240 Volts... ish.

[smash]

So I've recently discovered that my "240 Volts" coming out of my wall socket is actually much higher...

I've borrowed just got a big chunky UPS, that measures input voltage, and over the last hour my AC voltage has
been swinging from 250V to 260V averaging @ 257 V.

I've spoken to energy australia, who is sending over a tech, but basically they said unless the tech sees a spike of
263 Volts, or greater, than the power falls within spec.

I've heard stories about over-voltage cooking gear, we're running a number of Valve Pres, an Amek Console,
a Studer tape machine, and a couple of Mac's with AD/Da Converters - as well as the usual guitar amps and monitors.

The Mac's and Converters are running off a UPS, but that doesn't regulate the volume, and the console and pre's are
running off a power conditioner - that also doesn't convert the voltage.

Can any of the Tech heads here advise whether this is likely to be a problem, in terms of reliablity of any of our gear?

Thanks.

[JulienG]

Ouch. In both my last house and two offices ago the nominal mains was 252Vrms, haven't measured anything since then, although my current house is right under a *MAJOR* feeder line that would be > 110kV and the only issues it gives me is a little hum on my crappy turntable, none of my balenced gear cares.

[wez]

i've been using an online UPS now for the last few years and i have found it to be absolutely essential. it has removed all the rubbish, and of course keeps the voltage stable. totally eliminates those annoying glitches and clicks.

i've got everything running off it other than the amp, when i can i'll upgrade to a bigger one to cover that too.

[Thirteen]

It's pretty ugly, considering that so much gear is actually designed for 220V. I'm surprised so much gear survives our power sometimes, 264V is 10 percent over spec for 240V rated gear, and 20 percent over for 220V rated gear. There must be a reasonable tolerance built in to most gear, but surges are a worry more than spikes.

I don't think that UPS's regulate the line voltage on the output, they just clean it up some. To get a stable regulated 240V output I think you would need a Cleanline or something similar, with a buck-boost transformer to actually step the voltage up and down to keep it in a tight tolerance. Having said that a UPS would probably soak up a lot of spikes and small surges.

[Kurt]

A good quality ups should charge the battery off the incoming voltage and power its output off the battery through an inverter, allowing the steady output of rated voltage no matter how the input fluctuates. Unfortunately I think the "home use" ones (the ones we can actually afford) don't isolate in from out.

I think unless you've paid substantial money for the ups then it probably doesn't help all that much. That said, server grade ones do come up second hand, often needing new batteries, relatively cheaply.

[smash]

It's an MGE Pulsar Evolution 1100

It's a "Line Interactive" UPS,

An online UPS will always independently regulate the output, thus always providing "ideal"power.
An offline UPS will only regulate the power when the UPS is running off batteries, for the rest of the
time you are subject to the vagrancy's of Energy Australia.

A "Line Interactive" os basically an off-line UPS but with an internal set of relays that can regulate voltage without
having to invoke the batteries.

A potential disadvantage of a "Line Inteactive" design is the stress placed on the power supply when the relays kick in.

I've got mine running in Line Interactive mode now, but I've set the trigger voltage really low so that basically the step down
relays (the technical term is a "fader" w00t) are always on.

My input voltage is still reading 255V, but my output voltage has been a pretty steady 220V.

I'm just waiting to hear back from the distributor to see if there is any chance that I'll break anything by doing this.

Would have loved to grab the full on-line model, but just couldn't afford it.

My one retails for $1300, but the distributor had one from a cancelled order, and she's a friend... so I paid $500.
The online model I would have paid roughly $1.8k for.

[Stephen C]

Some well-protected PA amps I have worked on had mains voltage cut-out relays. They must have forgotten setting the threshold from the factory, as when I tested the new amps they were cutting out at 255volts and this was well below the 10% threshold that the amps were designed for. Imagine the amps shutting down at a gig because the mains went up a bit! would be a total disaster!

