Amplifier and Downstairs Lights

welcomdmat

Super Member
Hi, all --

I have an amplifier that is 70 watts/ channel, but all of the lights on the same floor dim when I turn it on. I had not thought too much about it -- I have seen a hair dryer do the same thing in this house. Someone recently pointed it out to me, and the question has been floating around in my head. Could I be putting the rest of my system at risk, or is this just something that is fairly common?

Thanks!
 
You've got issues.

Might be time to consider adding a dedicated circuit for just the stereo. That's also a good way to isolate noise from all the other stuff running in the house. I did that here years ago.

Also be interesting to find out what you're running for service amps in the house. Most new construction is at least 200 amps, but I know my 80 year old converted cottage had the original 60 amp service from back in the day. That just wasn't gonna cut it in this day and age.
 
Hi, all --

I have an amplifier that is 70 watts/ channel, but all of the lights on the same floor dim when I turn it on. I had not thought too much about it -- I have seen a hair dryer do the same thing in this house. Someone recently pointed it out to me, and the question has been floating around in my head. Could I be putting the rest of my system at risk, or is this just something that is fairly common?

Thanks!

Hi welcomdmat,

Not sure what is causing the load of the house to drop, but I'd be carful running the amp unprotected. Invest in a nice surge protector for the time being. I'd reach out to PG&E, and/or your local electrical provider and request they send a tech out to troubleshoot. Not sure of your set up, but could be various issues, one being the wrong fuse in the fuse box, or could be something bigger.. Im no expert, but to answer your question, yes one can damage an amp this way.

Kind Regards,
John
 
Do they dim and stay down or just lower for a second when it comes on?

I currently have a lot of stuff hooked up to mine - a Pioneer SX-1250 and a 400 wpc QSC pro audio amp. It's all on a power management unit with delayed start relays but the lights in the living room dim for a second while all that charges up. :D
 
You've got issues.

Might be time to consider adding a dedicated circuit for just the stereo. That's also a good way to isolate noise from all the other stuff running in the house. I did that here years ago.

Also be interesting to find out what you're running for service amps in the house. Most new construction is at least 200 amps, but I know my 80 year old converted cottage had the original 60 amp service from back in the day. That just wasn't gonna cut it in this day and age.

Nice,

My parents hose was built in 1886, and I remember when they purchased it in the early 90's, one of the upstairs bedrooms would constantly trip the breaker. Turned out someone had a penny in the fuse box, with the wrong fuse. You never know with older houses.

Kind Regards,
John
 
It might not be a big deal but if you are overly concerned, just make sure the amp is properly fused. Some of my equipment makes my lights dim for a nano second but that's because I use big tube amps. None of my solid state stuff makes the lights dim........except when cranking it to eyeball rattling levels. :biggrin:

Now if your unit had a power transformer that was stressed and had a possible winding short, this would cause said symptoms. Also bad electrolytics in the power supply would also cause this as it would be loading down the circuit and possibly drawing too much current. The amps fuse would or should blow but I have also had this experience with an amp I had years ago.
 
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If a 70 watt amp dimmed my lights, I would call an electrician. It shouldn't pull more than 3 amps at turn on, indicating a bad connection that could can cause problems down the road. Plug in a hair dryer, on high, with the amp runing and measure the AC voltage at the plug. Low voltage would tell you that something is cooking somewhere.
 
All that you are seeing is the temporary dim caused by the charging of the filter caps of the amp. If there was a real problem, the breaker would trip. Don't panic over this.
 
My house is new construction (8 years), I have a basic Monster power strip/ surge protector between the wall and the amp/ preamp/ turntable (that is all that is on the strip). My house is pretty well protected. We have a whole house surge proctor and this "APC PowerShield" thing that I don't really understand. I am pretty okay with home electrical (I've wired plugs/ switches/ dimmers, replaced blown fuses) so the comment about it being odd doubly concerned me. Audio electronic -- while I love the end product -- is really a mystery to me.

The amp seems to be fused with four running parallel to each other, but none of those have tripped. I do not know if there is a security safety mode on this particular amplifier because 1) I have not seen it 2) there is limited information on it. One tech has been through it within the last 4 years, but I have no training and tend to steer clear of guess and test.

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.

I have a fair bit of use on this amp, but the recent comment has me mainly concerned about my speakers. They are not over the top, but I would prefer not to damage them for no reason.
 
