Patch bay wiring and grounding.

I'm just about to wire up a 48 point patch bay, and i wonder if I should bus the grounds together or not?

That all depends......
seriously, there are so many possible variables
is it going into an existing patchbay system?
Will it tie into any other patching systems?
Is it all line level?
If it is the only patchbay on a system, it is best to treat it like it was an internal patchbay: buss the ground to all the patchbay jacks, run a nice heavy single ground wire from the buss to the console (or system) ground= star center
tie all shields at patchbay
lift all shields at equipment.
Of course the wrinkle is mic lines, tie the shield at the mic input panel connectors.
it can be best to treat the mic lines and preamps in a seperate bay or section, and do not buss ground there, jumper the top jack ground to the bottom jack ground, and tie the shield to pin 1 of the preamp input. Treat the preamp output to the bussed area

yeah see, this topic is so incredibly confusing.

It's going to be the lone patchbay, with all the ins and outs of everything. Mic pres, compressors, computer i/o, console i/o, and the mic lines from the live room.

think star ground...

one point of ground reference for the entire studio

In an ideal world you should have you patchbay setup with ground busses on all line level signal.

Mic inputs from the studio should be vertically linked to their respective preamp inputs, or not linked at all, just a straight threw patch point to mic lines.

Your console should be grounded on both ends of interconnect cable, bonding the console ground to the patchbay ground. Making the console your "ground source" for the patchbay and the studio (one point of reference)

All outboard gear (line level, not mic inputs) should be lifted at input and output connections, isolating the individual ground references of each piece of outboard gear from the main ground of the patchbay.  Making the patchbay/console ground your only point of reference.

NOW... this is how I've hooked up studios that I've wired from the ground up with great success. Occasionally I'll have to tinker with some finiky gear that needs to be grounded, but from personal experience this method of making the patchbay a ground block and the only point of reference is very reliable.

With that said, I've been in dozens of studios that have been hacked into for years and years and the original ground scheme of the room (if there was one) has long since been demolished and gear is randomly grounded and lifted and patchbays are bussed and not bussed so on and so forth... yet the room was perfectly functional and dead quite as far as interconnects were concerned with the patchbay.

Then there's the consideration of power ground with the studio. This method of patchbay grounding I described is meant to help avoid ground issues caused by multiple power grounds in the system.

I'm not stating this as the one and only way to wire a patchbay... just a suggestion. 

Many people lift all output ground and leave all input grounded... this works too. It's all about individual studio situations and personal preference. If it works it works!

good luck!

Thanks for the info guys, I'll do a little more pondering and then just give er.

At work, we run ours earth-free, just with twisted pairs in an overall grounded shield.

maybe one bay or device at a time and listen as you go
would hate to do all the work only to find out you need to
do more . try writing it out block diagram on paper and see
if you notice anything

the only problem i ever had with the unbal out on my g.r. mp2 was
a studio that did not ground the patch bay

Sarcastic Sound said:

think star ground...

one point of ground reference for the entire studio

In an ideal world you should have you patchbay setup with ground busses on all line level signal.

Mic inputs from the studio should be vertically linked to their respective preamp inputs, or not linked at all, just a straight threw patch point to mic lines.

Your console should be grounded on both ends of interconnect cable, bonding the console ground to the patchbay ground. Making the console your "ground source" for the patchbay and the studio (one point of reference)

All outboard gear (line level, not mic inputs) should be lifted at input and output connections, isolating the individual ground references of each piece of outboard gear from the main ground of the patchbay.  Making the patchbay/console ground your only point of reference.

NOW... this is how I've hooked up studios that I've wired from the ground up with great success. Occasionally I'll have to tinker with some finiky gear that needs to be grounded, but from personal experience this method of making the patchbay a ground block and the only point of reference is very reliable.

With that said, I've been in dozens of studios that have been hacked into for years and years and the original ground scheme of the room (if there was one) has long since been demolished and gear is randomly grounded and lifted and patchbays are bussed and not bussed so on and so forth... yet the room was perfectly functional and dead quite as far as interconnects were concerned with the patchbay.

Then there's the consideration of power ground with the studio. This method of patchbay grounding I described is meant to help avoid ground issues caused by multiple power grounds in the system.

I'm not stating this as the one and only way to wire a patchbay... just a suggestion. 

Many people lift all output ground and leave all input grounded... this works too. It's all about individual studio situations and personal preference. If it works it works!

good luck!

Click to expand...

I'm upgrading the stock patchbay in a Sound Workshop Series 40 console which was designed to use bussed grounds. Some connections coming from the console have the shield connected to the patchbay, others have the shield clipped/lift and receive ground from the patchbay bussed ground.

As such, I decided star chassis grounding was probably the best implimentation for my studio.

The question becomes, what do I do with the shield for all the other outboard gear, tape machines, etc? This post seems to imply (and it makes sense to me) that I shouldn't connect any other shields to the patchbay coming to/from any line level sources. I would only connect the pos/neg leads for all line level i/o and ground for everything would come from the bus, which would connect to the ground plate.

" All outboard gear (line level, not mic inputs) should be lifted at input and output connections, isolating the individual ground references of each piece of outboard gear from the main ground of the patchbay.  Making the patchbay/console ground your only point of reference."

This makes the most sense to me because there would only be one path to ground as long as all the gear is also chassis grounded to the ground plate.

Other folks seem to imply that you shouldn't lift ALL shields, but ONLY input shields or ONLY output shields, and that you need to stay consistent.....although my console has a mix of some ins and some outs with shields lifted (not sure why this is).

I'm no expert in grounding or electronics in general, but this doesn't make sense to me. If you connect the shield, say only at the input, then you would seem to have two paths to ground, one through the shield on the input connection, and one through the AC ground/chassis (unless you completely lift the third prong, which isn't a good idea for obvious reasons).

Is my thinking wrong on this? Is there anything wrong with lifting/cutting the shield on ALL line level inputs AND outputs in a star chassis bussed ground configuration?

Thanks fellas!