Patchbay failure or patch cables?

bluesfordan

Member
I had something weird happen tonight. I was experimenting with plugins on some recordings of mine. After a while I noticed that my left channel wasn't sounding. There were lights in the meter for the track but no sound through the left headphone. I checked my phones and power amp with another source and they were fine. Back to garage band and still no left. Rebuilt the track and same thing. At one point I put an eq plugin on that track and raised the overall level and the sound came crackling back and worked for a few minutes. About 10 minutes later the sound began to fade and fade and fade until it wasn't working again on the left side.

Finally I checked the patch cables. Pulling the plugs out and putting them back in. A couple of times I was in some halfway position and got sound back on the left side. Finally i pulled the output from gb left cable in and out a bunch of times and the sound worked again.

I rarely touch these cables. They don't get bumped or have things sit on them. Can they get oxidized just sitting inside the PB jacks? Do I have to pull them out and spray DeOxIt or something like that on them every so often? Is this something that can happen when a signal passes through the plug for a considerable amount of time (couple hours?) Maybe this is duh stuff for the studio pros but it is new to me. Thanks in advance for your replies.
 
It could be the connection between the cable and patchbay, but it could also be the normal switching inside the patchbay. It might be a good time to pull it out and spray the switching jacks.
 
Patch cables oxidise more quickly when left plugged in than if they're pulled in and out frequently--the act of plugging serves to "rough up" the cable and the socket on the patch bay.

I'm with boulder...time to get some contact spray cleaner on the sockets and insert/remove the cable a bunch of times.

If it turns out to be something more than oxidation, it could either be the patch bay or the cable--but, in my experience, cables go far more often than any relatively good patch bay.
 
Patch cables oxidise more quickly when left plugged in than if they're pulled in and out frequently--the act of plugging serves to "rough up" the cable and the socket on the patch bay.

I'm with boulder...time to get some contact spray cleaner on the sockets and insert/remove the cable a bunch of times.

If it turns out to be something more than oxidation, it could either be the patch bay or the cable--but, in my experience, cables go far more often than any relatively good patch bay.

I did not know this. Going to pick up some contact spray cleaner. Hmm, our radio shacks have all closed in town. where else can one get some?
 
About the best contact cleaner money can buy......Amazon.com: Hosa D5S-6 CAIG DeoxIT 5% Spray Contact Cleaner, 5 oz.: Musical Instruments

Some of my 1/4" plugs occasionally get intermittent and I just shoot a bit of the DeOxit on a paper towel and wipe down the outside of the plug. I think if you handle the metal jack part of the plugs any amount, the oils and salt (and any other contaminants) from your fingers will eventually lead to poor connections.

Someone on this board had suggested a rifle bore brush for jacks. Don't remember the size/caliber, but something I was going to look into.

6mm might be about right...
Amazon.com : Gunslick Benchrest Rifle Bronze Brush (.243 Caliber/6mm) : Hunting Cleaning And Maintenance Products : Sports & Outdoors
 
pull the whole patch bay out or just spray into the jacks?

I was recently having similar problems with some preamps that happened to be routed through a patch bay. After trying to diagnose the problem as if it were the preamps, I finally got around to troubleshooting the whole signal path. I managed to isolate it to the patchbay, so I pulled it out. I was actually able to leave it connected, just disconnecting one channel at a time and removing that PCB to work on. I sprayed it and inserted/removed a plug several times, as Bobbsy describes. All the weird things going on with the preamps cleared up. Some patchbays don't have separate PCBs for each channel, so you might have to disconnect the whole thing.

My troubleshooting went something like this. I had two channels of preamps, channel 1 giving me trouble and channel 2 working okay. I started by swapping the cables at the preamp end. The problem moved with the cable (problem on preamp 2 connected to patchbay channel 1 and interface channel 1), so the preamp was cleared and the problem was downstream. I then swapped the other end of the cable (at the patchbay, problem on preamp 1/patchbay 1/interface 1 but with a different cable). The cable was cleared, and the problem was further downstream. I then swapped the patchbay-to-interface cables (preamp 1/patchbay 1/interface 2) and the problem moved to interface channel 2 and disappeared on interface channel 1, so those cables were cleared and it was in patchbay channel 1. I double checked by connecting a third interface input to patchbay 1, and the problem moved to that interface input. I then patched the input and output directly with a cable on the front of the patchbay, which cleared the problem up. Everything pointed to the internal switch in the patchbay.