Dear King Bubba,
You do not know what you are talking about. A bad connection may not kick the breaker, it will generate enough heat to start a fire without any other indication. I do not know where this house is, I assume it is copper wire if it is that new. A voltage drop under load will show that there is a problem. All the protection devices on the end of the line will not help you. I am not saying that your 70 watt amp is the problem, unless the noise you hear at the amp is Snap Crackle Pop, when first turned on!!!! I am not trying to alarm anyone.
 
The O.P just has an oversized DBT :D

No, seriously, are you sure you don't have the light circuit wired in series with that power socket ?
Don't laugh, I have seen this happen.
All the responses above are very valid indeed and I would have it investigated thoroughly to ensure, Firstly, the safety of you and your family and secondly, the safety of your prized possessions.
Let us know how you go friend.
 
Which brings to mind another potential bugaboo if you're interested in losing sleep ... <G>

When's the last time yall "exercised" your breakers? Not uncommon for those to go years without tripping, which may sound like a good thing, but chances are decent they won't trip when needed due to oxidation and such. Most of my house is still the old glass fuses, but those breakers I do have get manually tripped a couple times a year. Any GFCI sockets get tested at the same time.

PS ... while the OP is peeking around looking for problems, might be a good idea to start with the wall socket the stereo is plugged into. Those stab connections are easy to slap together, but the next best thing to useless when it comes to power transfer under load. If you've got those, hopefully they left you enough extra wire to strip and use the screw terminals instead. That can work wonders.

And ya, invest in a cheap socket tester ... just plug it in, and read the lights ...

outlet_tester.jpg
 
If it's just a very brief dimming (like a fast flicker), that's perfectly normal and people who tell you otherwise are talking rubbish.

Certain transformers in even low powered amplifiers along with their secondary filter caps can momentarily pull massive currents, enough to dip your house voltage. Conventional lights are particularly sensitive as their light output is very dependent on the voltage- a very small dip can produce a significant and visible change in luminous efficacy.

If the dimming is permanent when the amp is on, you have a problem, as it would only be pulling 1-2 A max on a continuous basis.

That said, my line is currently at 245V and a 2200 Watt kettle plugged into the same GPO will pull the point down to 235V while it is on. My electric oven and hotplates turned on (on a different circuit and purely resistive in load nature) will pull down the entire house's line voltage to 234V. That is purely a function of voltage drop at those currents, over just 30-40ft of copper and the pole to house cable.
 
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And ya, invest in a cheap socket tester ... just plug it in, and read the lights ...
outlet_tester.jpg

Hey, I have one of those. It came in super handy to check the outlet wiring in my house as I've been prepping to unplug and go full solar.

I found 2 outlets that had hot and neutral reversed. Don't know if that would really cause issues with the inverter, but I fixed them just to be on the safe side.

As for this problem, check to see what other items are running on this same circuit. It could be that your amp, in conjunction with maybe a water heater, refrigerator, AC/Heat, or something along those lines is drawing close to the max amps that circuit is rated for.

A dedicated circuit for your stereo, as mentioned earlier, would be an effective solution. Get a trusted electrician involved.
 
Thank you. I will continue to do some work around the house. I will put the security of my family way out front of the two channel system.

The amp is hand built bit, but it was built by the folks at the old B&K Components LTD group -- that gave me some confidence. Musical Concepts/ Musical Design is the only shop with any knowledge that assures its existence. They had their hands on one, but he was not able to give me any hard info on my unit. Luminance Audio was also interested, but they were also not able to nail anything down.
I do not have the email address for some of the core folks that overlap the two companies.

The amp sounds very good to my ears. It replaced an amplifier that had dropped a channel, the price was good, and the faceplate matches well with the rest of my parts. I didn't think too much past that when I bought it.
 
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So, do the lights stay dim or is it momentary when the amp is powered up? The latter is normal, but is they stay dim Freddymac2 is right; you may have a bad connection which would be a fire hazard.
 
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 new one probably has much larger filter caps in the power supply that take more juice to charge up initially. Wattage of an amp doesn't necessarily translate to capacitance.
 
If a 70 watt amp dimmed my lights, I would call an electrician. It shouldn't pull more than 3 amps at turn on, indicating a bad connection that could can cause problems down the road. Plug in a hair dryer, on high, with the amp runing and measure the AC voltage at the plug. Low voltage would tell you that something is cooking somewhere.

I have a 100wpc amp that I have measured to pull over 100A peak current for about 1 cycle or so during power up due to 130,000uf of capacitance to charge up.

It makes the lights dim for a split second on power up. It causes zero problems for normal operation.
 
The amp in question doesn't have 130,000uf of capacitance, I would still load the circuit and read steady state voltage, whoare you?
 
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