Please help me stop breaking my nice things

[Imp]

xpost audio repair

tldr: Multiple receivers have been fritzing but only while plugged into one outlet. Brought one home from the store that worked great there and it blew a fuse as soon as I pushed the volume above 1/4. Outlet w/ cheap surge protector is powering turntable, receiver, and has unpowered projector plugged in. How do I stop this from happening and have I fried things already?


I had a Pioneer 737 that started to make clicking sounds when the volume turned up while powered by one outlet. I then moved the whole system around and ran it through another outlet. Plugged into that outlet via shitty surge protector was an Acer projector (powered off), a Bang and Olufson vintage turntable, and the receiver. The Pioneer, upon powering up, can provide audible sound when volume is low but when turned up just clicks. Also, something is lighting up/sparking. I did check this receiver at another outlet and the problems persisted.


After that I test out two Craigslist Marantzs. Both distorted at medium volumes and one has a blinking light that flasheserratically at high volumes visible thropugh the grate. I think the problem is bad craigslist vendors. Finally, I go to a real shop and pick up a Harman Kardon 430 Twin Powered. Take it home last night, hook it up to my turntable and speakers and turn up the volume a little bit and the whole thing powers down. I check the back and you can see that the removable fuse back there is blown.


I know that I won't be using that outlet any more, but beyond that I don't really understand the problem and I'm afraid I'm hurting nice gear and wasting lots of money. My building is almost 100 years old so there's maybe some weird wiring. Is there anything I should be careful of when I switch out the fuse for the HK and plug it into another outlet? Can someone with a functional understanding of electricity clarify what has been happening with this outlet? Please note that none of the receivers have been able to get very loud at all since being plugged into the bad outlet; I'm not just blasting them.


If it matters, right now the system is hooked up to two shallow but tall bookshelf speakers with no brand that I assume are custom and I picked up used. I also am running one of them with shorter pieces of speaker wire that I twisted the ends together to cover a longer distance. The speakers worked fine with the Pioneer when everything was plugged into the other outlet.

 

[woofmytweets]

i'd buy a UPS which will monitor the outlet voltage and protect your devices whether you have too much voltage or not enough.

also, it could be the speakers, if they're really low impedance, that could be cooking your amps too...measure them with an ohm-meter and post results.

and be SURE your piece-meal speaker wires are not shorting.

i'd actually be surprised if it was the outlet, and not one of the other 2 things.

 

[moewillis]

welcome to the world of vintage gear.

i kinda doubt the outlet is the problem. take a meter and test the voltage on the outlet

 

[willyrover]

Have devices worked fine in this outlet in the past? Have you measured voltage at the outlet?

Could it be an old 220 volt "air conditioner" outlet with the wrong receptacle wired in?




Power supplies in many newer devices will work on multiple voltages. They just need an IEC cord that will fit the outlet. For example my Panasonic LCD TV and Epson LCD projector both have automatic worldwide voltage. They will be perfectly happy with 100-240 volts.

If it is a 220/240 volt outlet, that "could" explain why some devices are working fine and others are not.

 

[ggregg]

Check the speaks and wiring.

 

[whoaru99]

For starters I'd check the voltage. If the place has 120/240 split phase power then a bad neutral connection can allow the two legs to become significantly imbalanced in voltage.

Do you notice any other oddities with the power in general?

 

[nj pheonix]

I agree it sounds like a power or speaker issue. Even if outlet worked fine in the past. Doesn't mean something didn't come loose.
Test with voltmeter ( something that shows actual value. ( I'd start there).

 

[musichal]

Sounds about par for the course for some vintage gear, to me. Check condition more thoroughly before handing over your dough. Subscribe and gain access to Barter Town - a better class of sellers than CL, overall.

 

[Dr Tinear]

welcome to the world of vintage gear.

i kinda doubt the outlet is the problem. take a meter and test the voltage on the outlet

It's possible, though not terribly likely, that the outlet is delivering an AC voltage that's less than 240 VAC, but greater than 120 and high enough to damage audio gear. Electric power in the U.S. is typically 120/240 VAC single phase 60 Hz. The wiring from the pole pig (transformer) to the house consists of two wires, Line 1 and Line 2, with 240 VAC across them. The center tap of the pole pig's secondary winding goes to earth ground. The service panel brings in Line 1, Line 2, and earth ground. The Neutral (white) wire, which gives you 120 VAC relative to either of the Line wires, connects to earth ground inside the service panel. Circuit breakers for 120 VAC branch circuits connect to one of the Line wires. The wiring run on the load side of the breaker consists of a black wire that carries the breaker output (Line 1 or Line 2, fused); a white Neutral wire that connects to an earth ground bus in the service panel; and an earth ground wire, usually uninsulated.

Now ... if the connection from the pole pig's center tap to ground breaks, the voltages from Line 1 to ground and Line 2 to ground could be quite different from each other and quite different from the expected 120 VAC. Same thing happens if the service panel connection to earth ground goes open. An AC voltmeter check at multiple outlets on several different breakers should reveal this problem. Some of the line-to-neutral voltages will be less than 120 and some will be greater.

