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Routing Microphones through a Patchbay
Old 5th March 2006
  #1
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Kalite Marka's Avatar
 

Routing Microphones through a Patchbay

I know this topic has been discussed on occasions especially here in this link:
https://www.gearslutz.com/board/showthrea...ght=patch+bays
...where couple of the studio owners suggest that it is not a good idea to put mic and mic-pres on a patchbay due to phantom power "screw-ups" that may occur.

Nevertheless it is still not very clear
Is this really an issue for most of you slutz?
Is it OK to put the mics and mic-pres on a balanced TRS patchbay?

Putting the mics and pres on the patchbay is the very reason that I want a patchbay in my system.
Otherwise I can just create a simple mixer-less recording chain integrating my pres, summing and other stuff manually… which I’ve been doing for years and rather not… …especially now I have more outboard gear in my setup.
Old 5th March 2006
  #2
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Rick Sutton's Avatar
 

All the info you need is in that thread, but if you need it summarized here goes:
The issue is with the mic level inputs. The output of the pres is definitely OK on TRS.

But as to mic inputs:

Yes it will work. Some do it. Some don't want to take the risk. Many think that an xlr "bay" is the only way to go . I agree with that. Others still insist that they will remember to turn off phantom every time they patch. Some reply that is dangerous and foolish. Do it at your own risk.

There probably will never be a clear cut, unanimous answer from the GS community on this subject. It comes down to :

1. Spend the money. Do it with XLR's. Never worry about it.
or
2. Save a couple of bucks. Do it with TRS. You might never have a problem.
Old 5th March 2006
  #3
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Quote:
Originally Posted by Rick Sutton
1. Spend the money. Do it with XLR's. Never worry about it.
and it's not even that much money. redco made one for me (8 XLR ins) for a little more than the cost of a new 57.
Old 5th March 2006
  #4
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And avoid "bantam" TRS bays.

Bri
Old 5th March 2006
  #5
My basic understanding is - you are far more likely to get a long term short circuit with a jack / trs / bantam / gpo type connector dangling and making accidental contact with a piece of metal..... Than you are with an enclosed XLR connector.

This type of short can mess up gear like valve mic pre's..

My non tech 2c

And here is Brian, above, warning you away too..
Old 5th March 2006
  #6
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Quote:
Originally Posted by brianroth
And avoid "bantam" TRS bays.
do you mean in general, or for this application?
Old 5th March 2006
  #7
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i got a little xlr patchbay in additional to a few trs ones. now i feel real comfortable bringing some mics to the xlr patch panel. i just keep mixer inputs, outboard, and that sort of thing on the trs bays. i think this is the best of both worlds, i have patch points but i'm sure there won't be any screw ups since the mics are still on xlr.
Old 5th March 2006
  #8
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I have mine Mic box from the studio wired direct to Switchcraft TT 96 Bay (Mogami) and all of the outboard back connectors are on my TT bays too. Never had a problem, BUT YOU MUST be carefull of Phantom power. Since in my studio is 99% of the time used by only me, there is no worries. But If the studio is used by more engineers, It is maybe good Idea to go XLR for the Mic and mic inputs.

Old 5th March 2006
  #9
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Quote:
Originally Posted by rufus13
No one needs that kind of density of jacks in a building-based audio facility. If you are in a mobile truck with major funding, then go for it! The connectors are tiny (fragile), the plugs are expensive or $h1t (sometimes both), installation and modification is a nightmare (and expensive), and what about repair? J
Portland Oregon
Most of us that use TT for our line level patching have large analog consoles that have TT bays built in. Starting with that situation, it makes sense to keep subsequent bays on the same standard. If it has to patch directly to the console TT bay I want the new bay to be TT also. If it is an isolated bay, I usually go 1/4" that I build with new components.
And not to argue the point, as 1/4" bays are certainly fine, but in my thirty five years of patch bay experience (15 on 1/4", 20 on TT) I've found reliability to be good for both. I will give the 1/4" a slight edge in this department if new 1/4" components are used. In used bays I find the TT's to be better, mostly due to the age on pro units available (not the current cheapys in the catalogs, we're talkin' Switchcraft or similar).
Yes, the TT is packed tighter, but with the use of Mogami multi-pair the wiring density doesn't become any worse than a 1/4" bay with something like single jacketed Belden or the like that used to be employed with 1/4" bays that I've used.
As long as they are properly installed with first class components and well maintained both TT and 1/4" are reliable, professional solutions.
As far as price is concerned, there are so many high quality TT bays on Ebay for dirt cheap, that price shouldn't stop you. I've bought, rebuilt and used many pre-owned TT bays with complete success for very limited amounts of cash.

