Amplifier and Downstairs Lights

Restorer-john said what I had on my mind. The temporary dim means nothing. If it stayed dim, then you have a problem. If your circuit is 15 amp and uses 14ga wire, that may also cause the issue as the current cannot flow as easily through 14ga wire as it can through 12ga wire. This is also true for your speaker wire. If you have long run to your speaker and you use 20ga speaker wire, you are losing some of your signal to heat. In house wiring, if the run is over 100ft, you need to bump up to the next wire size and the same it true for speaker runs.

Unless your lights stay dim, you do not have a problem.
 
Speaker wire is pretty simple, 16ga with a 10ft avg length (amp to floor to floor to speaker). I don't have a ton of space.

Thank you to everyone who has given feedback. I feel more comfortable with my setup -- though I am going to have to do some more reading on why I get this flicker with an amp whose output is less than my previous amp. I am sure that there could be a couple of reasons with some far more likely than others.

I have checked the fuse box, and nothing has signs of corrosion or damage. I do have more testing to do on this particular plug -- it has only ever been used for stereo equipment. Thank you for the wall plug tester. I will go by a hardware store to pick on up.
 
The lights dim briefly. They return to normal. My hairdryer did the same thing on the same plug.

My old amp did not do this, and it was 105 watts/ channel instead of 70. Was it more efficient? I guess that is more for me to figure out. The current amp is about 4x as heavy as the old amp. I understand that weight does not equal power, but it sure feels like it.

The part about watts per channel doesn't really apply here too much. While it'll make a little difference, the numbers you'll want to look at or compare are the watts/amps that each pull from the wall.

Here's a Yamaha CR-1020:

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It's rated at something like 70ish watts per channel (I don't recall off the top of my head and I've owned mine for years), but if you look at the photo, it is rated 320 watts at 120V. That's the (max) power it should pull from the electrical outlet, or in amps, 390VA/120V=3.25amps.

When it's on and operating, at most it's pulling 3.25 amps of current from the wall. On a 30Amp circuit, you've got 26.75(or so) to spare before it's overloaded and trips.
 
Speaker wire is pretty simple, 16ga with a 10ft avg length (amp to floor to floor to speaker). I don't have a ton of space.

Thank you to everyone who has given feedback. I feel more comfortable with my setup -- though I am going to have to do some more reading on why I get this flicker with an amp whose output is less than my previous amp. I am sure that there could be a couple of reasons with some far more likely than others.

I have checked the fuse box, and nothing has signs of corrosion or damage. I do have more testing to do on this particular plug -- it has only ever been used for stereo equipment. Thank you for the wall plug tester. I will go by a hardware store to pick on up.

Either the new amp has higher inrush current or less inrush limiting, or the other amp had lower inrush current or stronger inrush limiting.

In either case the most likely scenario is that you are on a wild goose chase. Even if the receptacle tester was to reveal some reversed wires that won't change the inrush characteristics of the amp.

A better test, if you want to pursue something, would be a high load test.

Measure the voltage at the receptacle with no load applied. Then connect something like that hair drier or a heater that pulls 1000-1500 watts. Then with that load turned on, measure the voltage at the same receptacle. What is the loaded vs. unloaded reading?
 
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It's rated at something like 70ish watts per channel (I don't recall off the top of my head and I've owned mine for years), but if you look at the photo, it is rated 320 watts at 120V. That's the (max) power it should pull from the electrical outlet, or in amps, 390VA/120V=3.25amps.

When it's on and operating, at most it's pulling 3.25 amps of current from the wall. On a 30Amp circuit, you've got 26.75(or so) to spare before it's overloaded and trips.

Okay -- that makes sense. On the back of this one it lists the max at 5 amps -- but the numbers don't line up quite like yours. It lists 120VA, 60Hz, 5 amps, maximum all stacked on top of one another -- I need to do some reading to learn how the math works. I'll have to check my previous amp for interest.

I think that the wall plug will be the place to roll up my sleeves. I should be able to make the hardware store trip by the weekend.
 
