[eyeteeth]

Not refering to people in lightening strike prone areas but to users like myself in large metropolitan areas and I'm in a 30 story building. Sure the AC may be dirty, but is it dangerous for my components?
Is the fear of power surges realistic or just part of the sales gimmick to sell protection devices?
The "can you afford to take chances" line keeps occuring to me.

So what's the deal with the fuse in the back of my amp?
Is that not designed to protect it?

Thanks intrepid seekers of the truth

 

[rickcr42]

Quote:

Not refering to people in lightening strike prone areas but to users like myself in large metropolitan areas and I'm in a 30 story building. Sure the AC may be dirty, but is it dangerous for my components?

Dangerous or at least can be.Any high current device when it switches on has the potential to throw a big time surge or spike on the line-even a lowly refridgerator can do this as can an air conditioner or washer/dryer.

Not saying it happens all the time to everybody but why chance it ?
If you do not have a dedicated clean line,a home run right to the breaker box then it is only smart to cover yourself.

I know a lot of people that never have had a fire but they still carry fire insurance just in case

 

[sluggo]

Quote:

Originally Posted by eyeteeth So what's the deal with the fuse in the back of my amp? Is that not designed to protect it?

Sort of, but not really. The fuse is really there to protect the rest of the world from your amp. If something breaks on the inside of your amp such that "a lot" of current is allowed to pass through it on it's way to ground, then your amp may turn into a hot thing and start a fire. In oder to get UL certification you have to have a current interrupting device (fuse, PTC, breaker, etc) in-line. It's also just good engineering practice.

The fuse blows not to protect your amp (it's already broken), but to isolate the amp.

As far as surges go ... mmmm ... I'm not a big believer in the surge protectors. Cycling refrigerators, waching machines, etc will cause surges and sags, but these are in the +/- 30V range. Protectors will do nothing for that, and nothing for the random 100-200 volt transients. Yes, they're nice for lightning hits, but if there's lighting in the area you should prolly unplug anything you really care about.

 

[ServinginEcuador]

eyeteeth,

Noise is going to be the biggest problem for you. Living in a large, populated building like that will dirty up the AC lines pretty badly. Whether you have spikes or surges large enough to kill a piece of gear is hard to say.

A few questions:
1. Have you ever had something electronic suddenly die on you?
2. Has anyone in your building had anything die suddenly on them?
3. Do you have a superintendent or someone else who takes care of the building who you could talk to about electrical issues like this?
4. How much is the gear you're trying to protect worth vs. the cost of a decent surge protector? IOW, is it worth it to spend the amount of money it takes to properly protect your gear with something other than a cheapo MOV?

Just some questions to think about, you don't need to post your answers here, they're just food for thought.

 

[Wodgy]

Kelly (one of the earlier Head-Fiers) lost a couple pieces of fairly expensive gear to power surges. I've never lost anything through a power line surge, but I have had a modem wrecked by a power surge on the phone line.

 

[rickcr42]

you may finfd this interesting-

http://www.rocketroberts.com/techart/power.htm

Just something at hand,i can provide far more detailed info if needed.


It is my belief the power supply of an audio device is as if not more important as the actual audio delivery circuit.

99% of audio devices are amplifiers of one type or another : low level,line level,headphone level,speaker level.
and these amplifiers do what ? Convert the power line voltage into an audio voltage !
Yeah,a bit more detailed than that but the essence is just that.
Think of a single transistor amplifier and it will have an input,a power inut and an output and that is it !
Your basic "single ended amplifier".So for it not to be sensitive to any fluctuations or surges would be the surprise.

Tube gear can take a hell of a beating due to the voltages involved and construction methods of the tube itself.They don't take a "physical" beating so well but electrical beatings they shake off like a red headed stepchild who gets one daily

Transistor gear can take the physical beating but not the electrical and is actually TOO sensitive to static,surges,over voltages,etc.
One nice inductive zap down the line from a washer motor and it CAN be "see you later dude.I'm otta here" !

For this reason you will find all manner of input and power supply protection devices (diodes mostly) meant to keep that delicate sucker protected.
With tube gear you will find NO protection at all for the circuit itself.All those slow turn on devices are for saving your speakers/headphones from thumps and spikes and not the device.That should tell you all you need to know about tough. Yeah,there are some circuits meant to stress the tube less but that is for tube life not immediate tube failure.