You know, I think we're plowing the same field that we already took care of in the thread referenced in the first post. I guess we must love to talk about this stuff.
Old 6th March 2006
  #10
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Just get used to switching phantom on and off every time you plug or unplug a mic. Every place i've ever seen has a mic panel wired to a patchbay. No pro studios run a mic cable from the mic to the console. Nor does anyone pull the normal cabling out of a pre or compressor that is normalled to the patchbay because they don't want to run through the patchbay. Somewhere along the line, a mic signal is going to go through the patchbay. So just get used to being in control of your phantom power.
Old 6th March 2006
  #11
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i use a Neutrik TRS patchbay going out to a 12 channel snakebox with TRS leads on the fan-out, and XLR on the box..

when i need phantom for condensor mics i use a 3rd party standalone phantom power supply between the mic and the snakebox. For tube condensors, they already came with their own power supply. So i really only have like 6 mics that need phantom, which is exactly how many channels of standalone phantom power i have.

No issues here.
And an advantage of having the mics on the patchbay is i can easily patch anything into a preamp for makeup gain. Its very flexible.
Old 6th March 2006
  #12
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Rick Sutton's Avatar
 

Quote:
Originally Posted by rufus13
why would anyone volunteer thir mic-level signals to go through a PB?
Not me. Seems like asking for trouble. Although I think that some of the posts are confusing patchbays and termination panels. But who really cares. If a fellow wants to run mic level signals through a dangerous and degrading tangle of unneccesary contacts, hey, have fun. I love the smell of burnt resistors in the morning...as long as they're not mine.
Quote:
Originally Posted by rufus13
I understand that this is how many consoles get mic and line-level signals in and out (built-in TT bay), but don't have to like it.
I used to give my old mil spec 1/4" strips to the local thrift store when I pulled them out. Feel kinda bad now knowing they coulda had such a loving home with you. If I find more in the back room maybe I'll send them to 'ya. Maybe we could start some sorta non-profit home for unwanted mil-spec patchbays.
Quote:
Originally Posted by rufus13

I think that the reason for this kind of routing is economics, not that it sounds better than other ways. It's cheaper to run ribbons to edge-connectorized TT bays than allow for a mass-pin connector nearer the channels themselves.
That's probably right on the money. Less real estate means less metal work in the frame also.
Quote:
Originally Posted by rufus13

Gotta drink less coffee on sunday.
Naw, if the coffee is part of the buzz, have another cup. We gotta have something to jaw about. I'll stick with TT's (and new 1/4"s) and you stick with the big boys. It's all good. I guess we do agree that neither of our patch bays is going to see anything less than line level though.
Old 6th March 2006
  #13
500 series nutjob
 
pan60's Avatar
 

even if the mic's are run to a xlr panel would you not still want the phantom power off?
i do understand the issue of shorting when plugging a trs in or out of a patchbay.
so mic's need to come in xlr patch and my choice of pre input also on a xlr and from their trs is fine.
the think this is good from what i have gathered from Rick and a few others.
Old 6th March 2006
  #14
500 series nutjob
 
pan60's Avatar
 

hey the edit function as change, and for the better, cool!
Old 6th March 2006
  #15
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Rick Sutton's Avatar
 

Quote:
Originally Posted by pan60
even if the mic's are run to a xlr panel would you not still want the phantom power off?
Not a bad idea to turn the phantom off, although switching the phantom back on with the mic plugged in is probably not a lot different than plugging the mic into a hot circuit. Some designers, notably Oliver of Tab-Funkenwerk, have a phantom circuit that ramps up...very elegant. With properly wired cables an accidental shot of phantom shouldn't hurt any pro mics, but I feel a lot better plugging in an expensive ribbon or tube mic with the phantom off.
Also, watch phantom around old preamps like original V72's as it can harm the input transformer. Generally, though, it's a pretty safe situation when you stick with balanced cabling and xlr's.

