D-Sub cables can I use (or what characteristics should they have, etc?) and what types are not appropriate?

For example, I have some commercial style dedicated audio breakout cables (fanning out to TRS or XLR etc), but I also have a few decent quality shorter D-Sub cables that would be great to use if I can get away with it, but I'm not sure how to tell exactly..

For example, I have a couple of short iomega branded cables (that came with ZIP drives).
Can I use them?

I tested the cable pin-to-pin wiring and it's correct. Are there other factors to check (besides just plugging them in and seeing if the audio is clean sounding)?

Do I need to establish what is the overall shielding system, or check twisting of paired conductors or anything like that?

I'm not really sure how I would check.. Hoping someone may have a simplified answer or rule to go by..
- which I suspect may be, "don't be such a friggin tight-arse, young man - go and buy the prescribed pro audio cables at $70+ a piece and be done with it, lad".
Evan Lorden, Well Worn Workshops, Melbourne
EvLoutonian
Registered User
Registered User
 
Posts: 226
Joined: Wed Jun 09, 2010 12:46 pm
Location: Melbourne

Re: DB25 alternative cables? (eg. iomega cable ok?)

Postby gigpiglet » Mon Nov 10, 2014 10:52 pm

i have found DSUB to be a particularly fiddly and difficult system
lots of issues over there years - so now i only use custom built/ best parts/ best labour cables.

having said that, main issue has always been with grounding, and more importantly the physical mounting.
ive found anything with a metal connecter (not plastic) is good and should work well
anything plastic is bad and always seems to have issues (in my experience)

i try and zip tie them in
and not move them too much also.. they seem to wear quickly
Gareth Stuckey
gigpiglet productions:presents:recordings
gigpiglet
Valued Contributor
Valued Contributor
 
Posts: 1120
Joined: Tue Jun 01, 2010 4:10 pm
Location: sydney australia

Re: DB25 alternative cables? (eg. iomega cable ok?)

Postby EvLoutonian » Mon Nov 10, 2014 11:19 pm

Thanks Gareth,

Def appreciate your input from wealth of experience!

Hmm.. yes .. the whole patchbay question has had me going around in various circles for some time now, trying to settle on best layout, best hardware, maximum flexibility etc (etc ETC!)

My initial inclination was to go with the old school military grade B Gauge TELEPHONE style patching bays, with either solder tabs directly on the back or I even started wiring up one bay with huge WINCHESTER connectors on the back (which was standard on some ADC bays)..

But then got to thinking the bantam + DB25 would be more flexible / semi-modular, and potentially more economical in the longer term. But that all depends on reliability, of course.

I do have a few of the larger "B Gauge" style patch bays, but I'm not sure I'd have much luck sourcing enough of those patch cables (or the plugs to make my own) at a rate that I could afford at this stage.

Do you use some multi-pin plugs in your system such as EDAC etc, Gareth?

gigpiglet wrote:i have found DSUB to be a particularly fiddly and difficult system
lots of issues over the years - so now i only use custom built/ best parts/ best labour cables.
Evan Lorden, Well Worn Workshops, Melbourne
EvLoutonian
Registered User
Registered User
 
Posts: 226
Joined: Wed Jun 09, 2010 12:46 pm
Location: Melbourne

Re: DB25 alternative cables? (eg. iomega cable ok?)

Postby Drumstruck » Tue Nov 11, 2014 7:45 am

fwiw I've used cheap parallel cables (i.e. computer to printer DB25 cables) on a PT system and only had issues when the cable length was more than about 1.5m.

With that said, I'd still recommend a better quality cable. I'm currently using HoSa for digital console to outboard (DB25-XLR and DB25-TRS) and they've been very good at lengths of up to 10m - even when using F-F joiners to connect 2 x DB25 cables together. They can get easily dislodged as Gareth implies - I always use the screw-ins on each connector.
Ian Dare
Drumstruck
Valued Contributor
Valued Contributor
 
Posts: 1534
Joined: Fri Sep 17, 2010 12:37 pm
Location: Over the hills and far away

Re: DB25 alternative cables? (eg. iomega cable ok?)

