Onkyo TX-SR805 causing lights to flicker

[fightinkraut]

I moved into a new house last year and noticed that whenever I turn on my receiver the lights in the LR (where the receiver is located), DR, and Kitchen all flicker twice while the receiver clicks on. I've never noticed a problem while playing anything, just curious to know if you all think it could be a wiring issue and how I could test for potential problems.

Thanks for your help!

 

[bandphan]

Did you check to see if they are on the same circuit?

 

[fightinkraut]

Did you check to see if they are on the same circuit?

I haven't, but I assumed as much. My concern truly lies with the fact any lights are flickering at all.

On a possibly related note, the lights flicker in the bedroom when my wife turns on her hair dryer.

Highly suspect...

 

[bandphan]

Sounds like you have some load issues(no pun intended in the bathroom). See if you have room to install additional breakers. Check to confirm that the lights and HT gear or on the same circuit. And then consider calling a electrician to add breaker/s and move the load around.

 

[fightinkraut]

Sounds like you have some load issues(no pun intended in the bathroom). See if you have room to install additional breakers. Check to confirm that the lights and HT gear or on the same circuit. And then consider calling a electrician to add breaker/s and move the load around.

Sounds like a plan. I did some reading on installing a breaker myself...think I'll pass on that one. I enjoy working with wood, metal, etc...specifically things that don't readily kill if you touch them with the wrong tool.

I'll post back tomorrow night after checking on the lights/HT gear.

Thanks!

 

[bandphan]

I dont mind low voltage, I just dont like playing with electricity (especially if its someone else's work) Rickster71 would be a good person to PM about this.

 

[PENG]

The Onkyo has quite a large power supply transformer. When you switch on a power transformer, you may incur an inrush current of 12 to 20 times of the full load current (could be higher but rare) for a short duration, say up to 0.1 second. This is the case under no load condition, even if nothing is connected to the secondary winding of the transformer. Such high inrush current is enough to cause your light to dim due to excessive voltage drop, and can be normal in many cases. The inrush current can be lower or higher, depending on when the load is switched on (know as point on wave). If the voltage wave happens to be just rising from zero when you turn on the unit, you will incur the highest inrush current while if you switch it on when the voltage sine wave peaks (at 90 degree) the inrush current will be lower (minimum)

When you first turned on the motor it behaves like a transformer under no load condition so the inrush current will also be high, say 6 to 10 times its full load current depending on the type and size of the motor. As the motor spins up to speed it produces a counter emf that opposes the incoming voltage hence lowering the current. That's why it also causes your light to go dim due to the initial high current that results in voltage drop; and then the voltage recovers as the motor gets up to full speed, so the light goes bright again, hence the flicker.

If your lights dim too much, it would indicate that your outlet may be too far away from the breaker panel. The longer the cable run the more the voltage drop. The voltage drop is proportional to the magnitude of the current and the impedance of the cable. So yes, to minimize light flicker or dimming, and most importantly losing power output on you amp, use shorter run and larger size wire.

 

[fightinkraut]

The Onkyo has quite a large power supply transformer. When you switch on a power transformer, you may incur an inrush current of 12 to 20 times of the full load current (could be higher but rare) for a short duration, say up to 0.1 second. This is the case under no load condition, even if nothing is connected to the secondary winding of the transformer. Such high inrush current is enough to cause your light to dim due to excessive voltage drop, and can be normal in many cases. The inrush current can be lower or higher, depending on when the load is switched on (know as point on wave). If the voltage wave happens to be just rising from zero when you turn on the unit, you will incur the highest inrush current while if you switch it on when the voltage sine wave peaks (at 90 degree) the inrush current will be lower (minimum)

When you first turned on the motor it behaves like a transformer under no load condition so the inrush current will also be high, say 6 to 10 times its full load current depending on the type and size of the motor. As the motor spins up to speed it produces a counter emf that opposes the incoming voltage hence lowering the current. That's why it also causes your light to go dim due to the initial high current that results in voltage drop; and then the voltage recovers as the motor gets up to full speed, so the light goes bright again, hence the flicker.

If your lights dim too much, it would indicate that your outlet may be too far away from the breaker panel. The longer the cable run the more the voltage drop. The voltage drop is proportional to the magnitude of the current and the impedance of the cable. So yes, to minimize light flicker or dimming, and most importantly losing power output on you amp, use shorter run and larger size wire.

I can't say I understand all of that, but it's good to know! I haven't had a chance to check the breaker box yet, but as far as location, it is about as far away as possible.

I'll selectively pick your suggestion to use larger size wire as a recommendation to use esoteric power cables, eh?

One thing I just thought of, I should try plugging the Onkyo directly into the outlet and see if I'm getting the same result, right now it's running through a surge protector. Methinks that could potentially cause a problem, yes?

 

[Porkys]

Yes it is the fact that u don't have enough power coming in compared to the power you are using
i own a hvac company and if a person installs a refer unit on like a 100 amp service there is a good chance that anytime the compressor kicks in the lights will dim
what is happening is that anything that consumes alot of power to start sucks electric from other sources just while starting after it is running it consumes less electric to run

 

[PENG]

I can't say I understand all of that, but it's good to know! I haven't had a chance to check the breaker box yet, but as far as location, it is about as far away as possible.

I'll selectively pick your suggestion to use larger size wire as a recommendation to use esoteric power cables, eh?

One thing I just thought of, I should try plugging the Onkyo directly into the outlet and see if I'm getting the same result, right now it's running through a surge protector. Methinks that could potentially cause a problem, yes?

I know that you knew I was talking about the feeder cable from the breaker panel box to the outlet. You want that cable to be as short as possible. For a 15A circuit people typically use AWG 14 and for 20A circuit AWG 12. Again, for somethiing like the 805 it is normal to see the lights dim a little when you first turn it on due to transformer inrush current. If you want to find simpler explanation of inrush current try googling related topics.

 

[PENG]

what is happening is that anything that consumes alot of power to start sucks electric from other sources just while starting after it is running it consumes less electric to run

If you are referring to things like motors, transformers, that do not typically suck a lot of power to start. They suck a lot of current but not power because on start up the power factor is typically very low. Power=Voltage X Current X Power factor. You can have the motor uncoupled from the load so it starts under no load condition, the lights on the same circuit will still dim because of the voltage drop caused by the high current draw.

When the compressor first kicks in it draws much higher current than it's rated full load current. That causes a lot of voltage drop so the lights dim for that reason. As soon as the compressor runs up to full speed the current draw will fall back to normal and the light should brighten up.

On another note, you can have a 400A panel, but if you run a 200 feet AWG14 to an outlet at the far corner of your house you will have so much voltage drop that will make it prone to light dimming if like you say you have a few thing sucking current from that circuit. In that scenario you don't even have to overload the circuit to have light dimming.

 

[ParadigmDawg]

Just for the record, my lights dim when I plug in the iron.

It has always struck me as strange, I can turn on my system which has 4 amps, a display, SMS-1 and cable box and the lights don't dim.

The lights don't dim when all the pool equipment kick on but yet the little iron makes them dim.

My solution was to just take everything to the drycleaners....