While doing all that I also put my DMM on the connections at various points. Upstream of the patchbay I was measuring no ground connection between the input and output of PB ch. 1. I measured tens of kΩ between hot and cold. Upstream of PB ch. 2 was reading tens of kΩ gnd/hot and gnd/cold. Downstream of the PB was reading 5kΩ gnd/hot and gnd/cold. Channel 2 was somewhat resistive, but at least it had a ground connection. The DMM readings confirmed the patchbay as the source of the trouble and suggested either bad solder joints or crud in the contacts. I didn't bother measuring any other channels. Some of the other preamps were giving me trouble so I just decided to spray the whole thing. After spraying, the resistance on the input side of the patchbay (with the output connected to the interface) indicated that the problem had been solved and I didn't have to worry about solder joints.
 
The other bad thing with leaving cables in the PB for long periods is that the connection springs inside the jacks can get mildly stressed/deformed, and lose their tight spring action...and then you have weak connections....
...and that can not be fixed with sprays.
So exercising the cables and removing them when not in use is the smart thing. I know it's a convenience thing...why disconnect them when I may need them again next week...but it does make a difference, especially with the low-budget bays. Also....many low-budget bays provide jacks on both sides...so even though you are exercising the patch cables on the front...the jacks on the back never get touched.

The heavy duty, pro PBs have much stronger springs, and will last many, many years....and most don't use jacks on the back, rather the wires are soldered or use one of a few specialty connectors that provide near-soldered like connections.
 
The other bad thing with leaving cables in the PB for long periods is that the connection springs inside the jacks can get mildly stressed/deformed, and lose their tight spring action...and then you have weak connections....
...and that can not be fixed with sprays.
So exercising the cables and removing them when not in use is the smart thing. I know it's a convenience thing...why disconnect them when I may need them again next week...but it does make a difference, especially with the low-budget bays. Also....many low-budget bays provide jacks on both sides...so even though you are exercising the patch cables on the front...the jacks on the back never get touched.

The heavy duty, pro PBs have much stronger springs, and will last many, many years....and most don't use jacks on the back, rather the wires are soldered or use one of a few specialty connectors that provide near-soldered like connections.

Is this true also of leaving 1/4 in cables in pedals? what a pain it would be to unplug each one each time.
I have like 8 pedals on a board all connected all the time.
 
Gads this is above my pay grade [and new to me Miroslav :>)
A quick search and right off I run smack into the reverse- and a case for bays 'protecting the gear.

'Patching is not just beneficial to simplicity, it keeps your gear in good nick. Constantly plugging into and out of jack sockets weakens the leaf springs in the socket, and the connection will deteriorate. Leaving something permanently plugged in with a patchbay will improve the life of the jack sockets too.'
I'll just tag along on this one :)
 
I suspect it depends a bit on what type of patch field you use. The ones I'm used to use old fashioned "B-Gauge" sockets and plugs. These are a hold over from the old days of telephone switchboards where patch cables were designed to be in and out of sockets hundreds of times a day. They also have the ability to be "normalised" so semi-permanent connections are made within the patch bay and only need a cable if you want to break the normalisation (in which case plugging in a cable stops the permanent connection).

I might be less confident using cheaper forms of connector but, in 35 odd years in TV, I don't recall leaf springs in the socket ever wearing out--but recall a fair few cases of oxidisation on circuits where, for whatever reason, a cable is left in place long term. However, in this case, a spray of circuit cleaner and a few ins and outs with a cable pretty well always fixed it.
 
Gads this is above my pay grade [and new to me Miroslav :>)
A quick search and right off I run smack into the reverse- and a case for bays 'protecting the gear.