Okay -- that makes sense. On the back of this one it lists the max at 5 amps -- but the numbers don't line up quite like yours. It lists 120VA, 60Hz, 5 amps, maximum all stacked on top of one another -- I need to do some reading to learn how the math works.

Don't waste too much time on it because there is little rhyme nor reason to it. People will cite a few rules or thumb and maybe even some theory how the specific number was determined, and that's fine. But, generally, for consumer gear nobody outside the mfg. really knows for sure what's behind any given back panel rating.

The back panel ratings are derived from conditions of the manufacturer's testing and regulatory certification requirements. The exact nature of the rating is not standardized between different manufacturers nor even necessarily for different models of the same brand. It is not an apples to apples way to compare things.

I like to cite the Yamaha M-80 as a good example. The service manual lists four or five widely different back panel ratings all for the same amp. The only difference is the testing and regulatory requirements for the intended market region.
 
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Okay -- that makes sense. On the back of this one it lists the max at 5 amps -- but the numbers don't line up quite like yours. It lists 120VA, 60Hz, 5 amps, maximum all stacked on top of one another -- I need to do some reading to learn how the math works. I'll have to check my previous amp for interest.

I think that the wall plug will be the place to roll up my sleeves. I should be able to make the hardware store trip by the weekend.

@120VA, and assuming you're on 120V grid electricity, the unit itself should draw about 1 Amp.

120VA / 120 V = 1 Amp

The 5 Amps maximum, is the max amount of current it can handle which is the sum of its own power needs, plus any electrical devices powered through it.

Imagine having five of this particular amp. According to that 5 Amp max number and the fact that each draws 1 Amp, you could theoretically daisy-chain four more, one plugged into the next, off the outlet on the back of the first. If you were to add a sixth, you would be increasing the load by 120VA, or 1 Amp, which would then overload the original amplifier by 1 Amp, probably tripping it's fuse/internal protection somewhere.

Your amplifier, which by itself only draws 1 Amp, is pulling roughly the same amount of current as two 60W incandescent light bulbs* - that's not really all that much.

* Yes light bulbs are a resistive load, and powering the amplifier on probably acts at least a little inductive while it charges up its capacitors thus drawing a bit more than that 1 Amp for a sec, but complicates the math more than it needs to be for the numbers we're working with.

All said and done, as long as you're sure you're not overloading the house circuit that your amplifier, equipment, and lights all share, it's probably fine that you get a quick dim of the lights as you power up the amplifier and nothing to really be concerned about.

Are your light bulbs regular incandescent? If so, you might consider switching to LED bulbs - you'd probably never see the dimming on power-up, and use less electricity to boot.
 
* Yes light bulbs are a resistive load, and powering the amplifier on probably acts at least a little inductive while it charges up its capacitors thus drawing a bit more than that 1 Amp for a sec, but complicates the math more than it needs to be for the numbers we're working with.

Unless the topic has changed from lights momentarily dimming on power up it is more complicated. One can work math all they want with the back panel rating but it doesn't tell you anything about inrush.
 
Just for interest (or not), domestic lighting and power circuits are separate in the UK, brief power surges causing momentary light dimming is seldom seen because of this.
 
Another consideration that no one has mentioned (so far) is the class of operation of the amplifier. Class A amplifiers demand far more current than a switching design. I have a quad of 4 Krell KMA 160 monoblocks that are 160w each @ 8 ohms, but "double down" to a power rating of 1280w each @ 1 ohm (from the owners manual), and each amp draws 8 amps at idle because they operate in pure Class A mode--and yes, you can cook eggs on them once they come up to temp at idle, so they will put any hair dryer to shame in terms of "sucking the wall socket dry". OTOH, there are Class A/B and Class D amps that produce as much (or more) power with far less draw--so design/topology is an important factor.
 
Just for interest (or not), domestic lighting and power circuits are separate in the UK, brief power surges causing momentary light dimming is seldom seen because of this.

Don't y'all use ring circuits too? That would seem to help as well since it's basically a parallel path or wiring to all the receptacles.
 
