bantam patchbay wiring

seemless001 · Post by **seemless001** » Wed Apr 20, 2005 1:57 am

Hi,
When solder normalling a bantam patchbay with balanced connections, do I need to solder the earth (screen) between connections?
Thanks

Post by **Aaronw** » Wed Apr 20, 2005 2:31 am

You can wire the shield either: (1) Individually; or (2) which is more common, tie all the shields together for one ground.

enthalpystudios · Post by **enthalpystudios** » Sun Jan 15, 2006 5:14 pm

I know that this is an old thread, but, as I'm installing a TT patchbay at the moment, I'm wondering about this.

This is a used patchbay, it came out of an MCI JH416. 6 48point bays. Some half normalled, some full normalled.

It has all the grounds "bussed," and all of it's wiring is still there. Now, all of the wiring coming to the patchbay has it's ground folded back and ignored...... shouldn't these be soldered to the bussed ground on the bay?

Now, for example, I want to have my xlr tie lines come up on the first row, which works out nicely as I'll have 24 xlr tie lines total, and I have a decent amount of outboard pre's (no console), but not 24..... Now what i'm wondering is, if the grounds are bussed, is phantom on 1 channel going to end up in every channel on that bay? And it seems obvious to me that the tie lines and lines to the mic pre inputs need to have their grounds connected to the bay, and it just seems to make sense to me that they should be discrete rather than bussed.

Also, there aren't separate ground lugs for Ground and Ground-Normal.... does that mean that I can't maintain descrete ground path's between mic tie lines and mic pre in's if I normal? I don't need to normal, but I wouldn't mind it.

Anyway, I just figured that there would be 6 lugs on each jack..... but I only have T, R, S, TN, and RN. No Sleeve normal....

Also, on other bay's, where there will be recorder in's and outs and compressor/eq/other outboard ins and outs, I can probably bus all the grounds to a common ground, right? Just run a wire from the bus to a ground bar I assume....

Anyway, sorry for the inundation of questions, and thanks in advance for any answers anyone might have.

Billy

Post by **Aaronw** » Tue Jan 17, 2006 4:31 am

Hello Billy,

Now, for example, I want to have my xlr tie lines come up on the first row, which works out nicely as I'll have 24 xlr tie lines total, and I have a decent amount of outboard pre's (no console), but not 24..... Now what i'm wondering is, if the grounds are bussed, is phantom on 1 channel going to end up in every channel on that bay? And it seems obvious to me that the tie lines and lines to the mic pre inputs need to have their grounds connected to the bay, and it just seems to make sense to me that they should be discrete rather than bussed.

Having all the grounds bussed together is no problem. In fact, it's common. The phantom power actually is on pins 2&3 (24v each). So you shouldn't need to worry about phantom being on the others.

Now, all of the wiring coming to the patchbay has it's ground folded back and ignored...... shouldn't these be soldered to the bussed ground on the bay?

They may have had a ground loop problem w/ the console. Try connecting it, and see if you have the same issue.

Also, there aren't separate ground lugs for Ground and Ground-Normal.... does that mean that I can't maintain descrete ground path's between mic tie lines and mic pre in's if I normal? I don't need to normal, but I wouldn't mind it.

The way I've seen them bussed together, is usually the in's and out's (all the grounds) have been done together.

Make sure your outboard gear patchbay is completely Denormalled, or you'll have it feeding back into itself.

enthalpystudios · Post by **enthalpystudios** » Tue Jan 17, 2006 4:44 am

Ok, so phantom simply uses the ground like a ground, nothing else..... for some reason I thought that would be a problem. That takes most of the sweat off my brow.

Now, if the ground is folded back and not connected to the ground bus, but the other end of the ground is, for example, connected to pin 1 of an xlr, plugged into the input on a piece of outboard gear, and grounded correctly there, but not connected the ground bus at the patchbay, will it ground correctly?

I hear about people disconnecting the ground at one end sometimes, and I wonder why.... should it be connected to earth at both ends?

What are the advantages to connecting at one end versus both?

Thanks so much Aaron,

Billy

Post by **Aaronw** » Tue Jan 17, 2006 6:02 am

Now, if the ground is folded back and not connected to the ground bus, but the other end of the ground is, for example, connected to pin 1 of an xlr, plugged into the input on a piece of outboard gear, and grounded correctly there, but not connected the ground bus at the patchbay, will it ground correctly?

You still want to connect the ground pin of the mic lines to the "ground buss" of the patch bay.

I hear about people disconnecting the ground at one end sometimes, and I wonder why.... should it be connected to earth at both ends?

Sometimes you'll have a piece of gear that is noisy, and will need to disconnect it (especially unbalanced connections), but in general you'll always have the shield connected to the ground bus on the patchbay.

enthalpystudios · Post by **enthalpystudios** » Tue Jan 17, 2006 10:12 am

Cool, thanks aaron.

And just for me to clear things up, by 'shield' you mean the twisted wire that is without insulation in the cable, right? Not the foil that surrounds all 3....

Shame of the matter is that it looks like it's been cut in most places at the bay, so I'll either have to just redo it all, or use some type of 'jumper' to connect them. Either way, it's going to be a big hassle, but thats what it all is in this type of thing.... just got to learn to enjoy it i think ;]

thanks again,

Billy

Post by **Aaronw** » Wed Jan 18, 2006 12:41 am

And just for me to clear things up, by 'shield' you mean the twisted wire that is without insulation in the cable, right? Not the foil that surrounds all 3....

Yeah. Just remove that foil from the wire. They typically call it a "Foil shield w/ drain wire". The uninsulated wire is the shield.

knightfly · Post by **knightfly** » Sun Jan 22, 2006 9:54 am

This just finally "jumped out at me" - "The phantom power actually is on pins 2&3 (24v each)." -

actually, I believe the 48 volt phantom supply is connected to BOTH pins 2 and 3, and center-tapped at the mic with pin 1 being used as ground return; this takes advantage of the balanced line to reduce noise on the phantom supply.

Not that it's a big deal, just so you don't lift the ground and lose phantom to the mic... Steve