'Patching is not just beneficial to simplicity, it keeps your gear in good nick. Constantly plugging into and out of jack sockets weakens the leaf springs in the socket, and the connection will deteriorate. Leaving something permanently plugged in with a patchbay will improve the life of the jack sockets too.'
I'll just tag along on this one :)

Where did you dig up that nonsense? :D
I mean...if the author of that thinks patchabys are for connecting and then leaving things "permanently plugged in"...WTF would he need a patch bay for?
Just do the hard connections between gear and leave them permanently plugged in...or...normalize the connections on the patch bay.
DUH! ;)

AFA other types of jacks, like on pedals or guitars...yes, all 1/4" jacks work on the principle of leaf springs making or breaking connections from the default, unplugged state. So when plugs are permanently left in for long periods, there is a good possibility that those leaf springs will develop metal fatigue at their bend/spring point...or "memeory"...and when you then remove the plug, the springs don't come back as strong to their default position.

Also...by never removing them, you run the risk of oxidation and dust forming on the contact points...not to mention that some have an additional grounding spring, so that when a plug is removed, the jack will short to ground, mostly to help prevent hum. You can find this on some amp and guitar jacks.
Even your guitar toggle switches operate on the same principal...so when you leave them cocked up/down, they are always applying pressure on the leaf spring.

That said...much of it depends on the quality of the jacks/switches...the better, more expensive ones definitely last longer.

I use the TT/Bantam style of patchbays, and these are ADC or similar quality...very strong, long-wearing jacks. I will leave the patch cables in them during sessions, of course...but I always pull all the cables when I'm done, which lets the springs relax and resturn back to their default position.

AFA pedal boards...I know it might be a bitch pulling plugs, and I wouldn't do it every day after a gig...but it will only make them last longer if you pull the plugs occasionally, clean the contacts, and let them flex back...if it's not problematic. I mean, sometimes you got gear where the backside with the jacks is really hard to get at, so you do the best you can. Every time I have a need to pull my racks out, away from the walls, as much as I hate doing it, I pull and clean all my connections on all the gear...though most of them are XLR, but even they will get oxidation, if no metal fatigue.

It's really about maintenance. It's like changing the oil on your car. You can probably go a long time before it kills the engine...but changing it regularly will prevent the engine dying prematurely. :)
 
I went with a patch bay to be able to do on the fly re-configuring of the ins and outs without the having to pull the components out to see WTF I'm doing back there. If I had thought that patchbays weren't meant to be left plugged in all the time then I probably wouldn't have bothered. Why do studios have them? Because virtually all the connections are on the back sides of everything, where it nearly always black, not always accessible, etc etc. Sometimes I want the computer output (ok, most the time) to go to the power amp, sometimes the CD output, sometimes one of the tape desks (yes, plural). Sometimes I'm dubbing a CD to a tape (why, yes, people still do that, stop staring at me.) Sometimes I'm dubbing a tape to the computer. Granted, mostly I'm using the computer but I don't want to normalize the patchbay so this is my only option.

At this point, after I redid my patchbay in January, everything has been plugged in and left there. Prior to that it probably had been 7 or 8 years untouched. Should I can the dbx and buy a new better PB and maybe once a year have a unpatching de-oxiting and re-plugging party? Or just keep it, and get a rifle brush and deoxit good and then do the yearly party thing?

Man, I can't imagine how bad it must be in a studio where there was smoking allowed. At least my stuff never got exposed to that.
 
There was time when I was young-n-stupid and smoked...cigs and weed, in the studio...and the smoke film that would get on all the gear was nasty. I stopped smoking cigs over 20 years ago...the weed these days is a very rare puff, I just lost interest in it. :D

So AFA the PBs...I'm sure people leave shit plugged in all the time....maybe always?....but there's no need to do that if you just "normal" those connections within the PB, and then use patch cables to "break" those connections when you want to reroute the signals to other gear.

The point was that plugging/unplugging is a natural way to 1. clean the internal contacts and the tips of your patch cables...so you won't get intermittent signal loss or noises, and 2.) if you know you won't use the gear for weeks, months...pulling the patch cables allows those contacts to "relax", and they will last longer and provide a firmer grip on plugs when they are inserted.
These are "best-practices" suggestions...but do what works for you.

