AVS Forum banner
Status
Not open for further replies.
1 - 18 of 18 Posts

·
Registered
Joined
·
89 Posts
Discussion Starter · #1 ·
OK, now the questions relating to my new P50.


I hope there is an easy answer to this one.


I will be integrating the display into an audio system but wanted to connect a pair of small satellite speakers directly to the P50 so my wife and kids can "just turn on the TV" and have audio.


So I connected two speakers. They are just the right size and sit nicely right next to the display. I get sound, but there is a strong hissing sound. So far, my plan has been foiled by an unknown villain.


I have read about using ferrite cores (after I hooked it up of course), and the manual discussed using them. I then put them on the speaker line, but it didn't help. I'll try to loop the cable around the core to see if that makes a difference.


Is there another approach? Anyone know what the problem, and solution, is?


I am running a DirectTivo connected to the P50 via S video, with audio inputs also connected. DVD is also connected via component cables, no audio connected at the moment.


Many thanks.


RB
 

·
Registered
Joined
·
441 Posts
How about a little more info - what speakers do you have exactly hooked up. 10W output is not that much to drive speakers (other than the ones it was meant for and computer speakers).


Congrats on the purchase
 

·
Registered
Joined
·
21 Posts
A hiss could be caused by having too low a level coming out of your source, requiring the gain on the panel turned up high to get a reasonable sound level. By turning up the gain, you amplify the audio signal, as well as the noise.


Does your source have a standard output, or is it controllable. If its controllable, turn it up, and run a lower gain at the panel.
 

·
Moderator
Joined
·
23,039 Posts
RB,

I have the same setup. 2 small (old rear surrounds) speakers connected

to my P50, a DirectTivo, and cable stb. I use the P50 driven speakers

for all "regular" TV watching. I hear no hiss at all. You may have some

sort of "power problem" inducing the hiss. In the past I've had problems

will speaker hiss (not P50 connected) and were eliminated once

I hooked all my gear into power conditioners. Also, my P50 volume

is at "20".


sdm300 is correct too, but I don't recall doing anything on the DTivo

except connecting the L/R analog audio connectors into the P50.


And, I just thought of something. My speakers are most likely

shielded. Would unshielded speakers be affected by the P50 or

other gear?


larry
 

·
Registered
Joined
·
1,505 Posts
Maybe a ground loop problem with your sat coax cable. No easy way to test it though with that the only audio source connected to the PDP. Maybe hook up the audio r/l from the dvd player to see if they get the hum too? But this sat coax problem will only manifest itself from the DVD player if both the sat box and the dvd player are hooked together into a receiver.


But I would start by connecting the audio form the dvd to the PDP and see if it hums. If it does, then disconnect the sat coax from the sat box - disconnect it all the way. If that cures the hum, then its a ground loop problem. If its still there, then its something in the PDP or the speakers.


Good luck,


E. J.
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #6 ·
Thanks for the thoughts. Lets see if we can take this one step further.


Prof. Dave -- the speakers are a pair of Definitive Technologies ProCinema 80 speakers. I was wondering if there is enough power to drive them, but it seems to put out enough volume (sound and hiss). Specs on min power is 10W and I think there is 12W in the P50.


Steve -- I'll check the output, but I don't think there's anything adjustable on the DirecTivo.


Scooper (sorry I prefer that to Pooper) -- 1. What kind of power conditioners are you talking about? Right now I'm just plugged right into the wall. I need at least a surge protector. Any recommendations? I should buy this today! 2. What does "shielded" mean? I don't think this is the issue, see below.


ejfiii -- very interesting. Not tried a test yet, but you may be on to something. It seems I get the hiss through my regular speakers too (speakers which are connected through my stereo amplifier to which the DVD and Directivo audio outs are hooked up to) whenever something is hooked into the audio inputs on the P50. Even when no speakers are connected. I'll go do the test you describe -- hook the DVD audio into the panel, unhook the satellite coax to the Directivo, and see what happens.


RB
 

·
Registered
Joined
·
441 Posts
you know what you should do - Pick up a Harmony remote. They have a very family friendly one. It is activity based, all you do is push, watch TV and bam, everything comes on. I think that would be one solution. The solution to your problem is not curing the hiss, but making the volume family friendly.
 

·
Registered
Joined
·
1,505 Posts
Quote:
Originally posted by rbirnholz
It seems I get the hiss through my regular speakers too (speakers which are connected through my stereo amplifier to which the DVD and Directivo audio outs are hooked up to) whenever something is hooked into the audio inputs on the P50. Even when no speakers are connected. I'll go do the test you describe -- hook the DVD audio into the panel, unhook the satellite coax to the Directivo, and see what happens.
AHA! The plot thickens. Bet you a case of Krispy Kreme donuts that its a ground loop problem with the sat coax cable causing both problems.


Check this thread for a link to a VERY GOOD article on ground loops and how to cure them.


Best of luck.


E. J.
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #10 ·
ok, more info -- hiss is only from the Directivo audio output, whether into my stereo amp or the TV. DVD player plays fine through stereo amp OR the speakers hooked up to the plasma. (Could use some more power, but what the heck.)


Wierd thing is that the hiss from the Directivo audio output into the stereo amp is new, starting yesterday when the plasma arrived.
 

·
Registered
Joined
·
21 Posts
If you havent already, swap audio inputs to the plasma from dvd and dtivo. also can swap cables, to try to isolate the problem to the source, the cables, or the plasma.


dtivo is clean when hooked to stereo system?

also, try unplugging various unused components to try to isolate ground loops.
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #12 ·
Thanks again.


Not sure if this is comprehensive, but it seems like its something with the Directivo and the plasma.


DVD player played through plasma works fine. Directivo hisses.


I haven't tried every configuration, but it seems like there is a hiss through stereo or plasma attached speakers on only Directivo, whenever Directivo audio inputs are connected to the plasma.


Tried switching the plug for the Directivo to put it on the same plug outlet as the plasma. No difference.


Tried unplugging the stereo and DVD player, no difference.
 

·
Registered
Joined
·
1,505 Posts
But you didn't try to unplug the sat coax cable?
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #16 ·
I will try swapping L/R.


ejfiii -- if I unplug the sat coax then I won't have any sound.... The problem is coming from the DirecTivo only, and only when audio is connected to the TV.


If swapping left and right doesn't work, I'm going to try a ground loop isolator next.
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #17 ·
I think ejfiii wins the washer dryer.


I used a ground loop isolator for the audio from the Directivo. Hiss is gone.


Now should I try to solve the deeper problem, or did I by using the isolator cable?


Many thanks.
 

·
Registered
Joined
·
1,505 Posts
Hey hey, I think you jinxed me. I built my rack this weekend and upon powerup, I got a nasty buzz in the speakers for the first time. I know the cable is grounded properly, so I have to look at other possibilities.


I think if the isolator worked for you, I would be happy and call it a day.


You can PM me the washer/dryer - my wife is very excited. Please make it the new Duet unit. ;)


E. J.
 
1 - 18 of 18 Posts
Status
Not open for further replies.
Top