[EDS_]

Vizio P42HDe plasma
Adcom GFP-750 preamp
Llano Trinity 300 hybrid amp


When the TV and preamp are on the preamp "vibrates" @maybe 35 db.
When the TV, preamp and amp are on the preamp and the amp vibrate only the amp vibrates @maybe 40db.
When the TV is on and the preamp is off the amp still "vibrates".
These vibrations are not constant.......they fade in and fade out.

The speaker output seems perfectly normal.

All buzzing stops when the TV is off.

Is the TV dumping trashy A/C noise into my lines?

WTF?

[zachslc]

Solution:  Ship plasma TV to me.  Problem solved.

Sounds like DC on the lines, not AC, if the buzzing is intermittent.  It is probably coming froom the big toroids.  DC blocking modules are easy to install in the amps.  I used one made by LC audio for simplicity, but they can also be done DIY.  There was a discussion about this on the AKSA board not too long ago.

Could someone with more expertise weigh in?

[John Casler]

Had the same problem with a Panny 50" once, and a 99 cent cheater on the Panny AC cord solved the problem.  (no guarrantee, but it's worth a try)

[EDS_]

Had the same problem with a Panny 50" once, and a 99 cent cheater on the Panny AC cord solved the problem.  (no guarrantee, but it's worth a try)

Hi John:
I tried a cheater plug. I did not help. It was a good idea. Thank you.
If the preamp is plugged in but turned off the TV still causes the preamp to buzz/humm.

[John Casler]

Had the same problem with a Panny 50" once, and a 99 cent cheater on the Panny AC cord solved the problem.  (no guarrantee, but it's worth a try)

Hi John:
I tried a cheater plug. I did not help. It was a good idea. Thank you.
If the preamp is plugged in but turned off the TV still causes the preamp to buzz/humm.

Boy that is interesting

How can the preamp "hum/buzz" if it is off?

Many of the Plasmas have noisy tranformers, so I thought that might be your problem.

Your next best guess would then be your cable/sat grounding.  If you unhook the cable/sat from the wall, unplug the cable sat from the AC wall plug, and unhook the cable/sat interconnects from the system, does it still hum?

[EDS_]

Boy that is interesting

How can the preamp "hum/buzz" if it is off?

Many of the Plasmas have noisy tranformers, so I thought that might be your problem.

Your next best guess would then be your cable/sat grounding.  If you unhook the cable/sat from the wall, unplug the cable sat from the AC wall plug, and unhook the cable/sat interconnects from the system, does it still hum?

Hi John:
I think the TV is somehow sending trash back into my lines. If I power the TV through an extension cord plugged into another circuit the problem goes away.

BTW-the palsma does generate some mechanical hum of it's own (I can hear this comming from the back of the set)..................these issuse must be strongly related.


I'm totally nude in the power conditioning department. That fact may have to change.