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Post by thecolourfulway on Sept 13, 2021 12:19:47 GMT -6
Cue groaning, followed by arguing about having mics come through the patchbay...
I'm installing my first TT patchbay, it has selectable grounding options, which I understand to be - isolated (each jack has its own ground), vertically strapped (the pair has its own ground path), or bussed (shares a common ground path with all jacks on the bussed scheme). After reading some stuff online, I suspect I'll want to use isolated. But, I also found this cryptic note from the manufacturer "This [isolated] setup may present problems for you if you have condenser mics that need phantom power." grr...
I do intend to to have mic lines normaled to preamps on this patchbay. So, what is the deal with iso/bussed ground and sending phantom? I'm kinda looking for a technical explanation here. Thanks!
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Post by Blackdawg on Sept 13, 2021 14:25:47 GMT -6
So for the mic lines you want vertically strapped grounds. This shares the grounds of the top point with the bottom. If you isolated it, you'd break the ground connection to your microphone from the preamp. It'd be like doing a ground lift on a microphone which is bad. So vertically strap the mic patch points and full normal them. And Isolate all the line level stuff to start. You might find some things need different setups but in general this is a good place to start. I like to half normal these. Nice little article from Bittree on this: www.bittree.com/blogs/get-connected/normalling-your-patchbay-part-3-groundingSome of the terms are a little different but pretty much the same. The "looped" section is the same as vertical strapping and refers to the phantom power. |
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Post by Quint on Sept 13, 2021 15:02:46 GMT -6
Cue groaning, followed by arguing about having mics come through the patchbay... I'm installing my first TT patchbay, it has selectable grounding options, which I understand to be - isolated (each jack has its own ground), vertically strapped (the pair has its own ground path), or bussed (shares a common ground path with all jacks on the bussed scheme). After reading some stuff online, I suspect I'll want to use isolated. But, I also found this cryptic note from the manufacturer "This [isolated] setup may present problems for you if you have condenser mics that need phantom power." grr... I do intend to to have mic lines normaled to preamps on this patchbay. So, what is the deal with iso/bussed ground and sending phantom? I'm kinda looking for a technical explanation here. Thanks! What make/model of patchbay are you using? |
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Post by drbill on Sept 13, 2021 17:09:55 GMT -6
You've really got to think through all scenarios. Telescoping in and out has been standard practice in studios since forever, but I eventually ended up bussing all grounds together at the bay itself. Tying down ALL grounds UP AND UNTIL connecting to each piece of gear - where the ground was lifted at the input/output connector. A little unorthodox, but I worked through it with a couple of great electronics / studio install guys, and it's worked out fantastic for me. Easy to change stuff up, and virtually noise free. As a side note, everything is balanced here - bays, wiring, gear, connectors, everything. You've got to work this out in your own studio with your own constraints. You can't blindly "follow the rules" without bending some where bending is needed. Good luck! PS - keep 48v out of the patch bay. Either just commit to not doing it, or do like Quint and put isolated 48v boxes at the base of the mics in the studio. It's cheap, easy, and simple. You save SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO much hassle and complexity, and potential heartache by doing that. |
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Post by thecolourfulway on Sept 13, 2021 18:08:06 GMT -6
What make/model of patchbay are you using? this guy here |
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Post by thecolourfulway on Sept 13, 2021 18:10:23 GMT -6
So for the mic lines you want vertically strapped grounds. This shares the grounds of the top point with the bottom. If you isolated it, you'd break the ground connection to your microphone from the preamp. It'd be like doing a ground lift on a microphone which is bad. So vertically strap the mic patch points and full normal them. And Isolate all the line level stuff to start. You might find some things need different setups but in general this is a good place to start. I like to half normal these. Nice little article from Bittree on this: www.bittree.com/blogs/get-connected/normalling-your-patchbay-part-3-groundingSome of the terms are a little different but pretty much the same. The "looped" section is the same as vertical strapping and refers to the phantom power. Thank you, I suspected as much but couldn't confirm, thanks! |
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Post by Blackdawg on Sept 13, 2021 18:15:48 GMT -6
What make/model of patchbay are you using? this guy hereTHats a great model. Id highly suggest getting the 1U one though not the 1.5U like that one. THe bigger labels are nice but not worth the .5U loss of space. The 1U is solid. |
