Noisy Quad PCI audio
Hey guys, I am running an 800mhz VIA ITX Board and a quad pci card. The board is 2004 vintage. I have a distinct noise on TX audio both through my node and remote base. I have shielded cables to both remotes, I have replace the power supply and greatly reduced the high pitch noise. An interesting note: the tx audio port is quiet when first booting the node pc. Once asterisk is running the noise returns. Has anyone seen this before? Do I have a bad main board or did I miss something else.. Thanks for your help! 73, Ron - N6GKJ 73, Ron - N6GKJ Sent from Yahoo! Mail on Android
I went chasing something similar last month with a URI. I was experiencing a high pitched whine on TX audio. I had a spare URI so I swapped them and the problem cleared up. I sent the URI back to DMK who replaced it at no charge and they are investigating the source at this time. N5ZUA ----- Original Message ----- From: Ron Simpson To: APP_RPT Mail List Sent: Tuesday, January 24, 2012 1:08 PM Subject: [App_rpt-users] Noisy Quad PCI audio Hey guys, I am running an 800mhz VIA ITX Board and a quad pci card. The board is 2004 vintage. I have a distinct noise on TX audio both through my node and remote base. I have shielded cables to both remotes, I have replace the power supply and greatly reduced the high pitch noise. An interesting note: the tx audio port is quiet when first booting the node pc. Once asterisk is running the noise returns. Has anyone seen this before? Do I have a bad main board or did I miss something else.. Thanks for your help! 73, Ron - N6GKJ 73, Ron - N6GKJ Sent from Yahoo! Mail on Android ------------------------------------------------------------------------------ _______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
I've had issues like that before with those VIA boards - it wasn't running the PCI card (it was [past tense] actually an IRLP node)... I never did succeed at eliminating the noise - even swapping the power supply didn't change much. Just having the PC hooked up to the contoller was enough for the noise to appear - I didn't even need to bridge the audio over. 73 - Jeremy, KD0EAV On 01/24/12 13:08, Ron Simpson wrote:
Hey guys,
I am running an 800mhz VIA ITX Board and a quad pci card. The board is 2004 vintage. I have a distinct noise on TX audio both through my node and remote base. I have shielded cables to both remotes, I have replace the power supply and greatly reduced the high pitch noise.
An interesting note: the tx audio port is quiet when first booting the node pc. Once asterisk is running the noise returns.
Has anyone seen this before? Do I have a bad main board or did I miss something else..
Thanks for your help!
73,
Ron - N6GKJ
73,
Ron - N6GKJ Sent from Yahoo! Mail on Android
_______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
I guess you could always apply a 1:1 600 Ohm isolation transformer. You can even get one of those at Radio Shack (still). JIM Date: Tue, 24 Jan 2012 13:44:52 -0600 From: kd0eav@gmail.com To: app_rpt-users@ohnosec.org Subject: Re: [App_rpt-users] Noisy Quad PCI audio I've had issues like that before with those VIA boards - it wasn't running the PCI card (it was [past tense] actually an IRLP node)... I never did succeed at eliminating the noise - even swapping the power supply didn't change much. Just having the PC hooked up to the contoller was enough for the noise to appear - I didn't even need to bridge the audio over. 73 - Jeremy, KD0EAV On 01/24/12 13:08, Ron Simpson wrote: Hey guys, I am running an 800mhz VIA ITX Board and a quad pci card. The board is 2004 vintage. I have a distinct noise on TX audio both through my node and remote base. I have shielded cables to both remotes, I have replace the power supply and greatly reduced the high pitch noise. An interesting note: the tx audio port is quiet when first booting the node pc. Once asterisk is running the noise returns. Has anyone seen this before? Do I have a bad main board or did I miss something else.. Thanks for your help! 73, Ron - N6GKJ 73, Ron - N6GKJ Sent from Yahoo! Mail on Android _______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users _______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
On 1/24/12 2:46 PM, Jim Duuuude wrote:
I guess you could always apply a 1:1 600 Ohm isolation transformer. You can even get one of those at Radio Shack (still).
Keeping unbalanced audio or other signal paths clean is such a pain... Isolation xfmrs are a good thing. If cellphone shack doesn't have them...IIRC Mouser, Digikey, even Broadcast Supply Warehouse, and some ham bits-and-pieces places (there are still a few left...) will. They should NOT be expensive, nor massive (like the old Weco 666 repeater coils...). I bought a box of them a couple years ago when I was building my streaming radio station, and, even between balanced audio sources and my console, I dropped them in on the back of my patch panel...just in case (and the audio chain meets the old FM proof of performance specs, so...). Basically you are more prone to have noise issues if you have multiple pieces of equipment where the grounds are at different voltage potentials between different pieces of equipment (like being plugged into different wall outlets or power strips). Don't discount the noise that switching supplies or wall warts can spew onto lines, nor noisy muffin fans on amplifiers (have this problem on a Henry amp right now), florescent lights, HT chargers...the list is long where it could be coming from, not to mention a/d device issues. -- Bryan In this world, you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant. You may quote me. Sent from my MacBook Pro.
Also Check for Ground Loops between chassis connections. And look for DC riding on the audio leads as well. And like Jim said use a 1:1 transformer on the audio leads if you cannot isolate it. -- Thanks in Advance Bob Brown, WØNQX Kansas City Metro Area http://sm0kenet.net http://byrg.net http://kcdstar.byrg.net http://w0nqx.blogspot.com Quis custodiet ipsos custodes? Its not how many watts you have, its the SIZE of your watts that matter! -- Johnny Marshall, W0JM-SK -- On Tue, Jan 24, 2012 at 1:08 PM, Ron Simpson <n6gkj.cm98@yahoo.com> wrote:
Hey guys,
I am running an 800mhz VIA ITX Board and a quad pci card. The board is 2004 vintage. I have a distinct noise on TX audio both through my node and remote base. I have shielded cables to both remotes, I have replace the power supply and greatly reduced the high pitch noise.
An interesting note: the tx audio port is quiet when first booting the node pc. Once asterisk is running the noise returns.
Has anyone seen this before? Do I have a bad main board or did I miss something else..
Thanks for your help!
73,
Ron - N6GKJ
73,
Ron - N6GKJ Sent from Yahoo! Mail on Android
_______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
participants (6)
-
"Jeremy R. Geeo [KDØEAV]" -
Bob Brown - WØNQX -
Bryan D. Boyle -
Jim Duuuude -
Ron Simpson -
Steve Agee