ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 ... 3 4 [5] 6 7   Go Down

Author Topic: Current model JBL SRX boxes induce buzz in mic cables/channels  (Read 3065 times)

Michael Kofei

  • Newbie
  • *
  • Offline Offline
  • Posts: 14
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #40 on: September 28, 2018, 12:01:06 pm »

Are you absolutely sure there is nothing else going on with the AC in the building?

This ^ is what I was going to suggest as well.

Sounds like you have an electrical power issue — in the wall/building. It just doesn’t make sense to me that all of your mic cables that apparently worked flawlessly are now failing, nor that JBL made a shit PSU and no one until now discovered it.
Logged

Dave Garoutte

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1233
  • San Rafael, CA
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #41 on: September 28, 2018, 12:37:47 pm »

I had an intermittent buzz happening in my bass preamp for a while.
I sent it back to the (local) manufacturer to check out.
They found nothing, but it kept buzzing.
I finally realized it was coming from the high tension wires passing over my shop when the humidity was high.
BzzZZP.
Logged
Nothing can be made idiot-proof; only idiot resistant.

Events.  Stage, PA, Lighting and Backline rentals.
Chauvet dealer.
Inventor.

Adam Kane

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 65
  • Battle Creek, MI
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #42 on: September 28, 2018, 02:02:53 pm »

This ^ is what I was going to suggest as well.

Sounds like you have an electrical power issue — in the wall/building. It just doesn’t make sense to me that all of your mic cables that apparently worked flawlessly are now failing, nor that JBL made a shit PSU and no one until now discovered it.

I believe Greg stated earlier in the thread that this problem has been present in more than 1 venue and power system (distro vs no distro, etc).
Logged

Greg_Cameron

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 662
    • Cameron Pro Audio
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #43 on: September 28, 2018, 04:21:45 pm »

It seems ridiculous to have to move from the Whirlwind cables to the star-quad.
Are you absolutely sure there is nothing else going on with the AC in the building?
Have you tried duplicating the problem in a different building?
Just for kicks, I would put a ground lift adapter on the AC cord feeding the buzzing JBL just to be sure it isn't some type of ground loop.


Yeah, if you read back through the posts, you'll see I had this happen in more than one location. My first suspicion it was the JBL boxes causing it was back in August at an outdoor stage. Completely different AC supply and location. Buzz cleared when I pulled the plug on one of my wedges. As far as ground lifting the AC on the noise source speaker, I could give that a go. There's no ground loop per se since there's no signal cable plugged not the JBL. I figure if there was some other noise source coming up the ground wire from the AC supply, it would be present as well when plugging into the EV speaker with the same power cord pulled from the JBL in the first video.


Greg
Logged
"Procrastinators of the world - contemplate uniting!"

Cameron Pro Audio

Greg_Cameron

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 662
    • Cameron Pro Audio
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #44 on: October 11, 2018, 05:58:02 pm »

Update:


Got a shielded power cord to test. Didn't appear to make a difference which would lead me to believe the noise is living on the ground bus. Looks like new mic cables is the only solution at this time aside from replacing the speakers.


Greg
Logged
"Procrastinators of the world - contemplate uniting!"

Cameron Pro Audio

Debbie Dunkley

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4170
  • Central North Carolina
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #45 on: October 11, 2018, 10:23:40 pm »

Update:


Got a shielded power cord to test. Didn't appear to make a difference which would lead me to believe the noise is living on the ground bus. Looks like new mic cables is the only solution at this time aside from replacing the speakers.


Greg

Sorry to hear that Greg. Did you hear back from JBL ?
Logged
A young child says to his mother, "Mom, when I grow up I'm going to be a musician." She replies, "Well honey, you know you can't do both."

Adam Kane

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 65
  • Battle Creek, MI
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #46 on: October 12, 2018, 11:45:32 am »

Seems to m that there may have just been a (possibly) small run of these things that have this issue since this doesn't look to be widespread. I'd be demanding that JBL take these back and fix/replace them. The mic cables you're using now are no joke, and you shouldn't need to replace them or pay so much attention to placement just to be able to make it through a show.
Logged

Dan Mortensen

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 482
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #47 on: October 12, 2018, 11:48:48 am »

To be clear about this, the "Pin 1 Problem" has nothing to do with loops and everything to do with the path to ground on device input connectors.

Neil Muncy (R.I.P.) discovered that devices using foil traces to connect pin 1 to ground had buzzes occur when the RF induced upon cable shields exceeded some random amount. The foil traces, not being very robust in mass(?) diameter(?) compared to an actual wire, would act as resistors and not immediately dissipate all the RF to ground. Instead the RF would get into the circuitry of the mixer/power amp/whatever that the input was feeding.

Replacing the foil trace with an actual wire of even modest size eliminated the problem, as does making the foil trace be huge enough in width rather than skinny.

Not sure how relevant this is to your problem, but that detail should be stated correctly and I hope this is closer to correct.

It's encouraging but still troubling that quad cable clears up the problem.

My money is on unannounced value engineering of the power supply. Anyone else with new boxes?
Logged

Andrew Broughton

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1287
    • Check Check One Two
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #48 on: October 12, 2018, 12:32:05 pm »

You and Debbie should exchange amp photos and date/model/serial info to figure out if it's something in a specific manufacturing run. Did you buy them all together? Are the serial numbers close? Can you get another one of your boxes from a local supplier to test and see if you reproduce the issue with a box other than your own, from a different manufacturing run (earlier or later, or both if possible!).
These things will tell you whether it's a manufacturing defect, and the key to having JBL replace them. If others don't have this issue, you definitely should not rest until JBL fixes them. (for free)
Logged
-Andy

"Well, my days of not taking you seriously are certainly coming to a middle..."

http://www.checkcheckonetwo.com
Saving lives through Digital Audio, Programming and Electronics.

Art Welter

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1432
Re: Current model JBL SRX boxes induce buzz in mic cables/channels
« Reply #49 on: October 12, 2018, 02:48:55 pm »

If others don't have this issue, you definitely should not rest until JBL fixes them. (for free)
Sounds like a guarantee for "no rest" ;^).
Logged
Pages: 1 ... 3 4 [5] 6 7   Go Up
 


Page created in 0.06 seconds with 23 queries.