All this talk of phantom brings back some old memories. In the 70's phantom mics were being introduced and the mixers of the day were not equipped with inboard phantom. Another fellow and myself were designing and building external phantom supplies and EV found out about us and took our supplies out on sales trips while they were introducing their first entry into that market (the mic was the CS15). Anyway we got a big thrill (just country boys , 'ya know) when all three tv networks at the time (including NBC which used our supply on the Tonight show with Johnny Carson) started buying them. Years later when I was taking the family to Disneyland I spotted one being used there. We didn't make a lot of money 'cause the things were very labor intensive as we pretty much hand made them in batches of 10 or so, but it was an adventure. Haven't thought about that in years.
Old 6th March 2006
  #16
Gear Maniac
 
Kalite Marka's Avatar
 

What if I want to route my keyboard or a track from my daw through one of my pres?
Go behind the rack?
Old 6th March 2006
  #17
500 series nutjob
 
pan60's Avatar
 

if the pre inputs are on xlr's, your mic's are protected, ( as i understand it and to some degree ) everything else can be on trs after the pre input.
then all you would need would be a few cables that were xlr / trs.
i assume you would still want some normalled mults as well as some inserts at each jucntion?
Old 6th March 2006
  #18
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Quote:
Originally Posted by Rick Sutton
Quote:
Originally Posted by pan60
even if the mic's are run to a xlr panel would you not still want the phantom power off?
Not a bad idea to turn the phantom off
Why would it matter with an XLR patchbay? As long as you don't accidentally hit the chassis with pins 2 & 3, you should be fine, right?

Unlike with a TT / TRS bay where the cable's tip *always* touches the pbay ground channel on the way in / out of the bay (thus potentially causing probs for ribbon mics, not to mention sparks at the patchbay and a temporary short of your phantom power source).

Or am I missing some subtlety to XLR bays?

Also can anyone explain the physics and/or general purpose behind strapping all the grounds in a TT / TRS bay together on a bus? I understand that some people use a ground bus as a way to minimize the problems when patching w/phantom power. But why? What's the concept behind this approach? Surely, when tip/ring touches pbay sleeve, you still have a voltage drop of 24 VDC... Is the voltage drop effectively like parallel speakers, so that each ground channel on the bay sends only a small amount of DC? You would still be shorting your phantom power source, no? And all mics would still get a small temporary current on their ground pins, no?

Thanks!
Old 7th March 2006
  #19
500 series nutjob
 
pan60's Avatar
 

well the only reason i would say to get in habit of shutting off phantom power no matter the batch-bay is i believe it is better if the power ramps up and drains slowly as well. maybe no need it just what i have always felt.
slamming voltage to something just cant be good.
as far as patch bays i was all set to go with some long-frames and have my mic's normaled but now that has changed.
i will now have my mic out's and pre's input's on xlr's.
Old 7th March 2006
  #20
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Rick Sutton's Avatar
 

Quote:
Originally Posted by jtienhaara
Why would it matter with an XLR patchbay?

Or am I missing some subtlety to XLR bays?

Also can anyone explain the physics and/or general purpose behind strapping all the grounds in a TT / TRS bay together on a bus?
I mentioned that it's a good idea to turn phantom off, not because of the xlr "patchbay", but just careful practice when dealing with mics that don't need phantom. So, in general, a good practice to get into. I must admit, though, that in the heat of a session I have accidentally patched about any kind of mic you can think of into a hot input more times than I'd care to count. The mics have survived, but that doesn't make the practice right. If I ever do it with a phantomed input into a ribbon, and heaven forbid, the mic cable has gone bad, there is a possibility of ribbon destruction.

