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tlee1 發表於 2010-11-20 22:40

ground loop in AV amp to Int. amp AV bypass

I'm using Yamaha 767 and front channel preout to AV bypass of Onix Int. amp.When I play AV system, both Onix and Yamaha turn on and there are a very little high frequency sound.It seems to be ground loop, any Ching can help?Thanks.

vicchow 發表於 2010-11-20 23:11

本帖最後由 vicchow 於 2010-11-20 23:12 編輯

回復 1# tlee1


    It is very strange. Most av-amp nowadays have ground pin removed already.

    Please verify if any other RCA connecting device has ground pin connected at the power cord.

    Also check other ground source like your antenna linked to HD TV box. if you use HDTV box, try to use the digital only connection interface like HDMI. becasue most of the digital circuit inside the AV-receiver is isolated from analogue output stage, so the ground loop issue will not happen if you use only the digital connection interface.

tlee1 發表於 2010-11-21 01:41

Thanks Vicchow Hing.I do have now tv and cable tv and dvd recorder connected to AV amp, but all connections to AV amp are by HDMI.The only RCA connection to AV amp is the front channel preout to Int. amp.But my now TV (also work as HDTV box) has RCA connection to my DVD recorder, is it the source of the problem?Please help.

tlee1 發表於 2010-11-21 20:34

Any Ching can help?

gurahamu 發表於 2010-11-21 21:40

本帖最後由 gurahamu 於 2010-11-21 21:41 編輯

I have had same problem. It was caused by my PS3 connected to a UK plug power bar while the rest of my gear connected to US plug. problem was resolved after all devices connected to US plug power bar.

tlee1 發表於 2010-11-21 22:36

本帖最後由 tlee1 於 2012-1-27 23:49 編輯

Thanks Gurahamu Hing, do you mean that all device input to AV amp should plug into the same power bar?

But I've tried all the 4 methods:
1. remove all (digital and analog) inputs, and even remove the HDMI to TV, only connected the speakers cable, preout RCA to int amp and sub-woofer cable to sub-woofer.
2. connected the case of the AV amp and Int amp
3. connected the case of AV amp to the "earth" of the power bar
4. remove the "earth" of the PC of the int amp

But the high frequency sound from the front speaker still exist and even no improvement, any CHing can help?

tlee1 發表於 2010-11-23 23:00

本帖最後由 tlee1 於 2011-12-31 14:17 編輯

Any Ching has the same experience can share?
{:1_347:}

gurahamu 發表於 2010-11-23 23:19

Thanks Gurahamu Hing, do you mean that all device input to AV amp should plug into the same power ba ...
tlee1 發表於 2010-11-21 22:36 http://www.post76.com/discuss/images/common/back.gif

Yes. FYI my AV amp was a Yamaha AZ2 (then changed to Marantz SR8002; both had same problem) connectedt via RCA OUT -> converter-> Balanced IN ->Jeff Rowland Concerto Integrated.

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