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Post by thecolourfulway on Sept 13, 2021 19:29:49 GMT -6
THats a great model. Id highly suggest getting the 1U one though not the 1.5U like that one. THe bigger labels are nice but not worth the .5U loss of space. The 1U is solid. That's funny I had a friend say the exact opposite! I already have a 1.5 that I picked up used, but I need a second and I'm torn between the 1 vs the 1.5....ultimately I think I've decided that the best thing for my OCD is to get another 1.5 so my whole rack isn't .5 off  |
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Post by thecolourfulway on Sept 13, 2021 19:31:22 GMT -6
You've really got to think through all scenarios. Telescoping in and out has been standard practice in studios since forever, but I eventually ended up bussing all grounds together at the bay itself. Tying down ALL grounds UP AND UNTIL connecting to each piece of gear - where the ground was lifted at the input/output connector. A little unorthodox, but I worked through it with a couple of great electronics / studio install guys, and it's worked out fantastic for me. Easy to change stuff up, and virtually noise free. As a side note, everything is balanced here - bays, wiring, gear, connectors, everything. You've got to work this out in your own studio with your own constraints. You can't blindly "follow the rules" without bending some where bending is needed. Good luck! PS - keep 48v out of the patch bay. Either just commit to not doing it, or do like Quint and put isolated 48v boxes at the base of the mics in the studio. It's cheap, easy, and simple. You save SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO much hassle and complexity, and potential heartache by doing that. ahh Dr Bill you're a wise man, moreso than me, but I just can't keep phantom out of this bay. I promise if I screw something up I'll let you say, "I told you so!" |
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Post by Blackdawg on Sept 13, 2021 19:37:21 GMT -6
THats a great model. Id highly suggest getting the 1U one though not the 1.5U like that one. THe bigger labels are nice but not worth the .5U loss of space. The 1U is solid. That's funny I had a friend say the exact opposite! I already have a 1.5 that I picked up used, but I need a second and I'm torn between the 1 vs the 1.5....ultimately I think I've decided that the best thing for my OCD is to get another 1.5 so my whole rack isn't .5 off oh ha well in that case go for it! I actually have one if you want one cheap. I think Mine might be a Bittree one..I'll check. But I'd let it go for a steal. I bought it and then realized I didn't like the 1.5 factor. Edit: It is indeed an audio accessories one. Send me a message if you want it! |
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ericn
Temp
Balance Engineer
Posts: 14,919 
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Post by ericn on Sept 14, 2021 17:26:48 GMT -6
You've really got to think through all scenarios. Telescoping in and out has been standard practice in studios since forever, but I eventually ended up bussing all grounds together at the bay itself. Tying down ALL grounds UP AND UNTIL connecting to each piece of gear - where the ground was lifted at the input/output connector. A little unorthodox, but I worked through it with a couple of great electronics / studio install guys, and it's worked out fantastic for me. Easy to change stuff up, and virtually noise free. As a side note, everything is balanced here - bays, wiring, gear, connectors, everything. You've got to work this out in your own studio with your own constraints. You can't blindly "follow the rules" without bending some where bending is needed. Good luck! PS - keep 48v out of the patch bay. Either just commit to not doing it, or do like Quint and put isolated 48v boxes at the base of the mics in the studio. It's cheap, easy, and simple. You save SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO much hassle and complexity, and potential heartache by doing that. Of course a couple of pairs on the bays that function as audio ground lifts is one of those simple audio life rafts worth their weight in gold. |
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Post by svart on Sept 15, 2021 9:03:38 GMT -6
Running a mic input patchbay that used to be normalled to mixer preamps but are now just used to choose external preamps. Never had a problem with phantom through it. I've been fairly careful to turn phantom off before patching stuff, but I've accidentally hot plugged mics and preamps a few dozen times over the years with no failures.
I definitely run each channel ground isolated from the next in the patchbay. I don't see how that can affect phantom.
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Post by Ward on Sept 23, 2021 14:15:24 GMT -6
In my studio, 50' and 100' 54-pair snakes run to the big room and booth and secondary bays. All back to central patch field. At each point, 15' to 25' microphone cables connect to LDCs and SDCs. P48 runs the entire way and nobody ever complains. Granted, everything is discreet wiring and isolated grounding.
