[mythtv-users] Impedance mismatch? -- Resolved

[Dick Steffens]

On 03/04/2015 10:17 PM, Gary Buhrmaster wrote:
> On Thu, Mar 5, 2015 at 5:44 AM, Dick Steffens <dick at dicksteffens.com> wrote:
>> T... Is this likely an impedance mismatch or could
>> it be some other issue with the Blu-ray player?
> Off the top of my head, it could also be a ground loop.  Could
> also be the power levels.  Could also be your PCs audio device
> is noisy/broken (they are not always well shielded).

I've never tried connecting any other device to the computer's line in, 
so I don't know if that is an issue or not. The line out is clean, though.

> Could
> also be your BluRay player's line-out is noisy.  Only a good
> signal analyzer and other test equipment is going to tell you
> for sure.
>
> I do not suppose you tried plugging the BluRay directly
> into your stereo to see if that sounds good, did you?

Using the cheap test equipment route, I just tried plugging the Blu-ray 
into the tuner jacks on the stereo. Works great. The other noise is 
gone. I'll leave it at that.

> I will also note that some TV's come with audio out
> (after decode), which can be plugged into a stereos
> aux (or line) inputs (and sometimes the output is source
> digital, which would have to be decoded for an old
> school stereo without a built-in decoder).

This TV, a Panasonic TC42PX14, has a Digital Audio Out, which I assume 
to be spdif. My Kenwood amplifier is from the 1970s, and so it is from 
before optical connections were available on consumer devices -- maybe 
even before optical connections were used in a lab. There are no analog 
outputs on the TV.

The Kenwood amplifier also has no remote control. The reason I was 
trying to use the line in on the computer was so that I wouldn't have to 
switch the input on the amplifier. On the other hand, if I'm going to 
use the Blu-ray player, I need to go over there and put the disc in the 
drawer, so I don't really need a remote to switch the amplifier from Aux 
to Tuner.

So, I'm going to call this one resolved.

Thanks to all of the rest of you who replied with ground loop and/or 
other recommendations.

-- 
Regards,

Dick Steffens