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US/UK mains voltage and frequency - how much of an issue is it?

Discussion in 'AV Receivers & Amplifiers' started by NicolasB, Mar 26, 2003.

  1. NicolasB

    NicolasB
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    There has recently been a proliferation of old Bryston equipment selling at outrageously low prices on Ebay - well under $1000 for a 4B-ST. I've been mildly tempted, but obviously Bryston models have different power supplies depending on whether they are intended for the US or UK market. (This is not true of all brands. Lexicon processors, for example, have universal power supplies, IIRC).

    This leads to me wonder about the general case: where processors and amplifiers are concerned, how much of an issue is mains voltage and frequency? I'm not suggesting one should just plug a device intended for a 110V supply into a British mains socket and hope ;) but obviously one can buy step-down transformers, which should at least supply the correct voltage. But do these add noise to the mains signal? Do they allow as much current through as you might expect to come out of an actual american mains socket? Is the 50Hz/60Hz frequency difference an issue? And how much does one have to pay for a step-down transformer that really does the job?
     
  2. siluro

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    Hi nic, as far as i know 50/60hz sinewave of mains power here/states isnt the bigest issue, basicly...

    here we have 220/240v with pretty low current and the states has 110v but the current pulled by the same device here could pull half as much again in the states (specialy a large amp like the bryston)

    no matter what a transformer for this kinda job will enduce some mains interferance (due to large currents) but, wot you would save on the amps your going to more than make up in transformer cost, which would most likly have to be made specialy running in to what could be a few hundred plus. but youlve also got to consider the safety issue with stepping down and pulling heavy current.

    unless you could find some actual uk power supplys from a uk bryston

    i might be wrong, but im pretty thats right

    cheers
    lee
     
  3. nathan_silly

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    I would only use low current devices from the states- DVD players etc, and not poweramps. No doubt a stepdown with 300W + output will cost £100+

    I know my brothers Pioneer 606 trips the £15 stepdown after a few hours, I guess it's higher power consumption than my Sony (no probs with the same stepdown)
     
  4. alexs2

    alexs2
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    You obviously need to ensure the transformer is suitably rated to ensure it doesn't get too hot(!) or strangle the power supply,and usually these devices,especially in the power amplifier rated range,are very expensive.

    If you want the best,you could take a look at www.isotektechnologies.com for a range of very high quality isolation transformers with the capability of stepping down voltage for US gear,but as I said earlier....not cheap,you're looking at up to £2k for the sort of transformer you will need for that power rating.

    There are numerous other options,and HiFi News ran a series of articles on isolating transformers...the link to that is http://www.britishaudio.co.uk/PPFLY.html and you will find this substantially cheaper than Isotek's products,and very well made also.....around £500.
     
  5. daninthemix

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    Nic - I agree with the above. Low power devices are okay; if the power supplies are suitably decent (which they are with this level of kit), there'll be little performance penalty using a step-down.

    Power amps on the other hand are a BAD IDEA as the step-down will raise impedance to intolerable levels and generally suck all the life and dynamics out of the sound. I know this because I used to use a PS Audio power plant (600 watts) - certainly not too shabby, but plugging straight back into the mains was an absolute revelation - 'alive' is the best word i can come up with at the mo.
     
  6. alexs2

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    Thanks for that comment,dan.....certainly helped convince me not to eventually go down that route....will stick to decent mains supply and good cables!
     
  7. NicolasB

    NicolasB
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    The manual for my Bryston 9B actually explicitly tells you NOT to use any sort of mains conditioner with it, although it doesn't really go into the whys and wherefores.....
     
  8. daninthemix

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    Almost certainly for reasons stated by me above. Now, on a more important note: what happened to the scruffy old cat avatar? It was fantastic!
     
  9. NicolasB

    NicolasB
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    My previous avatar made me feel a bit of a fraud. Although it was obviously supposed to be a picture of Bagpuss, it was, in reality, a scale-down of a rather poor digital camera shot taken by somebody else a couple of years ago of a replica toy bagpuss that I had bought as a Christmas present for someone. If I could find a decent photo of the real thing I might go back to it.

    But in the meantime I prefer to be a Dungeon Master rather than a Saggy Old Cloth Cat. :)
     
  10. John Dawson

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    For the record it is technically not advisable to use equipment intended for 60Hz mains on a 50Hz supply - particularly power amps. The transformer cores need to be a lot bigger to handle 50Hz without saturation and I suspect (but of course am happy to be corrected) that Brystons sold in North America do not have 50/60Hz capable transformers. So if you use them in the UK, even with an auto transformer to generate the 120VAC line, the transformers in the amps will run quite a bit hotter than usual and will be a lot more susceptible to buzzing too.

    OTOH equipment designed for 50Hz mains has quite a bit in reserve when run on 60Hz.

    John Dawson (Arcam)
     

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