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Post by thecolourfulway on Sept 25, 2021 22:04:47 GMT -6
So for the mic lines you want vertically strapped grounds. This shares the grounds of the top point with the bottom. If you isolated it, you'd break the ground connection to your microphone from the preamp. It'd be like doing a ground lift on a microphone which is bad. So vertically strap the mic patch points and full normal them. And Isolate all the line level stuff to start. You might find some things need different setups but in general this is a good place to start. I like to half normal these. Nice little article from Bittree on this: www.bittree.com/blogs/get-connected/normalling-your-patchbay-part-3-groundingSome of the terms are a little different but pretty much the same. The "looped" section is the same as vertical strapping and refers to the phantom power. Ok I've now got a natural extension to this question...what about patching across non-normalled connections in this scenario? So, mic1 is above preamp1, and that makes sense they are grounded together. Now, what if I want to patch mic1 to preamp4, which is grounded together on mic4? And what happens if I send 48v from preamp4, whose ground is tied to mic4...does that ground work correctly with mic1? Does it now create a weird grounding to mic4? Why is this so hard geez! Thanks for any tips y'all, cheers! |
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Deleted
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Post by Deleted on Sept 26, 2021 10:56:09 GMT -6
So for the mic lines you want vertically strapped grounds. This shares the grounds of the top point with the bottom. If you isolated it, you'd break the ground connection to your microphone from the preamp. It'd be like doing a ground lift on a microphone which is bad. So vertically strap the mic patch points and full normal them. And Isolate all the line level stuff to start. You might find some things need different setups but in general this is a good place to start. I like to half normal these. Nice little article from Bittree on this: www.bittree.com/blogs/get-connected/normalling-your-patchbay-part-3-groundingSome of the terms are a little different but pretty much the same. The "looped" section is the same as vertical strapping and refers to the phantom power. Ok I've now got a natural extension to this question...what about patching across non-normalled connections in this scenario? So, mic1 is above preamp1, and that makes sense they are grounded together. Now, what if I want to patch mic1 to preamp4, which is grounded together on mic4? And what happens if I send 48v from preamp4, whose ground is tied to mic4...does that ground work correctly with mic1? Does it now create a weird grounding to mic4? Why is this so hard geez! Thanks for any tips y'all, cheers! Switched ground (vs Looped) would allow cross-patching without the ground connection getting split to two preamp inputs at once. Somebody will fly in to save the day if I'm misinterpreting. From Bittree's FAQ: "So, keeping that in mind for a full normal circuit a buss; looped (vertical strap) or switched ground setting on our patch bays will all pass the ground required. A non-normal circuit at the patch bay does not apply to this concept since inserting a patch cord is required to complete this circuit and ground will then be provided. A half normal circuit is not recommended for phantom power applications.
In summary, again, all Bittree patch bays are capable of passing Phantom Power. Switched ground bays in particular offer the satisfaction of a ground follows patch rule which can be very useful for isolating ground technical issues, notably in systems with many performance, playback rooms or locations." |
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Post by mulmany on Oct 17, 2021 21:29:48 GMT -6
I rebuilt 24ch of my mic/pre amp bay with ground switching TT Jacks. Works great.
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Post by thehightenor on Oct 18, 2021 5:49:30 GMT -6
The cost is crazy with patch bays.
My needs are limited I just wanted all my rack gear on I/O's so I went with a high quality 16 way XLR I/O bay (Like the mastering engineers use)
and custom made Van Damme DB25 to XLR snakes 2x8 .... I was shocked at the total cost of just doing this.
Doing bays properly is very expensive!
I can't imagine the cost of a 96 way TT bay done to a professional standard.
