Mains voltage & European market units - again!

[Pete The Cat]

I'm sure this has been asked before but recall that there were some diverging views. My mains seems to run towards the 250v mark on average. I need to put a replacement Exposure XVII into service and it’s a former Italian 220v version.

I’m familiar with the story behind EU mains voltage “consolidation” and how the 230v standard with a margin of tolerance that we read on labels is a bit of a hedge between ongoing 220 and 240 continental v UK grid levels.

This all suggests to me that the unit won’t experience anything drastic if I use it here but that it will run warm and its overall lifespan may be shorter. If so I’ll live with that, but if it’s likely to explode or cause consequent damage to other pieces of kit I wouldn't chance it.

On the back of old Exposures there's an area that's manually marked to show which voltage applies to that particular unit. Clearly they recognised a difference because the label shows every option from 110 to 240, and 220 is the one that is not crossed out.

I won’t hold it against anyone if it goes wrong but this place is an oasis of good advice so I await refreshment.

Pete

[awkwardbydesign]

How much current does it draw? I use a 2 amp variac for my 2 Ming Da 845 SET monoblocks, as they need 220v. Or do this, I intend to at some point, but it's not urgent for me; variac! http://www.dms-audio.com/bucking-transformer-diy

[Firebottle]

Now that's an excellent idea, and simple too :)

:cool: Alan

[UV101]

I think I'd prefer to go down the regulated heater route and run the HT a little hotter!

Not sure I'd want anything potentially restricting the mains input flow. Is 2a enough and it would be via a wiper contact in the variac? A 50va 230-220 transformer shown in the link will only give you 440mA which I suspect will be a bottleneck.

With respect to the original post, assuming all the caps on the supply rail are rated and able to cope with a few extra volts it will be fine. The only way you will find out is to measure the voltage and check that's its below the voltage rating for the main psu caps and any other caps attached directly to the +/- rails. There will be voltage regulators for any low voltage stuff going on but not for the main output stage.

[Reffc]

I think that Italian mains voltage was 240v the same as ours here in the UK. If it is an Italian built amp made for Europe, and was built since 2004 mains harmonisation, then it should be rated at 230v athough if built for a particular European market cpre 2004 could be 220v. The guidelines state that all mains for EU countries should conform to 230v -6%/+10% and 50 hz. the voltage standard is a fiddle factor since the UK and Italy are both rated as 230v but we operate at 240v.

The use of a 220v power supply for UK 240 mains is generally not a good idea but it depends on the design of the transformer.

I use a unit like this one: http://upsmart.co.uk/ag1500-regenerator-1500w-psu-p-1742.html

...partly because its cured the hum I had on all of my amps transformers as well as eliminated ground loop issues and partly because it ensures that my Gyro runs at a consistent speed (mains here fluctuates between 235 and 245 volts). Running a 220v transformer at 230v should be absolutely fine.

You can also use a step down transformer (try RS online) which is the cheaper option (around £50?).

[Ali Tait]

Open the lid and have a look at the trannie, there may be tappings for the various voltages. If so, move it to the 240 one.

[awkwardbydesign]

I think I'd prefer to go down the regulated heater route and run the HT a little hotter!

Not sure I'd want anything potentially restricting the mains input flow. Is 2a enough and it would be via a wiper contact in the variac? A 50va 230-220 transformer shown in the link will only give you 440mA which I suspect will be a bottleneck.

With respect to the original post, assuming all the caps on the supply rail are rated and able to cope with a few extra volts it will be fine. The only way you will find out is to measure the voltage and check that's its below the voltage rating for the main psu caps and any other caps attached directly to the +/- rails. There will be voltage regulators for any low voltage stuff going on but not for the main output stage.
There a bigger variacs. I only gave the current rating of mine as an example; likewise with the bucking transformer. My amps are class-A SETs, so no sudden current surges, and the bucking transformer is only dropping 20v, although I would over-rate it anyway. I daren't run mine at 240v, as we are talking of over 1000v to the HT.
The advantage of a variac, is that it is easy to fit, adjustable, and can be used for other things too.

[Pete The Cat]

8380

Thanks for all of your insights.

This tells me not to just change the plug and give it a whirl.

A delve inside suggests that it was manufactured in the UK (unless Exposure had an Italian plant with employees called Ian and Michael :eyebrows:) in October 1993. There's a nice chunky transformer yet no helpful writing on it.

From here, before I invest in a voltage converter I'll play it safe and get a professional to check it out first.

Your time and help has been appreciated - cheers :cool:

Pete