Voltage Change US/UK

[ebarker2]

I'd like to run a US made amp in the UK, though the amp which still retains its 110 volt transformer and the UKs grid is 220 volt. Will using an outboard voltage adaptor degrade the sound quality? If so how complicated would it be to change transformers?
thanks

[sreten]

First check how many primaries the transformer has. If it has
two wired in parallel you simply wire them in series for 240V AC.
(Do not get these the wrong way round ! i.e. out of phase.)

A large autotransformer some would argue improves the quality.
An autotransformer not big enough will make it sound worse.

Changing transformers is not too difficult but you need a decent
sized soldering iron, be able to solder properly and reinstate the
wiring to the relevant insulation standards, e.g. shrouded mains
connections.

sreten.

[Tube_Dude]

Originally posted by sreten


A large autotransformer some would argue improves the quality.
An autotransformer not big enough will make it sound worse.

Better than a autotransformer is a normal transformer...because it can provide some comum mode noise rejection!!

[eeka chu]

The UK mains runs at about 240V.

I am just looking thru my Fluke scopemeter at the moment. There is a REALLY funny trace on here. A while back, I noticed the lights seemed to be flickering a lot. So I connected the scope to the mains and left it recordering for a while. The flickering got steadily worse.

I'm now looking at a trace where the mains was flickering !40! volts -. It did this for about an hour or so almost continuously. The maximum peak was 245.2V~ RMS.

The second trace just looks like a wide black blur.

I'm holding onto the two traces I took just to prove that there is a use for supply regulation!

[Cybergent]

Afaik UK Power is rated at 230V.

But you are right, they have a lot of variation on it. We know it from our English customers. So you might look into a mains voltage between 210 and 245 volts.

[eeka chu]

I heard a few years ago that they where meant to be changing it all to 230V. I'm not sure how far that has actually been implemented though. It always seems to be about 240V. Perhaps they need to update the substations and such.

The UK mains is currently not in a very good way. It was privatised and is now supplied by a number of commercial stations. The governement have said that are not planning to build anymore nuclear or coal fired stations.

Considering the age of some of the stations in the UK, this means that the nuclear and coal stations are soon to become out dated technology. I think the last nuclear station was built around a decade ago, but I'm not totally sure about that. I actually remember hearing something about the newest coal fired station having been built in the 70's. Since reactors need replacing every 20 years, there is a finite amount of time left.

This leaves gas and oil fired stations. We mine oil and gas in the North Sea, which is predicted to fail as a resource soon. So, in turn, we will be left buying oil and gas directly from countries in the East / Middle East. Eirely ironic & coincidental considering recent events!

The current line of thought is to go green! With a massive <10% of the power in the UK coming from renewable resources and a total of !3! hydrogen powered buses in London only, we're practically there already.

When the mains was supplied by government run stations, regulation required a minimum of 15% spare capacity. Now the mains has been privatised, spare capacity can be measured in single figures.

Last year a shut down coal fired station had to be rapidly started again because the mains was cutting off altogether. Restarting an entire power station obviously insn't an easy thing to do.

The UK mains sure isn't very smooth at the moment!

Saying that, I haven't looked at what other grid capacities are like in comparison. One two hour long power cut in a long, long time isn't what I'd call a life threatening event myself. It seems everyone in London thinks it is though.