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Post by drbill on Oct 18, 2021 13:01:30 GMT -6
The cost is crazy with patch bays. [snip] Doing bays properly is very expensive! I can't imagine the cost of a 96 way TT bay done to a professional standard. Indeed. I've done it dozens of times in a variety of studios I built. Always expensive. Always worth it long term. This time around my bays are 45 feet from my interfaces. Some of my gear is 60 feet from my bays. (Via soffits, etc.). I did all the wiring myself - so no labor costs, no bay costs (had em already) only cable and connectors (elco's included) - and I'm still $12-15k in..... With bays the materials would be $20k. Then the labor...... :-( |
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Post by johneppstein on Oct 19, 2021 13:26:03 GMT -6
You've really got to think through all scenarios. Telescoping in and out has been standard practice in studios since forever, but I eventually ended up bussing all grounds together at the bay itself. Tying down ALL grounds UP AND UNTIL connecting to each piece of gear - where the ground was lifted at the input/output connector. A little unorthodox, but I worked through it with a couple of great electronics / studio install guys, and it's worked out fantastic for me. Easy to change stuff up, and virtually noise free. As a side note, everything is balanced here - bays, wiring, gear, connectors, everything. You've got to work this out in your own studio with your own constraints. You can't blindly "follow the rules" without bending some where bending is needed. Good luck! PS - keep 48v out of the patch bay. Either just commit to not doing it, or do like Quint and put isolated 48v boxes at the base of the mics in the studio. It's cheap, easy, and simple. You save SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO much hassle and complexity, and potential heartache by doing that. ahh Dr Bill you're a wise man, moreso than me, but I just can't keep phantom out of this bay. I promise if I screw something up I'll let you say, "I told you so!" KEEP PHJANTOM OUT OF YOUR PATCH BAY. DON'T ARGUE ANDF DON'T MAKE EXCUSES. DIt's easy to keep phantom out of your bay. Don't wire it in and DON'T RUN MIC LINES THROUGH STANDARD PATCH BAYS. I use a small extra XLR only bay for mic signals.
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Post by johneppstein on Oct 19, 2021 13:32:27 GMT -6
The cost is crazy with patch bays. My needs are limited I just wanted all my rack gear on I/O's so I went with a high quality 16 way XLR I/O bay (Like the mastering engineers use) and custom made Van Damme DB25 to XLR snakes 2x8 .... I was shocked at the total cost of just doing this. Doing bays properly is very expensive! I can't imagine the cost of a 96 way TT bay done to a professional standard. I use old fashioned Switchcraft bays thay require hand wiring. Jacks come out with two screws. Easy. You DO have to know how to solder, but it you can't solder you have no business in audio.
The old style Switchcrafts are also far more economical than the bays with the fancy hifalutin' prewiring, normalling switches and all that extraneous junk.
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bob
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Post by bob on Dec 1, 2021 9:12:01 GMT -6
would it be a good idea to invest in a phantom blocker for every microphone or bit of kit that could be damaged by phantom power and leave them permanently connected to the kit in question?
Commercial phantom blockers seem to go for about €20-40 a channel. A handful stuck on (at least) my mics for peace of mind when using a tt patchbay would be a super solution if it works.
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Post by soundintheround on Jan 31, 2022 21:30:23 GMT -6
I say ditch phantom power all together....
real men use dynamics, ribbons and tube mics!
But seriously, in my studio I kind of avoid any mics with phantom. I think I only have 1 or 2, and I just use an external floor power supply for them.
Mostly because I use alot of old tube preamps that dont have phantom.
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Post by Ward on Feb 28, 2022 9:59:40 GMT -6
I say ditch phantom power all together.... real men use dynamics, ribbons and tube mics! But seriously, in my studio I kind of avoid any mics with phantom. I think I only have 1 or 2, and I just use an external floor power supply for them. Mostly because I use alot of old tube preamps that dont have phantom. External phantom power supplies are great, but they're still phantom power. The advantage being it just keeps the possibility of phantom power out of patch bays. But it's 'phantom'. So it doesn't interfere with anything not using it, by spec. |
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Post by thecolourfulway on Mar 2, 2022 15:26:39 GMT -6
All good advice, thus far I have not put the mic lines into the patchbay, but it means each mic line is hardwired to a specific preamp so it’s a little weird but it’s working (I never use very many mics). I also only have 1 mic that uses phantom but it’s an essential and I also need to keep the option open for guest mics or new mics. Much to consider…
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Post by Ward on Mar 11, 2022 6:21:44 GMT -6
Back to the broader topic . . . all your electrical lines, from the breakers to outlets, should be run with BX cable, AC-90 12/2 preferably. The shielding goes a long way to keep interference out of every part of your signal chain. If you're in a build, replace ALL the wire. Don't cheap out. As an example: www.homedepot.com/s/bx%2520electrical%2520cable?NCNI-5 |
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