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Discussion Starter · #1 ·
Used two 75-300ohm balins spliced back to back from radioshack to rid my speakers of the wicked hum the cable coax caused a few years back. That worked great for the cable tv coax but last night when I finally hooked up the Hughs E86 to my Tv it all returned. These two Balins wont pass the signal to the hughs. The installer said voltage needs to pass on that coax as well and he had no answers either. My dvd uses component straight to the TV and a digital coax to the pre/amp for sound.To get the system going I had to switch the digital coax to a tos link and lose the svideo (pre/amp OSD)from the pre/amp to the Tv and that basically took away the satellites ground path from my tv to dvd to pre/amp to the amps etc. The hum is gone but this is only a temporary fix as I want to go back to digital coax, svideo for pre/amp OSD and eventually component switching. Anybody know how to get rid of the hum coming from the satellite coax ? The satellite & house wiring are well grounded as well. Any help would be much appreciated, some installers somewhere had to face this problem before.


Regards

Shaun
 

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I would look at how (and where your sat and power systems are grounded. The fact that they are both grounded is no good if they are not grounded so that they are at the same potential. This means at the same ground point. I had a differnet ground for the lightning blocks vs the power ground and had hum to beat the band. As soon as I grounded the blocks to the same ground as house power, the problem went away.

Check to see that all grounds are at the same potential.


Sim
 

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Hum doesn't exactly come from the satellite coax. It is picked up by a ground loop that is formed by the satellite coax and something else. You need to find that something else and put a ground loop isolator on it if possible.


Does this system incorporate cable TV? If so, try putting your back-to-back matching baluns on your cable line at a point after it passes its entry ground. You might also put a matching balun isolator on your off-air antenna line.
 

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Does the Hughes E86 have a 3-prong plug? Are you using a surge suppressor or power strip?


You might try a 3-to-2 prong A/C adapter (about $1.50 at Home Depot) to eliminate the ground pin of that plug.


My experience with connecting lots of boxes in an entertainment system with the myriad A/V cables, and then also having more than one 3-prong A/C power plug inserted into 3-prong power receptacles is that this can easily be a source for ground loop hum. There really shouldn't be more than one 3-prong plug device, as an excellent approach to eliminating a possible source of ground loop hum.


Isolating the ground pin on my Threshold T200 power amplifier using such an adapter completely eliminated the hum which was present in my many-device entertainment system. All my other devices were 2-prong phased or unphased plugs, leaving only my Threshold T2 preamp as the one 3-prong plug in the system.
 

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Discussion Starter · #5 ·
Quote:
Originally posted by DSperber
Does the Hughes E86 have a 3-prong plug? Are you using a surge suppressor or power strip?


You might try a 3-to-2 prong A/C adapter (about $1.50 at Home Depot) to eliminate the ground pin of that plug.


My experience with connecting lots of boxes in an entertainment system with the myriad A/V cables, and then also having more than one 3-prong A/C power plug inserted into 3-prong power receptacles is that this can easily be a source for ground loop hum. There really shouldn't be more than one 3-prong plug device, as an excellent approach to eliminating a possible source of ground loop hum.


Isolating the ground pin on my Threshold T200 power amplifier using such an adapter completely eliminated the hum which was present in my many-device entertainment system. All my other devices were 2-prong phased or unphased plugs, leaving only my Threshold T2 preamp as the one 3-prong plug in the system.
Thanks for the feedback guys, more the merrier..


DSperber,

I ran four dedicated 20amp circuits for HT last year, the only component with a three prong ground plug is my mccormack two channel amp. The hughs doesnt not have a ground prong and I'm using no line conditioners or surge protectors..Im wondering if the multi-switch behind the dish is faulty, who knows..Ill keep hacking away at it when the weekend arrives.


regards

Shaun
 

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Discussion Starter · #6 ·
Quote:
Originally posted by DSperber
Does the Hughes E86 have a 3-prong plug? Are you using a surge suppressor or power strip?


You might try a 3-to-2 prong A/C adapter (about $1.50 at Home Depot) to eliminate the ground pin of that plug.


My experience with connecting lots of boxes in an entertainment system with the myriad A/V cables, and then also having more than one 3-prong A/C power plug inserted into 3-prong power receptacles is that this can easily be a source for ground loop hum. There really shouldn't be more than one 3-prong plug device, as an excellent approach to eliminating a possible source of ground loop hum.


Isolating the ground pin on my Threshold T200 power amplifier using such an adapter completely eliminated the hum which was present in my many-device entertainment system. All my other devices were 2-prong phased or unphased plugs, leaving only my Threshold T2 preamp as the one 3-prong plug in the system.
Thanks DSperber,

That worked out great, the McCormack two ch amp was the culprit. Taking away the ground prong was the solution to the hum but this was the *only* component using one one. Now there is no components using ground prong, hope this configuration doesnt come back to haunt me one day.


regards

Shaun
 
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