Postby gigpiglet » Tue Nov 11, 2014 9:28 am

evan ive got a full custom built (and mounted into the last bucket of my neve) bantom bay
all solder connections on the rear so we put it all together as we wanted.
i dont think id ever do it again (and the boys how helped would say the same) it was a massive amount of work.
pretty much everything in the studio is EDAC as that is whats on the neve (and was on my old DDA) or solder. but none of that really moves or gets unplugged.
interfaces have DSUB on the back of them, we custom built cables for those (metal shells, canare cable) and other end soldered to either patch or edac inputs to the console.
our live racks are all based on DSUB though, but in a way that the patching is done inside the rack and very rarely changes. eg: DSUB out from 3x midas 8ch pre amps to DSUB in on a joeco. those four bits of gear are in a 4RU case and dont really get changed around - if you want that system you take the whole case with you. again custom made cables to length. metal shells canare or mogami (cause its more flexible) cable. zip tied into place in the racks.

ive never like HOSA dsubs that iam mentions. ive found the plastic shells to fit really loosely, and the screws never to do up just right. but if its sitting in the back of a rack and not being used to much im sure they would be find.

a "trick" ive learnt over the years to save some money/ time but still get a fairly custom result, is to buy whatever cable you want as multi to multi (so in your case DSUB to DSUB) and CUT IT in half. then you can terminate all the ends to the lengths and in the style you want (patchbays, connectors, faned out in the right lengths into a console etc) best of both worlds, for cheaper, and easier on your labour!

db25 has seemed to become the "standard' i would say though (on newer gear - think SSL/ midas/ lynx etc) and when it all works just the way you want its lovely. but you will inevitably have a few loose ends or extra bits and end up wiring up custom panels etc anyway to get the last 2 inputs, or the 1 headphone send, and what have you.
Gareth Stuckey
gigpiglet productions:presents:recordings
gigpiglet
Valued Contributor
Valued Contributor
 
Posts: 1120
Joined: Tue Jun 01, 2010 4:10 pm
Location: sydney australia

Re: DB25 alternative cables? Wiring, etc

Postby EvLoutonian » Tue Nov 11, 2014 10:21 am

Thanks guys. Very much appreciated!

One more question (maybe more particularly for you, Gareth) ..

- With regards to earthing / grounding scheme, do you have an approach where you tie the earth connection to the shell at just one end and not the other? (I think this is a kind of a standard practice of sorts with Male vs Female XLR's, in one direction?) Or do you connect the shield to both of the metal DSub connectors on every cable?

Cheers!
Evan Lorden, Well Worn Workshops, Melbourne
EvLoutonian
Registered User
Registered User
 
Posts: 226
Joined: Wed Jun 09, 2010 12:46 pm
Location: Melbourne

Re: DB25 alternative cables? (eg. iomega cable ok?)

Postby gigpiglet » Tue Nov 11, 2014 9:11 pm

hopefully rob will chime in hear.
but my understanding is the absolute best way is to use entirely balanced connection with both ends of the shield connected to chassis ground.
but thats not always possible, and their are plenty of variables and plenty of bad (or non existent) chasis grounds.
if i "drop the shield" i do it at the "tails" end (ie the multipin/ patchbay/ console which is probably the thing with the trueist chassis ground - keeps it)
does that make sense?
rob? can you explain that better?
Gareth Stuckey
gigpiglet productions:presents:recordings
gigpiglet
Valued Contributor
Valued Contributor
 
Posts: 1120
Joined: Tue Jun 01, 2010 4:10 pm
Location: sydney australia

Re: DB25 alternative cables? (eg. iomega cable ok?)

Postby rob » Thu Nov 13, 2014 10:02 pm

Real world connection between two units fitted with dsub connectors using a dsub to dsub cable will connect the two units common or 0V points together. Strictly following the "rules" this is not the best practice. However unless you handmake your ddsub cable and lift all eight 0V terminations st one plug you have no choice about this.

but never mind because most equipment made these days has pin 1 on xlrs tied to 0V not chassis with chassis isolated from 0V. Purists say this is wrong. In the real world 99% it is fine.

Regarding wiring the shell to 0V is not worth the hassle and has little benefit unless you are in an extreme RF environment.
User avatar
rob
TRM Endorsed
TRM Endorsed
 
Posts: 1002
Joined: Tue May 10, 2005 9:16 pm
Location: Adelaide

Re: DB25 alternative cables? (eg. iomega cable ok?)

Postby EvLoutonian » Thu Nov 13, 2014 10:18 pm

Thanks Rob!
Great to get a simple and straightforward breakdown of those points!
(:
Much appreciated.
Evan Lorden, Well Worn Workshops, Melbourne
EvLoutonian
Registered User
Registered User
 
Posts: 226
Joined: Wed Jun 09, 2010 12:46 pm
Location: Melbourne


Return to You've gotta start somewhere.

Who is online

Users browsing this forum: No registered users and 1 guest