Apart from 1. and 2. above...I always like the idea of "zeroing" the patchbay, same way I will zero out my console knobs/faders between sessions.
Re-patching the bays gives me an opportunity to get reacquainted with the signal routing, and also give me an opportunity to consiously consider that's what I want...etc.
Leaving everything always in the same position kind gets boring...and you end up getting lazy and not ever wanting to try something different.
 
As an aside on this, I Googled "patch bay" and at least one of the results was a patch field using RCA/Phono connectors. I wonder if the guy who said plugging was bad for a patch bay was using one of those? :P
 
Corrosion/dirt etc is a real enough prospect and periodically cleaning the jacks and sockets, as described, is a good idea.

I've had the same 1/4" patch bay for about 8 years or more, and it was well used before I got it! Some get regularly switched around, some are permanent.
All need a clean once in a while but none has ever broken.
 
Where did you dig up that nonsense? :D
I mean...if the author of that thinks patchabys are for connecting and then leaving things "permanently plugged in"...WTF would he need a patch bay for?
Just do the hard connections between gear and leave them permanently plugged in...or...normalize the connections on the patch bay.
DUH! :rolleyes:...
What? I think the implication was it was good for the preservation/ware and tear of the dozens of the external unit's jacks. Might patch bay hardware be expected to be more robust and designed for this?
DUH back! [Over/] :rolleyes: :)

Ok, and just to add.. Springs could very well 'weaken.
No patch bay here. But I did have 24 (+/-) TRS's pretty much permanently 'line in on the old Mackie 24-8 for the last 15 - 20 of it's life. They remained nice and snug to the end.
But.. I damned well 'exercised them, pulled and wiped every one of my connections occasionally for maintenance. (Usually 'late, but that's 'cause I'm a lazy no good... :p
 
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This is becoming informative, thank you very much, guys and/or gals. :D

I'm still not sure what is meant by normalizing between connections inside the PB. Always on? Bear with me, here. I've got the output from my computer going to bay 2 left (top) and right (bottom)

my most common connection there would be to the input of the power amp. What would a normalized connection consist of?
 
What? I think the implication was it was good for the preservation/ware and tear of the dozens of the external unit's jacks.

Oh I agree that lots of insertions will add wear to the contact points...but again, be it the wear on them or the springs from permanent contact...it comes down to build quality that you start with.
I just see little point to patching gear "permanently" instead of simply using normalled connections. That way there is very little wear to those points of either type.


I'm still not sure what is meant by normalizing between connections inside the PB. Always on?

Basic concept...a normalled connection is something that you would "normally" want connected most of the time.
It's done a few different ways, either by solder wires internally, or switches, etc...but if you have two pieces of gear, where their I/O's would be connected to each other most of the time...the simple solution is to "normal" their points at the bay...that way you don't need to patch them with a cable. However, you have the option of inserting a patch cable into either set of points, and "breaking" that "normal" connection so you can connect something else instead to that gear.

There are also "half-normalled" connections...which allow you to take a "split" off the points, but still maintain the connection between the "normalled" pieces of gear.

Make sense...?
 
Oh I agree that lots of insertions will add wear to the contact points...but again, be it the wear on them or the springs from permanent contact...it comes down to build quality that you start with.
I just see little point to patching gear "permanently" instead of simply using normalled connections. That way there is very little wear to those points of either type.




Basic concept...a normalled connection is something that you would "normally" want connected most of the time.
It's done a few different ways, either by solder wires internally, or switches, etc...but if you have two pieces of gear, where their I/O's would be connected to each other most of the time...the simple solution is to "normal" their points at the bay...that way you don't need to patch them with a cable. However, you have the option of inserting a patch cable into either set of points, and "breaking" that "normal" connection so you can connect something else instead to that gear.

There are also "half-normalled" connections...which allow you to take a "split" off the points, but still maintain the connection between the "normalled" pieces of gear.

Make sense...?

so a half normaled connection would allow the 'normal' connection say computer to power amp AND if I so desired via patch cable to another piece of outboard equipment for whatever nefarious reason my twisted and warped mind can cook up?
 
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