The ground strap thing is something I don't recommend if the patch bay has mic signal on it (hell, I don't recommend mic signal on a patchbay anyway). With line level signals it doesn't seem to be any problem. At least not in my system.
Old 7th March 2006
  #21
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Rick Sutton's Avatar
 

Quote:
Originally Posted by Kalite Marka
What if I want to route my keyboard or a track from my daw through one of my pres?
Go behind the rack?
You can always mult the input of your pre up to your regular patch bay and use it to put your keys or tracks in at that location. Just pull out any mic that might be patched in at the XLR patch point for mics. Of course, turn off phantom power. If you end up with any ground loops due to patchbay ground mults you may have to isolate the pre grounds from the main bay. But I doubt that will come up.
Old 7th March 2006
  #22
w2w
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Can someone clarify something:Are you talking about actual mics being plugged into the bay,as in one end of the mic cable into the mic,the other into a bay,and THEN into a console or pre thru the bay? Im asking because I was going to run my mic pre OUTPUTS into a bay,and then patch those into the recorder inputs(also on a bay).The mic inputs are wired mic-into pre- pre -out into bay...Is this the same thing as stated above?...Thanks.
Old 7th March 2006
  #23
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Quote:
Originally Posted by w2w
Can someone clarify something:Are you talking about actual mics being plugged into the bay,as in one end of the mic cable into the mic,the other into a bay,and THEN into a console or pre thru the bay?
Yes.


Quote:
Originally Posted by w2w
pre -out into bay...Is this the same thing as stated above?...Thanks.
No this is not the same thing. This is generally no problem.

Except...

Well, I have a pre whose output causes sparks at the patchbay, and shorts the phantom power. This seems very odd to me. But the designer of the pre told me to bus all my patchbay grounds together. The designer of the pre is a helluvalot smarter than I am,so I'm trying to figure out why / how the ground bus works, and why it would solve my problem. That's why I'm here in this thread. heh

But otherwise all my other pres are fine -- patch the output all you want, no problem. Ditto for mixing board direct outs, effects, compressors, ... Some homemade DIY gear will short and kill ICs etc, but IME most commercial gear is well protected against temporary shorts.
Old 7th March 2006
  #24
w2w
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THanks for the response.I thought I would be ok but this thread had me second guessing...Thanks!!
Old 7th March 2006
  #25
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yes, once a signal has been brought up to line level ( like the output of a mic pre) the patchbay is the proper place to route it. It's mic level signals that are typically 20 to 60 dB lower than line signals that many feel shouldn't be put into a typical patchbay. Mic signals that also carry phantom power have additional problems in a patchbay environment that line level signals do not.
Old 7th March 2006
  #26
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I once saw a guy fry a ribbon mic in a small, but professional studio using a Soundcraft Ghost and the direct patching method. He simply turned the phantom off on the wrong channel by accident and then plugged it in. Took us about 2 minutes to figure out what had happened. I was sure glad it wasn't my mic.

On the other hand... I have worked in studios (including mine) with VERY complicated TT patching systems (I wired mine myself) and have never had any problems at all. No fried ribbons. No messed up pre's. No problems.

All this to say... there is no tried and true way to avoid phantom power or shorting occurances. If your patchbay is wired correctly it is every bit as safe as a direct connection. It's up to you to not break your equipment.... ya know??
Old 13th March 2006
  #27
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Quote:
Originally Posted by rufus13
http://www.uneeda-audio.com/phantom/

"Phantom Power and TT/TRS Patch Bays
If you're building a studio, this is a bad idea. Avoid it."

Much more and why at the link.

Karl
Well, everyone on here seems to be saying "just don't run mic signals through your bay" and what this guy states quite clearly is "don't hotpatch".

I would never hot pach anyway. Mic gets plugged or unplugged, phantom goes off and then back on.

Does anyone have good reasoning to explain that a mic signal cannot go through a patchbay or that phantom power should not go through a patchbay? Aside from crossing conductors, of course, as this is covered by turning p.p. off...
Old 15th March 2006
  #28
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I'm with Rufus on this. If you have already put together a patchbay then fine, go at it, but if you're still in the design stage, why not do it with XLR's? Fail safe, AND the better contact area (remember, we're talkin' the smallest, most delicate and probably most critical signals in the studio) AND you can keep them seperated from being bundled and possibly common grounded to much hotter signals. What's not to like?
I'm outa here. All the info that you'd need to make a decision is in the two threads. It's your joint so make your choice. No big whoop.
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