Using a regular power adaptor versus a switching power adaptor?

[baker]

Hello everyone.

I have a Phillips ipod dock that uses an 18 volt 1.6amp DC switching power adaptor and I was wondering whether anyone here would know if I would be able to use a normal power adaptor that is 18 volts 3.5 amps DC but it isn't a switching version though. Will there be any harm in using a power adaptor that is not switching for my ipod dock?

Thanks

 

[sahib]

As long as the normal (linear) one is regulated just use it.

 

[baker]

Thanks sahib.

I manage to find an adaptor that is 1.5amps switching but not 1.6 amps. Would the 0.1amp difference make an impact or damage the ipod dock?

 

[Andy Peters]

Thanks sahib.

I manage to find an adaptor that is 1.5amps switching but not 1.6 amps. Would the 0.1amp difference make an impact or damage the ipod dock?

It won't damage the dock, but if the product indeed needs 1.6 A to work (which is doubtful), it might be starved for current.

-a

 

[baker]

Thanks Andy

When something is starved for current, what can happen?

On a similar note, I was told that my stereo power supply blew up and melted because of a hair dryer that was plugged in on the same line and that it drained the house power and made the stereo run under powered.

What do I need to get to protect my stereo from such occurrence? Will a hardware store surge protector work or do I need something specific? I need something simple and affordable that would prevent my equipment from blowing up or melting due to underpower.

Thank you

Thanks sahib.

I manage to find an adaptor that is 1.5amps switching but not 1.6 amps. Would the 0.1amp difference make an impact or damage the ipod dock?

It won't damage the dock, but if the product indeed needs 1.6 A to work (which is doubtful), it might be starved for current.

-a

 

[Andy Peters]

Thanks Andy

When something is starved for current, what can happen?

The power supply drops out of regulation. It can oscillate and do all sorts of weird stuff.

On a similar note, I was told that my stereo power supply blew up and melted because of a hair dryer that was plugged in on the same line and that it drained the house power and made the stereo run under powered.

Told that by whom? That's rather unlikely. If the load presented by the stereo and the hair dryer and whatever else are too high for the circuit, the breaker trips.

Now it's possible you had a low-line voltage condition, which is your utility's fault, and a low line means the transformer could overheat. But most power supplies are designed to accommodate some reasonable low-line conditions, and worst case the regulators would drop out of regulation and stop working.

Perhaps there was something wrong with your house's mains wiring.

What do I need to get to protect my stereo from such occurrence? Will a hardware store surge protector work or do I need something specific? I need something simple and affordable that would prevent my equipment from blowing up or melting due to under power.

Surges are by definition an over-voltage condition, not a low-voltage condition, so a surge protector won't help. An on-line UPS, which always runs off of its battery, is probably the only way to ensure that your equipment gets a steady mains voltage but it's also the most expensive, especially if it has a true sine-wave output.

I'd check the mains wiring. If it's low or high, call the utility, they want to know, and they will fix it.

I don't have any surge protector or such on any of my stereo stuff.

-a

 

[baker]

Andy,

The breaker did trip.

There was a loud pop that I heard near one of the stereo and only one was playing and the other on standby and then smoke started coming out of the stereo that was on standby. The one that was playing, well it smelt funny and liquid was pouring out of it. Not sure what that liquid was but it smelt toxic.

When you say "worst case the regulators would drop out of regulation and stop working."
Do you mean the stereo will stop working because it is broken or will the stereo temporarily stop working and come back working again once the low line is normal again?

The house main wiring works OK and it was checked recently to be OK and if that extra load of the hairdryer or I think it was a hair straightener wasn't connected, that line in question runs OK. I checked the voltage at the power outlet and its 235 volts.

 

[Andy Peters]

Andy,

The breaker did trip.

There was a loud pop that I heard near one of the stereo and only one was playing and the other on standby and then smoke started coming out of the stereo that was on standby. The one that was playing, well it smelt funny and liquid was pouring out of it. Not sure what that liquid was but it smelt toxic.

It's likely that the stereo's power supply had an issue, and its last will and testament was to develop a short which melted it down and finally tripped the breaker.

When you say "worst case the regulators would drop out of regulation and stop working."
Do you mean the stereo will stop working because it is broken or will the stereo temporarily stop working and come back working again once the low line is normal again?

The latter.

The house main wiring works OK and it was checked recently to be OK and if that extra load of the hairdryer or I think it was a hair straightener wasn't connected, that line in question runs OK. I checked the voltage at the power outlet and its 235 volts.

I don't know where you live, but here in the colonies mains service is 120 V except for things like clothes dryers and stoves which are 240 V. If I measured 235 V at an outlet, I'd get it fixed immediately.

-a

 

[PRR]

In the US, I plugged a power amp into a "117V" outlet. It sounded unusually good. About 10 minutes later "BOOM! and a mini mushroom cloud of smoke. Main power cap burst.

Meanwhile in an adjacent office the coffee maker wouldn't get hot.

> here in the colonies mains service is 120 V except for things like clothes dryers and stoves which are 240 V.

Right; and there are two 120v buses which are actually a 240V center-tapped supply.

What happened to me was the building center-tap had a bad connection. In effect my 60W amplifier and the 600W coffee-maker were in series across 240V. The amp is a higher impedance (lower power at rated voltage) so by series-Ohms laws it took more voltage. Possibly over 200V (in a 120V-rated amp). There's a lot of safety-factor in an old Yamaha, but not _that_ much. Boom indeed.

In 230V lands you "usually" don't use a split-phase center-tapped supply in the house. There's a center-tap (on a 3-phase Y) out in the street, where it is usually much better maintained and not as subject to single loads.

 

[JohnRoberts]

In the US, I plugged a power amp into a "117V" outlet. It sounded unusually good. About 10 minutes later "BOOM! and a mini mushroom cloud of smoke. Main power cap burst.

Meanwhile in an adjacent office the coffee maker wouldn't get hot.

> here in the colonies mains service is 120 V except for things like clothes dryers and stoves which are 240 V.

Right; and there are two 120v buses which are actually a 240V center-tapped supply.

What happened to me was the building center-tap had a bad connection. In effect my 60W amplifier and the 600W coffee-maker were in series across 240V. The amp is a higher impedance (lower power at rated voltage) so by series-Ohms laws it took more voltage. Possibly over 200V (in a 120V-rated amp). There's a lot of safety-factor in an old Yamaha, but not _that_ much. Boom indeed.

In 230V lands you "usually" don't use a split-phase center-tapped supply in the house. There's a center-tap (on a 3-phase Y) out in the street, where it is usually much better maintained and not as subject to single loads.

When I had my high mains voltage event, I went out to my fuse panel and measured 270V+ across the two 120V legs to confirm that I really did have high voltage coming from the drop and not just an open center tap, before calling the utility to complain.

That open CT should be rare, but worth verifying.

JR