BTW-digital and video gear is even more sensitive due to the high frequencies of the signal which will pick up on problems your other gear will not even notice.Same with computers'

Quote:

A few questions: 1. Have you ever had something electronic suddenly die on you? 2. Has anyone in your building had anything die suddenly on them? 3. Do you have a superintendent or someone else who takes care of the building who you could talk to about electrical issues like this? 4. How much is the gear you're trying to protect worth vs. the cost of a decent surge protector? IOW, is it worth it to spend the amount of money it takes to properly protect your gear with something other than a cheapo MOV?

1-Yes.Why ? Who knows.And THAT is the problem ! No one knows why something that was previously operational suddenly quit unless you open it up and attempt to track down where the problem is and then you still can only guess at the actual cause.

2-have never lived in a "building" if by that you mean apartments so i can not answer that but i being who i am get questions all the time like "jeez Rick.My VCR worked fine then it just quit for no reason.What do you think happened ?",
to which I usually respond "Sabotage man ! Someone must really hate your guts ! Electronic equipment should last forever and only craps out if someone messes with it or the warranty runs out.Then it just self destructs so you have to buy a new one"

3-are you serious man ? Have you ever actuallyTALKED to one of these "supers" ?
The fact that the building does not burn down or blow up is pure dumb luck with some of these knucklheads doing the work.Having "skills" is not part of the job description and if you think my answer above ridiculous ask one of them a technical question.

4-any reasonable quality protection system has a money figure attached that the company will pay out to replace your gear if the surge protect fails to do its job.
Even a $200 system if that is all you can afford is not easily replaced if it gets taken out by the neighbors washer.

Quote:

Just some questions to think about, you don't need to post your answers here, they're just food for thought.

Munch away man.the "buffet' is open

Quote:

Sort of, but not really. The fuse is really there to protect the rest of the world from your amp. If something breaks on the inside of your amp such that "a lot" of current is allowed to pass through it on it's way to ground, then your amp may turn into a hot thing and start a fire. In oder to get UL certification you have to have a current interrupting device (fuse, PTC, breaker, etc) in-line. It's also just good engineering practice.

wrong answer.A fuse is a safety valve meant to protect the equipment.Current can not pass back to the line through a broken amp but without a fuse your amp will continue to draw current in some cases when a single part goes bad (from a surge ?) which will then damge more parts drawing more power and on and on until total destruction or a fire breaks out.
Think of a car stereo.When i was young we were alsways jury rigging our gear,not paying attention to any proper methods as long as we got sound !
I was with my cousing in his Challenger and he had just "jury rigged" his cassette deck and had it wired up but just sitting on the hunp where the shifter is .He went around a corner and something must have made contact with a car ground because the fuse popped.
Well this knucklhead wrapped foil around the fuse and popped it back in.No WAY was he doing without his 'Tunes' !

And down the road we went.........until the smoking started and the amp caught on fire !
If that baby was properly mounted behind the dash he would have lost his car before we could have removed it.No we did not have a fire extinguisher either.How many 16 year olds do ?
We ripped that b*tch out and tossed it out the car window then had a good chuckle about it.
Later when we were hammered we told everyone our "fire story" to everyones delight

Everything you survive without major damge or serious injury,especailly the dump crap, is funny.

But the car battery suffered no damage.Just the deck and the carpet where it got scorched.
The house itself is the same and has ITS OWN protection devices.Earth ground and Breakers.

The U.L. analogy is also meaningless.You can add all the breakers,fuses,gadgets you want and still not get certified.Way more to it than that.

Quote:

The fuse blows not to protect your amp (it's already broken), but to isolate the amp.

already addressed as wrong.

Quote:

As far as surges go ... mmmm ... I'm not a big believer in the surge protectors. Cycling refrigerators, waching machines, etc will cause surges and sags, but these are in the +/- 30V range. Protectors will do nothing for that, and nothing for the random 100-200 volt transients. Yes, they're nice for lightning hits, but if there's lighting in the area you should prolly unplug anything you really care about.