 

[moewillis]

It's possible, though not terribly likely, that the outlet is delivering an AC voltage that's less than 240 VAC, but greater than 120 and high enough to damage audio gear. Electric power in the U.S. is typically 120/240 VAC single phase 60 Hz. The wiring from the pole pig (transformer) to the house consists of two wires, Line 1 and Line 2, with 240 VAC across them. The center tap of the pole pig's secondary winding goes to earth ground. The service panel brings in Line 1, Line 2, and earth ground. The Neutral (white) wire, which gives you 120 VAC relative to either of the Line wires, connects to earth ground inside the service panel. Circuit breakers for 120 VAC branch circuits connect to one of the Line wires. The wiring run on the load side of the breaker consists of a black wire that carries the breaker output (Line 1 or Line 2, fused); a white Neutral wire that connects to an earth ground bus in the service panel; and an earth ground wire, usually uninsulated.

Now ... if the connection from the pole pig's center tap to ground breaks, the voltages from Line 1 to ground and Line 2 to ground could be quite different from each other and quite different from the expected 120 VAC. Same thing happens if the service panel connection to earth ground goes open. An AC voltmeter check at multiple outlets on several different breakers should reveal this problem. Some of the line-to-neutral voltages will be less than 120 and some will be greater.

That's all fine and well but he is talking about 1 outlet. Way Over the top there. I see you flexing your intellectual muscles though . My comment was suggesting that he may be finding out what it's like to own a lot of vintage gear and it has nothing to do with the outlet. Plus I would imagine he would see it elsewhere.

Check it with a meter. If you don't have a meter plug a lamp in it and leave it on. Observe if anything odd happens. Simple

 

[Dr Tinear]

That's all fine and well but he is talking about 1 outlet. Way Over the top there. I see you flexing your intellectual muscles though . My comment was suggesting that he may be finding out what it's like to own a lot of vintage gear and it has nothing to do with the outlet. Plus I would imagine he would see it elsewhere.

Check it with a meter. If you don't have a meter plug a lamp in it and leave it on. Observe if anything odd happens. Simple

If the OP has a bad neutral, it's only a matter of time before other electronic devices or appliances start failing mysteriously. Diagnosing this problem can be tough. That's why I went into considerable detail in my post.

 

[moewillis]

If the OP has a bad neutral, it's only a matter of time before other electronic devices or appliances start failing mysteriously. Diagnosing this problem can be tough. That's why I went into considerable detail in my post.

Again he is commenting about 1 outlet. One in which a power strip is plugged in and other items are plugged into it. (Unless I misunderstood something).

The issues described sound like common problems from vintage gear not power problems.

He's got 1 outlet he's plugging tired old worn out gear into... That's my bet anyway

 

[nj pheonix]

While I don't dispute Dr Tinnears story. I still think OP ought to test the outlet with a halfway decent voltmeter.
It's certainly a reasonable theory and possibly right ( though the fact that as I understand it, nothing else in the house has an issue seems to make it less likely.
Oh, BTW I am an electrician and haven't played one on TV. My point is let's start with what we know for sure, before we go hunting for the reason.
Also open neutrals can happen in local branch circuits fed with 3 wires so it could not be at the pole or the service. Why don't you see what you have first before going hunting.

 

[Freddymac2]

For all of those that feel this kind of failure of vintage gear is to be expected, I disagree. Not that it is perfect, and without problems, or needed repairs, for sure. My whole system is vintage, and if I couldn't buy old quality used stuff, my system would not sound as good as it does. Audio equipment sonic quality has not improved much in the last thirty years.
The Op will likely find, a bad speaker wire (just replace them) or shorted or low resistance speakers (get a Tek 10709 meter from Walmart for $14 and learn how to use it without burning the house down) or your power outlet, power strip, or house wiring is at fault. (plug a toaster or electric heater into the strip and turn it on and read the voltage at the strip with your new meter.) IF YOU LEAVE THIS PLUGGED IN FOR MORE THAN 2 MINUTES WHEN READING LOW VOLTAGE WHAT EVER CONNECTION THAT IS BAD WILL GET HOT AND SHOW YOU THE WHERE THE PROBLEM IS. IF YOU LEAVE IT ON FOR 10 MINUTES GET A FIRE EXTINGISHER! From what is described by OP, my bet is on speaker, or connection to them. Good Luck!

 

[whoaru99]

I use one of those milkhouse-type heaters for loading household circuits. Some hair dryers pull a fair chunk of current too.

 

[moewillis]

For all of those that feel this kind of failure of vintage gear is to be expected, I disagree. Not that it is perfect, and without problems, or needed repairs, for sure. My whole system is vintage, and if I couldn't buy old quality used stuff, my system would not sound as good as it does. Audio equipment sonic quality has not improved much in the last thirty years.

oh god, not this again

 

[ggregg]

What the hell is wrong with that? Just stating something that works for him. Don't like it, don't read (or quote) it. It just fuels a battle that will never go away.

 

[moewillis]

What the hell is wrong with that? Just stating something that works for him. Don't like it, don't read (or quote) it. It just fuels a battle that will never go away.

nope just waiting for the first person that disagrees with this statement

"Audio equipment sonic quality has not improved much in the last thirty years."

ive seen this go round and round a zillion times. and for the record its comments like that fueling the battle

 

[ggregg]

So you stated a comment certain to create a disagreement, then I respond, and it's my fault. OK it get it......

For the record, many folks state many things that many don't agree with.

 

[moewillis]

So you stated a comment certain to create a disagreement, then I respond, and it's my fault. OK it get it......

very obvious you dont get it. you are being unnecessarily defensive. i never blamed or accused you of anything. reread my post without a bias in your head

and it wasnt me making a comment certain to create a disagreement