# Is a power surge coming through my speakers??!!



## ndurantz (Aug 10, 2008)

Twice now when I have used the universal remote to shut off the TV, receiver and my HDDVD/Blu-ray player simultaneously, I hear what I believe to be a power surge audibly over my speakers.

It sounds exactly like when "Boo" in _Monsters, Inc_. laughs and causes the blackout (if you don't know what scene I am talking about, do yourself a favor and rent _Monsters, Inc_. on Blu-ray - it is a brilliant film IMO).

I am freaked out that something is terribly wrong with my system and I am putting all my components in danger of being "fried." I do have everything hooked up through a Monster Cable surge protector, including the coax from the antenna.

Thoughts or helpful hints for trouble-shooting would be greatly appreciated. Have a great Friday!!


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## Dave Upton (Aug 4, 2009)

I would ensure that the receiver is shut off before any other component - often these 'burps' are audible when a component sends some sort of signal blip to your amp as it shuts down. Simply modifying the sequence should resolve this.


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## Syd26147 (Jul 4, 2008)

I also follow the last on/first off rule with all amps ( home and Pro Sound ).
Some line level devices are very bad at generating on/off transients that will get amplified otherwise.

Syd


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## ndurantz (Aug 10, 2008)

Syd26147 said:


> I also follow the last on/first off rule with all amps ( home and Pro Sound ).
> Some line level devices are very bad at generating on/off transients that will get amplified otherwise.
> 
> Syd


To make sure I understand, the reciever should be the first powered on and the last powered off in the sequence, which will not allow me to hear the "surge."

Should I be concerned there is a "surge" at all or is this fairly common and I don't need to worry?


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## tonyvdb (Sep 5, 2007)

Yes you are correct the receiver should be first on/last off if you have this issue.
Dont worry about it as this is very common particularly with large PA systems. The Bump sound is usually caused by the capacitors draining in the amplification section.


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## Syd26147 (Jul 4, 2008)

You got it flipped.
It's LastOn FirstOff ( LOFO ).
The final stage in an audio signal chain will take a signal approx. 1.5 volts and give it a final boost to a level to drive a speaker load ( approx 20 to 30X ).
The amp or receiver will amplify any voltage in the signal ( be it desired signal or undesired fast transient ).
Often a device ( in my case an active crossover ) will create these at start up and shut down.
If I power this on after the amp - POP, If I turn this off before amp power down - POP.
Most amplifiers have soft starts via relays to prevent it from being the source of a high voltage pop.
In the past I have linked some such events to the buildup/and collapse in the power supply circuits.
I'm sure you have hear audible pops and clicks come through sound systems as other electrical devices are turned on/off elsewhere on your home circuits.
By having the amp off at start up, no start up transients get through.
By turning it off 1st, no shut down transients get through 

Syd


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## ndurantz (Aug 10, 2008)

Syd26147 said:


> You got it flipped.
> It's LastOn FirstOff ( LOFO ).Syd


Glad you caught that! Makes total sense. I will get the sequence changes tonight and if not resolved, come back to see what else you all have in mind to try.

Thanks to everyone for their insight!


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## tonyvdb (Sep 5, 2007)

You will need to try different cycles. Given that the amp is the last peice of equipment in the chain before the speakers you may want to turn that off first. It really depends on where the "thump" is being generated.


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## JBL Fan (May 1, 2010)

What equip. do you have? Good quality amps and processors shouldn't thump or hiss or whatever...


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## ndurantz (Aug 10, 2008)

JBL Fan said:


> What equip. do you have? Good quality amps and processors shouldn't thump or hiss or whatever...


There really isn't a hiss, thump or pop. It is definitely a "power surge" type of sound. Is that type of sound referred to as a "thump" in audio circles? I think syd's explanation makes sense, but for WIW here is my set-up.

Source (for blu-ray & HD-DVD) - Samsung BD-UP5000 w/ digital coax out
Receiver - Onkyo HT-R550 (part of the Onkyo HT-SR800 HT system)
Speakers (5.1) - Orb Audio Mod 1's for all channels w/Super 8 sub (sub fed line out)


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