Don't know who is feeding you this stuff but also not close to the truth.A surge is not some small blip but a major ramping up of the voltage from a known steady state value .
This "spike" or "surge" can be a thousand volts or better !
And because the duration is very short the fusie can not catch it.If fuses reacted rapidly you would be replacing them all day long.Even "fast blow" means slow when talking about a fuse.

Just like with an audio amp rated to deliver 25 watts RMS that can deliver far more peak power for music your power line can and does do the same.But in this case it is not a help but harmful.

you folks really need to do some research.Not the easy stuff,the manufacturer ad copy but the REAL crap from an electrical site (not electronic but electrical).These are well known issues in the trade and steps are taken in new homes to prevent these occurances,the simplest of which is the "home run".
A dedicated clean line all the way back to the breaker panel for the main computer and for the main audio system.

no one ever heard of lost data from power line surges ?
Fax failures ?
Modem disconnects ? (in the pre high speed days

)

so munch away on my serving of "food for thought"

 

[eyeteeth]

Quote:

Originally Posted by rickcr42 so munch away on my serving of "food for thought"

OK, I'm full. I couldn't eat another bite!

Yeah all seem to be in agreement at least for insurance/why take a chance reasons.
My integrated amp goes for $4,200 and that would break my heart (& wallet) were it to start smoking.

Thanks guys.

 

[sluggo]

Quite a lot to chew on here.

Quote:

Current can not pass back to the line through a broken amp

It most certainly can. The primary side of your transformer shorts out. Is the amp broken? Yes. Is it still pulling current? Yes. Do you have a potential fire hazard? Yes.

Quote:

but without a fuse your amp will continue to draw current in some cases when a single part goes bad (from a surge ?) which will then damge more parts drawing more power and on and on until total destruction or a fire breaks out.

Are you trying to make my point for me or did you change your mind in mid-sentence?

Quote:

But the car battery suffered no damage.Just the deck and the carpet where it got scorched.

Extending the analogy to the home, the generating station will suffer no damage if your amp's power supply shorts out, but your house may burn down.

Quote:

The house itself is the same and has ITS OWN protection devices.Earth ground and Breakers.

And how much heat do you suppose you can safely dissipate in a 100VA power supply core? I'll tell you - it's a lot less than the 2500 Watts the wall will provide on an untripped 20A circuit.

Quote:

The U.L. analogy is also meaningless.You can add all the breakers,fuses,gadgets you want and still not get certified.Way more to it than that.

Did I say that was all there was to agency certification?

Quote:

Don't know who is feeding you this stuff but also not close to the truth.A surge is not some small blip but a major ramping up of the voltage from a known steady state value .

I was fed most of this stuff by my employer and the reps I worked with from UL and VDE. And the definitions we used for "spike" and "surge" varied based on the equipment and the application. In general, though, a spike lasts less than one AC waveform and a surge last longer than one AC waveform. And yes, a surge can be a small blip, as little as 20% over nominal.

Quote:

This "spike" or "surge" can be a thousand volts or better !

Residential electrical distribution voltage is 10kv. If you get a 1000V surge at your home then you've got 100kv on the distibution circuit, and the utility has far better protection devices than you can buy to prevent this from happening. High voltage spikes from large appliances can occur on the local loop, though, and that's one of the reasons why houses are wired with the major appliances (dishwasher, laundry, etc) on dedicated circuits.

Very fast, high voltage transients (from yours or your neighbor's skilsaw, hairdryer, etc) occur all the time, but no standard surge suppressor will eliminate them.

Anyway, my point was that the fuse is there not to protect the amp (as I said, if the fuse blows it means the amp is already broken), but to prevent fires. MIGHT the blowing of the fuse prevent FURTHER damage to the amp? Maybe, probably, who knows? If you want to protect and amp from itself, you don't just slap and AC fuse on - you fuse the AC, the bridge, both rails, and the load(s).

 

[jpr703]

I've lost two hard drives due to two seperate ligtning strikes very close to my house. My computer has always been on a UPS and there was no other damage to it or any other electronics in the house (protected or unprotected).

I'm not sure exactly why this happened unless the surge came in through the cable modem (although there was no damage to the TVs), or if it was just the airborne electromagnetic field that the ligtning strikes produced.

I tend to think that it's the latter and I'm starting to question the value of suge-surpressing devices myself.