[rob]

the Australian standard that came into force in 2000 is for 230V +10% -6% , so that is 216V to 253V

however in true bureaucratic madness each state can have it's own regulations, thus in NSW it is 240V +/- 10% ie from 216V to 264V

in practice well designed equipment should handle +/- 10%. In modern solidstate equipment that has internally regulated supplies, a high mains voltage will make the PSU run hotter, a low voltage could make the PSU drop out of regulation and you'll get hum/buzz in the audio. With tube equipment...all bets are off. A lot of tube gear really only works at it's optimum mains voltage. Thus a lot of the old european gear designed for 220V really does want 220V to perform at it's best and also not wear out the tubes excessively.

Rob

[JulienG]

a high mains voltage will make the PSU run hotter

Too true, I was amazed at how cool all my switchmode gear was when I did my trip to the US last year. Normally my laptops power supply gets uncomfortably hot after a few hours, but in the states it was just a degree or two above room temperature.

Also good on-line UPS can often be set to different output voltages, at the place I listed as "two offices ago" we had it set to output 230v which worked fine even when connecting gear like modems that wasn't powered through it.

[Howard Jones]

Hi Smash,

Here's a brief overview. Equipment with switched mode power supplies are probably going to be okay. Equipment with linear regulated power supplies aren't going to be terribly happy with the overvoltages, as these will make the regulators run hot. This will likely bring them into a degree of thermal stress which the designer didn't anticipate. Some power supplies will end up failing under these circumstances.

Any designer sitting down to knock out a power supply circuit has to make some reasoned assumptions. One of these is going to relate to the mains voltage. When the mains voltage goes high, it probably goes outside the design parameters that the designer assumed, which means that the power supply will not be in its safe operating area.

Bear in mind that quite a few power supply circuits seem pretty poorly designed. Even for working at 240V, they run hot and offer poor regulation. If you then shove 260V in, such supplies are going to be even more marginal in their performance. As Rob has pointed out, valve circuits aren't going to be happy at all.

The results of power supply failure (apart from the inconvenience) are variable. Most switch mode power supplies these days are OEM modules that aren't worth repairing. You swap them out, the cost isn't high and away you go. That said, some manufacturers design their own switchmode circuits and then, even worse, include them on the same PCB as the audio. These usually turn out to be difficult and expensive to repair.

Failure in a linear power supply is usually more straightforward to sort out.

This thread could lead on to larger discussions. One topic of which studio users seem mostly unaware is that US-sourced equipment with linear power supplies which can be selected for 110 or 220V operation will invariably have transformers that are made for 60Hz i.e. they have less iron in the core than a transformer made for 50Hz. This means that they run just that little bit hotter at 50Hz and, over many years, this takes its toll – they fail. It’s then a question of having the transformer rewound.

Howard

[Thirteen]

Sadly I often have to fix switch-modes because lots of old gear that I repair has them inside. Fast-recovery diodes often fail, as do electrolytics. Not fun at all.

[smash]

Hey Guys,

Thanks for the responses.

When the Energy Australia tech came out he basically said that the power issues had to be
specific to our house, as no one else had complained in the street. I don't necessarily believe
this, as I think that more than likely I'm the only one in the street that has a live voltage readout
of the mains.

Anyway what was interesting was at the time that I called them, I was seeing regular fluctuations,
moving between 250 and 260 Volts, and also seeing some slight shifting of the phase frequency
also.

About 1 hour after I complained, everything suddenly cleared up with the end result that even though
my power is still over voltage, (255 V) it has been rock solid, with neither the voltage or phase frequency
changing by even 1 point.

I've set the UPS to output at 220 V, so hopefully I'll be out of trouble. It's just a shame I didn't realise before
I blew up another cinema display (3rd so far this year), and the amp for my 5.1 system.

