Go home, Norfolk Mains Electricity, you're drunk. And lairy.

EdGrip

I knew that custom transformer for the Princeton was a good idea.

imalone

Free volts!

Cirrus

We have a similar problem in Birmingham on occasion.

I built this for my AC30;

chillidoggy

EdGrip said:

I knew that custom transformer for the Princeton was a good idea.

Oh, it's VOLTS on the display. I thought that was the latest bill.

imalone

Of course there's the question of what the calibration on that meter...

holnrew

Maybe it's measuring the peak AC voltage rather than the thingybob that's 230. Can't remember the name but it's a calculation of the DC equivalent.

imalone

Root mean square. The factor is 1/sqrt(2), and peak would be about 340V (or 368V in this case!). So far as I know an A/C meter will always report RMS.

holnrew

Yeah it's not that then.

BigMonka

Have you notified them as it's outside the +10% -6% bounds of the The Electricity Safety, Quality and Continuity Regulations 2002. Although as previously said the calibration of the monitor could be questioned but it should be enough evidence for them to investigate.

PolarityMan

maybe it's measuring the distance to the nearest sandwich

Moe_Zambeek

You must have Russ Andrews grade gold plated unicorn hair mains cables.

Have you noticed your mids being any more haunted recently?

chillidoggy

I'm wondering if this is what's wrong with my toaster - voltage too high.

EdGrip

I'd say the mids on my amp are haunting, but my toaster is definitely haunted. 

My Fluke matches that thing. I haven't notified them. I probably should. That's the worst yet, though.  

ICBM

It could be *just* within the legal maximum (253V) if the meter has a 3% error, which is not uncommon for cheaper ones - but even then the meter would have to be at the outer end of the tolerance as well, so I'm pretty sure the true voltage is over the limit. And certainly so if the Fluke gives the same reading, even their basic models are 1% I think.

It's like that at a studio I do some work for, and they have complained - an electricity company man came round, stuck his meter on it and said "it's fine, it's 253 volts". NOT fine! Especially as it varies during the day and the time it was measured is not when they get the highest voltage. I did suggest they asked to see the calibration certificate for the meter but they didn't really understand what I meant...

So much for the "European harmonised 230V" that we supposedly get.

Rocker

Cirrus said:

We have a similar problem in Birmingham on occasion.

I built this for my AC30;

@Cirrus, what exactly does that little box do?

Cirrus

It takes off either 12 or 24 volts from the mains power going into the amp. Basically there's a little 12v transformer in there, and by wiring it out of phase with itself you can get it to shave off some voltage passing through it.

Phil_aka_Pip

Cirrus said:

It takes off either 12 or 24 volts from the mains power going into the amp. Basically there's a little 12v transformer in there, and by wiring it out of phase with itself you can get it to shave off some voltage passing through it.

I'm intrigued. Any chance of a schematic?

ICBM

http://sound.westhost.com/articles/buckx-f3.gif

Make sure you connect the secondary winding the right way round or you'll end up with boosted output voltage instead of reduced .

Rocker

Why wire the transformer primary? Simply wire the secondary in series on the live? Or am I missing something obvious, thanks @ICBM or @Cirrus

ICBM

Rocker said:

Why wire the transformer primary? Simply wire the secondary in series on the live? Or am I missing something obvious, thanks @ICBM or @Cirrus

You need the primary to generate the voltage in the secondary. Without that, it would just be a choke in series with the load, and barely reduce the voltage.

Essentially you've created an auto-transformer, and because the secondary is physically separate and capable of being reverse-phased it can be on the output side, rather than the usual arrangement with the input being the full coil and the output being the tap. I'm pretty sure using the secondary like that allows a much smaller core size for the same power transfer as well, but I could be wrong.

Cirrus

The main thing is, when you're wiring it up don't accidentally bridge the live and neutral wires with a multimeter probe, because then the whole house goes dark and your partner gets very cross with you. And you need to buy a new multimeter probe too, which is even worse!