I read in another thread on a different board some time ago that uninterruptable power supplies weren't good for audio equipment because the power that they put out is often released a stepped sine wave that can introduce more distortion into your system than a little bit of "dirt" in the AC. I'm not 100% sure if that's true or not, but it seems to makes sense.

 

[sluggo]

Quote:

Originally Posted by jpr703 I've lost two hard drives due to two seperate ligtning strikes very close to my house. My computer has always been on a UPS and there was no other damage to it or any other electronics in the house (protected or unprotected).

Sorry about your drives. I guess I'd agree with your theory about the field induced by the strike - the read preamps on a modern disc drive are working with microvolt levels, and I could see how they could be damaged by the sort of voltage generated by the field.

 

[Edwood]

I've lost a modem due to surges in a storm.

Also, a PSU blew up on me after a storm.
After losing a computer that was on a cheap surge strip, I use series mode surge suppressors on all my "mission critical" equipment now.

When living in apartments, lights dim and flicker whenever anyone uses a microwave oven, printer, vacuum cleaner, etc. Definitely affects sound quality.

Now I live in a condo with my own breaker box. I've given a dedicated line to my audio equipment, and my computers are on another. But still, there are alot of brownouts. Particularly in the middle of the night when it gets windy.

-Ed

 

[rickcr42]

Quote:

It most certainly can. The primary side of your transformer shorts out. Is the amp broken? Yes. Is it still pulling current? Yes. Do you have a potential fire hazard? Yes.

wrong !

Once electrical equipment shorts out it begins to draw current at an exponentail rate of increase that due to the time constant and current change involved will trip any breakers or fuses cutting off ALL further electrical draw from the grid.No juice into the device period.
This is precisely what protects from fire hazard and is part of building code.Unlimited current draw allowance in general is looking for trouble and would cause intenal house wiring to overheat until the dielectric broke down causing the wires insultaion to burn and cause an "in wall' fire.That is why you have these various "bottlenecks" at certain juntions of the AC grid.
the lowly fuse is solely to protect the equiment itself from drawing too much current which is FAR below that allowed by the line itself and can even be in the % of amps rather than amps or tens of amps.
Do the reading.Check out the EC (electrical contractor) sites (ECM Magazine in particular is good)

I could take the rest of your points one by one and slam them but instead suggest the above reading/research because someone is giving not just bad but dangerously bad information and if it were not AC i would let it go but to leave misinforamation as gospel I can not.
I have personally rough wired from blueprints entire homes and I know wiring and code and the reason behind each.On the flipside I have been also done the "past the fuse" internal electronics side of things and since i have shorted out and blown up more than the average human I know how these things work and what happens AFTER the short circuit situation..

not theory but "been there and done that" on both sides of the "fuse"

 

[sluggo]

Quote:

Originally Posted by rickcr42 wrong !

Again, you seem to be making my case for me. You point out that unlimited current draw is "looking for trouble" in response to my statement that fuses are there to prevent fires. You then claim that the fuse is there to prevent excessive current on a circuit with an untripped breaker, and you use this argument to refute my claim that the fuse is there to prevent excessive current on a circuit with an untripped breaker.

The dI/dt of a shorted transformer in a 25 Watt receiver is far less than the the turn-on surge of an electric heater or a large motor circuit. Besides, many breakers are simple level-triggered devices, so whatever you're trying to say with "exponentail rate of increase" and "time constant" doesn't apply.

That shorted transformer will not trip a 20A breaker, and it will overheat and could lead to a fire. Do you really think that UL gives a hoot what happens to the rest of your product after a single fault condition arises? No, they do not. But they still demand that you use a fuse, regardless of whether you connect the product to a test circuit with fast breakers or you hardwire it to Hoover Dam. So why are they so adamant about it? Because it prevents fires, which is the business that UL is in.

Do the reading? While you were pulling wire through houses and blowing stuff up, I was designing three-phase power systems for mainframe computers, from the power cord to the +5 rail, and blowing up a fair number of things as well. As far as "the other side of the fuse" goes, I also wrote the power section of the site prep manuals for these machines, so feel free go through my points one by one and slam anything I have to say - it won't be the first time I've been edited.

And where am I giving out "dangerously bad information"? Am I telling people to replace their fuses with wire? Am I saying you should remove your breakers and hardwire your house? What is your point here?