[rick]

my house used to sing to me through the power points due to the offpeak hot water tones , i complained to energy australia who thought i was clearly mad
after several attempts i gage up and wrote a magazine article about it .

the month after the magazine article came out i noticed some guys had turned up out the front of my house and were putting and put a new black box on the power lines right out side my house , "what are you doing ..?" i asked , "maintance " they said ....

when i got home , guess what..? my house did not sing anymore !

the power of the press .. !

now if i can be bothered writing about the fluctuating power at my studio
who knows...?

[Jeremy H]

If anyone's got some extra volts, I know some people out here in the sticks that'll take 'em.

For a number of months at my previous address, we were only getting 205 - 210. Until the transformer down the road spectacularly blew up one night. After they replaced it - things got better.

But still, most of the problems around here are about too few volts not too many...

[rob]

and as it often turns out in life i was pottering in the front yard today and happened to look up at the power pole on the corner of my block. I noticed that the timber crossbeam supporting the 4 mains cables had snapped in half and is kind of just hangin in there. So now i'm about to get onto the power dudes before that lot comes down and falls across my phone/modem lines before landing in my yard, probably killing the cat and dumping a big surge through my house and workshop...

[heathen]

my house used to sing to me through the power points due to the offpeak hot water tones , i complained to energy australia who thought i was clearly mad
after several attempts i gage up and wrote a magazine article about it .

the month after the magazine article came out i noticed some guys had turned up out the front of my house and were putting and put a new black box on the power lines right out side my house , "what are you doing ..?" i asked , "maintance " they said ....

when i got home , guess what..? my house did not sing anymore !

the power of the press .. !

now if i can be bothered writing about the fluctuating power at my studio
who knows...?

I remember that article Rick, funny thing was I thought hmmmm yeah right, then 1 night I'm sitting up late about 2am everything is dead quiet and I could hear an odd chirping sound, it was coming straingt from the power outlet, was only just noticable but I immediately remembered your article on it. I thought geez it's true.

We used get brownouts occasionally, something must have blown up and they must have fixed it though.

[rachelp]

I have heard the singing off peak tones, very late at night. In the new place here, it doesn't do it. My partner used to think I was mad
that I heard this weird beeping, but then I showed him Rick's article and now he believes me!

I don't know if this helps or not, but when we moved in, I got a dedicated 15 amp power point put in, on its own circuit. It seems
very stable. I have these ART power distributors in my rack cabinet and they show a rock solid 244 volts all the time.

We live right near a hospital and I do not know if that has anything to do with it. Occasionally the TV gets a lot of
static on ABC, which we put down to some sort of MRI machine or similar.

One more thing - fridge lights. I was in my studio one night and I heard this buzzing, static noise coming
over the speakers not on the 15amp line. 20 minutes later I went down and flick onthe telly and there
was static on several channels. Then I went to the fridge and discovered the door just open enough
to leave the light on - open the door, no static. Close the door, no static. Open the door just right - lots of static!


rachel

[rick]

heathen
how could you doubt me , it was such a screw up of an article - who could be bothered making that shit up ..?

the next one might read like this

my little boy used to have a small fuzzy little cow toy it made a few different noises depending on which part of its body you pressed.
the damn thing also "reset itself " from time to time at about 3am ( i guess thats when things got cold enough to freak out the batteries)

after about the third night of me waking up to a faint little "reset" melody i jumped up tracked down the offender which just happened to be down deep in a pile of his toys .
when figured out it was a kids toy and it was resetting itself , well lets just say there is one less fuzzy toy in our house !
apparently people normal people sleep through random bleeps because they figure its nothing to do with them :)

actually there was only one less toy for about 24 hours because kids toys just seem to multiply around my home.

which reminds me next time i see his new jet aeroplane toy , i am going to see what i can do about "repairing the takeoff noise " its a little 2 bit sample at about 400 % distortion and he just loves it , but now the speaker broken and is buzzing - it drives me nuts

[heathen]

heathen
- who could be bothered making that shit up ..?