Yes we do - rings for 'downstairs power', 'upstairs power', 'downstairs lights', 'upstairs lights' and a separate ring for the kitchen usually with a dedicated line for the cooker/hob - well, that's how my house is wired. ;) - and all protected with combined MCB/RCD breakers.

And back on-topic.
However, if I have a desk light for example plugged into a power ring, I can detect a momentary dimming of that light when I turn on some of my amplifiers (not all), if plugged into the same ring.
 
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Another consideration that no one has mentioned (so far) is the class of operation of the amplifier. Class A amplifiers demand far more current than a switching design.

Indeed. However, I'd argue that class of operation isn't directly related to the OPs concern of inrush current causing momentary dimming of lights.

...each amp draws 8 amps at idle because they operate in pure Class A mode--and yes, you can cook eggs on them once they come up to temp at idle, so they will put any hair dryer to shame in terms of "sucking the wall socket dry".

Another indeed. 8A is quite a lot of idle current. However, on a per unit basis one hair dryer can handily exceed 8A draw; by more than 50% in this example, hence making a very good load test for a standard circuit. I do prefer the sound of Krell vs Conair though. ;)

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Welcome to the wonderful world of 120v AC house circuits (non-ring main wired). Where I live, small amps do it, the power supply for my soldering iron does it, and big amps make a big dip in the lights. When I put the kettle or toaster oven on when the microwave is running, you can hear the picture of the cooling fan drop. In the laundry room, the lights flicker like a haunted house when the washer is going. Similar things happened in the past two houses I lived in when I moved here.

Back in England, we had 240v, so half the current is drawn for the same power (wattage) load. Houses are also wired in what they call a ring main. A wire comes out from the fuse box, goes to all the outlets in a room, and then comes back to the fuse box, giving twice the amount of copper.

If it bothers you, you might want to install a dedicated outlet just for your HiFi equipment. If you don't have to (or don't want to) get it inspected, run two lengths of 12AWG from the outlet back to the fuse box.

Lee.
 
Look up and make a dim bulb tester. A normal startup for a DBT is for the bulb to start bright and then dim after a few seconds. This is a graphic depiction of what happens in your home wiring. The receiver/amp charges the caps first, which takes a large current draw. The dim bulb device will shine brightly and then dim. Your electrical system will do the opposite.

Also, if you are starting your device with the speaker switch applied, start a new start up/off procedure. Before you switch off your power button, switch off your speaker load. When starting up do the opposite, switch power on first and then switch on the speaker load. This may also alleviate some of the dimming that is happening.
 
I'd think speakers switched on/off wouldn't have too much impact on inrush. Exception might be if one turns on the amp with the volume knob turned up pretty high and a source already engaged for playback.
 
I had a Conair amp once. The volume could blow you away, but it ran hot, and the treble could best be described as hairy, almost like there was a lot of comb filtering going on.
Yes, I've experienced the same with what I believe to be a similar unit.

And can only describe it as an excessively "frizzy" effect if used to extreme.

Split ends were especially problematic, especially while actually listening to Split Enz. :dunno:
 
The amplifier is a bit noisy when it turns on, the noise seems to go away after it is warm, and there is a light noise (ear within 6 inches of the speaker) after it has powered off. For the last, I have systematically gone through all of my equipment to verify that the amp was making the noise. I don't know if any of these are additional red flags, but it has run this way since I got it.

Am I the only one that read this and thought that it might be time to replace the power filter caps?

Power inrush issues, maybe. More likely the caps have lost their ability to maintain most of their correct values of capacitance. The noise going away after the amp warms up and then the noise returning after powering down surely spells filter caps does it not?
 
I forget ... you say you've tried the amp on other circuits? That would help to pinpoint the problem.

Could also be a bad breaker that's ready to fail. Still on the old glass fuses here, but I had one that had arced somewhere along the way and there was some carbon and pitting in the fuse socket. That circuit had been blinking a bit. Polished that out, installed a new fuse, and nary a blip since.
 
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