[kgveteran]

So, I've hooked up a MiniDSP before and it was very sensitive to outlet grounding. When playing around again in a different system there was the usual buzzing and humming. Could it ever be bad to ground all the chassis's together and then to the outlet they are all connected to ?


By "all" the chassis's i mean MiniDSP, behringer amp, subwoofer plate amps(2) ect

 

[Bill Fitzmaurice]



Quote:
Originally Posted by kgveteran  /t/1517768/is-common-chassis-grounding-ever-bad#post_24356009


Could it ever be bad to ground all the chassis's together and then to the outlet they are all connected to ?

Yes. Multiple ground paths can cause ground loops. That's why these exist:
http://www.americanmusical.com/Item--i-DAN-HUMFREE

 

[kgveteran]

So, whats the best procedure to eliminate the hum and buzz........

 

[pgwalsh]



Quote:
Originally Posted by Bill Fitzmaurice  /t/1517768/is-common-chassis-grounding-ever-bad#post_24356089


Yes. Multiple ground paths can cause ground loops. That's why these exist:
http://www.americanmusical.com/Item--i-DAN-HUMFREE

A question on top of a question.


If you have multiple amps running to multiple circuit breakers will this cause any issues? I haven't had any, but I was wondering if issues could arise. My assumption is no as long as they're all going to the same breaker box, but curious. So you don't use the grounding lugs if the main circuit is grounded?

 

[Bill Fitzmaurice]



Quote:
Originally Posted by pgwalsh  /t/1517768/is-common-chassis-grounding-ever-bad#post_24356609


If you have multiple amps running to multiple circuit breakers will this cause any issues? I haven't had any, but I was wondering if issues could arise. My assumption is no as long as they're all going to the same breaker box, but curious. So you don't use the grounding lugs if the main circuit is grounded?

This explains ground lops in detail. With pro gear they're very easy to eliminate, as the signal and power ground paths aren't shared with well designed gear using balanced transmission. Consumer unbalanced gear is a ground loop waiting to happen, and can be a real chore to get rid of.
http://www.rane.com/note110.html

 

[Trepidati0n]



Quote:
Originally Posted by Bill Fitzmaurice  /t/1517768/is-common-chassis-grounding-ever-bad#post_24356629


This explains ground lops in detail. With pro gear they're very easy to eliminate, as the signal and power ground paths aren't shared with well designed gear using balanced transmission. Consumer unbalanced gear is a ground loop waiting to happen, and can be a real chore to get rid of.
http://www.rane.com/note110.html

I wouldn't say that Progear "eliminates" it but it manages it in such a way that it becomes a non-contributing factor the accurate reproduction of the source signal. Unless you have a transformer in the signal path, it is flat out there. Now with differential inputs you can "subtract" out the common mode but it isn't like the common mode went on vacation. However, given a ****** enough situation, I can, without doubt, make Progear "not work".


Simply put:


Consumer gear = more work for hum

Pro gear = less work for hum

 

[J_Palmer_Cass]



Quote:
Originally Posted by kgveteran  /t/1517768/is-common-chassis-grounding-ever-bad#post_24356009


So, I've hooked up a MiniDSP before and it was very sensitive to outlet grounding. When playing around again in a different system there was the usual buzzing and humming. Could it ever be bad to ground all the chassis's together and then to the outlet they are all connected to ?


By "all" the chassis's i mean MiniDSP, behringer amp, subwoofer plate amps(2) ect

Are most chassis grounded or are they floating?

 

[a|F]

Does running my power cords near speaker cables or hdmi contribute to ground hum? I finally got the minidsp and cable box to stop the dreaded hum, but now I added a projector and it seems to have flaired up again...

 

[Trepidati0n]



Quote:
Originally Posted by J_Palmer_Cass  /t/1517768/is-common-chassis-grounding-ever-bad#post_24356960


Are most chassis grounded or are they floating?

Depends on what they had to do to meet UL/CE requirements. If there is no reasonable way to come in contact with voltage potential with enough current to kill you..it probably won't have it. However, Progear will have it regardless because of the very reasons the link that Bill F shows. They know that common-mode is a non-trivial probability and they choose to deal with it up front.

Quote:
Originally Posted by a|F  /t/1517768/is-common-chassis-grounding-ever-bad#post_24357000


Does running my power cords near speaker cables or hdmi contribute to ground hum?

In mathematical theory...yes. In reality, highly unlikely. For 50/60 Hz to couple via radiation requires a hell of a signal. But, the MiniDSP should be on the same power strip as the AVR or PreAmp if the output is not "balanced".

 

[Bill Fitzmaurice]



Quote:
Originally Posted by a|F  /t/1517768/is-common-chassis-grounding-ever-bad#post_24357000


Does running my power cords near speaker cables or hdmi contribute to ground hum?

Perhaps, if they're touching each other over a run of a few yards. But it would be unusual.

Quote:
I finally got the minidsp and cable box to stop the dreaded hum, but now I added a projector and it seems to have flaired up again...

That means that the projector is the culprit.

 

[kgveteran]

So, last piece of gear added that makes the system hum is the culprit......

 

[noah katz]



Quote:
Originally Posted by Bill Fitzmaurice  /t/1517768/is-common-chassis-grounding-ever-bad/0_50#post_24356089


Yes. Multiple ground paths can cause ground loops. That's why these exist:
http://www.americanmusical.com/Item--i-DAN-HUMFREE

Good to know about those, thanks for the link.


Unfortunately they're only offered with Ground Delivery.

 

[kiwi2]

Try using an off cut of speaker wire to ground the chassis of the DSP with amp or preamp and see if that makes the problem better or worse.