Agreed. :)

[rob]

phoned the power dudes first thing yesterday to report the crossbar on the stobie pole out the front was cracked. My expectation ( bolstered by the bored response from the phone operator ) was that nothing much would happen to fix it for ages. Thirty minutes later with my head inside a TR808 all the power goes off ( which in a workshop always causes me to leap about looking for the smoke ). After a quick check of the circuit breakers and RCD on the wall next to me which were all ok, i headed out the front to find an arc of orange cones around the stobie pole and crew beginning to drop the cables to replace the crossbar.
I was told this would take about an hour and a half...damn there is nothing i can do in my workshop without power, this was going to put a hole in what i'd planned to be a productive day's work. Then i remembered i was the one who called them and could hardly complain about the prompt service.
So i sat out in the sun, ate an apple and read AT for while....

[TimS]

phoned the power dudes first thing yesterday to report the crossbar on the stobie pole out the front was cracked. My expectation ( bolstered by the bored response from the phone operator ) was that nothing much would happen to fix it for ages. Thirty minutes later with my head inside a TR808 all the power goes off ( which in a workshop always causes me to leap about looking for the smoke ). After a quick check of the circuit breakers and RCD on the wall next to me which were all ok, i headed out the front to find an arc of orange cones around the stobie pole and crew beginning to drop the cables to replace the crossbar.
I was told this would take about an hour and a half...damn there is nothing i can do in my workshop without power, this was going to put a hole in what i'd planned to be a productive day's work. Then i remembered i was the one who called them and could hardly complain about the prompt service.
So i sat out in the sun, ate an apple and read AT for while....

Take that well earned breather Rob!!
AT was a good read this edition - I'm still wading thru it..
T..

[JulienG]

So i sat out in the sun, ate an apple and read AT for while....

Rob, you need to learn to justify like a staff engineer.

You didn't "read AT for a while" you "Researched industry news and trends" :-)

[Kris]

Rick, I have the same problem here. Tigger just goes bouncing by himself (on a wooden floor no less) at all sorts of ungodly hours. Not to mention singing his Tigger song.

We also have been "loaned" some toys with reaaaaallly annoying american women singing animal songs. I swear we were given them because the original owners got sick of the noise.

[heathen]

My VB Warney would do the same thing , I'm so glad the battery has run out.

[TimS]

We have lots of kids toys that need batteries. :(
I use a battery recharger, so when they die, I just leave them in until my little man REALLY wants to have the sounds back - otherwise they stay silent for some time - but he's still happy playing with them, sounds or not!!
Phew!!

[astrovic]

Rick, I have the same problem here. Tigger just goes bouncing by himself (on a wooden floor no less) at all sorts of ungodly hours. Not to mention singing his Tigger song.

We also have been "loaned" some toys with reaaaaallly annoying american women singing animal songs. I swear we were given them because the original owners got sick of the noise.

I think we've got the same Tigger. Never seen or heard him self-bounce, but that might be because my 2yo daughter loves to fire him up, then pin him to the ground suppressing his bounce until he goes a little weird. I think he's scared witless now.

The stupid thing is, she plays for minutes with all these battery operated doodads, and hours with the simple stuff like jigsaws, colouring books, wooden trains etc etc. I think she takes after me - must have [insert latest music gizmo here], put on pile and go and play acoustic.

[TimS]

Sounds like we ALSO have the same Tigger - bouncing and saying "your a tiggerific bouncer, come on, bounce with me" - with a lisp!!
Ha!! :)

[astrovic]

Sounds like we ALSO have the same Tigger - bouncing and saying "your a tiggerific bouncer, come on, bounce with me" - with a lisp!!
Ha!! :)

Let's bounce again - wanna?

[TimS]

Sounds like we ALSO have the same Tigger - bouncing and saying "your a tiggerific bouncer, come on, bounce with me" - with a lisp!!
Ha!! :)

Let's bounce again - wanna?

hahahah - yep, thats the one - so cute!!

[rachelp]

I hate that chuddering sound mobile phones make when there is a signal coming in from somewhere.

We've learnt to keep our mofos away from anything with a speaker.

(ob tigger) TTFN!


rachel