[mythtv-users] Audio - hiss (Buzz)

[Brian Wood]

On Mar 14, 2006, at 8:31 PM, Scott Croft wrote:

>
> I am using the same patch cord, and had tried another patch cord at  
> several
> points in this processes.
>
> I must have pluged and unpluged the cables about 100 times testing  
> different
> combinations, so I am reasonably sure that all was pluged in well.
>
> The patch cable is a 3 conductor cable with male mini-sterio  
> conectors on
> each end.  No conductivity (shorts) between any of the three wires or
> connectors as per my fluke meter.
>
> I am sure I had the patch cable ran into line in on the audio  
> card.  I also
> switched to the mic port while switching the mixer controls to look  
> for the
> input on that connection.  Same problem with the buzz on the mic as  
> with the
> line in as each was tested.  At one point I cut up a CD audio cable  
> and
> attached it to the aux audio port on the mother board and wired it  
> into a
> old sterio jack that I pluged into the line out on the TV card.   
> When I
> picked aux as the capture device and muted it I still got the buzz  
> along
> with the sterio tv audio signal.  The aux / CD inputs are a good  
> ways from
> the other audio input ports on the mother board.
>
> I really do not have any other ideas on how to fix this issue.   
> With the new
> PCI audio card I can use about any settings I want for volume on  
> the master
> or PCM and have no issues with any buzz.
>

Sure sounds like you have covered all the bases, I was just checking  
the more obvious ones.

The comment about a "ground loop" has merit, virtually any hum  
problem in AC-powered equipment can be traced to common-mode  
problems, but in truth I suspect the solution you have found, with a  
separate card, is probably easier to implement than finding and  
fixing grounding problems, you'll likely get better sound as well.

As long as you can spare the slot, I'd just go with that.