+ Reply to Thread
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 27

Thread: mains Voltage

  1. #11
    Join Date: Feb 2008

    Location: South Wales

    Posts: 9,151
    I'm NotTakingLifeTooSeriouslyTheseDays.

    Default

    Unfortunetly,these days most equipment [Still using a normal mains transformer, not switched mode] designated to be used within the EU' is supplied with a power transformer that is designed for 230v, the theory is; that it should work fine between 220v, and 240v, however, a lot of the equipment I have had in for repair, and tested needs only 220v, and sometimes less to work optimally, so in theory, it has at least 20v over what the equipment is designed for!
    "Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
    Nikola Tesla



    Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
    A fish is only as healthy as the water its swimming in ! [Dr Robert Young]


    www.tubedistinctions.co.uk

    Matthew 5:10

  2. #12
    Join Date: Feb 2013

    Location: W Lothian

    Posts: 99,005
    I'm Grant.

    Default

    Ive used a few 220v things and found 230v is fine. 240v isn't. either a regenerator or a bucking tx/variac are needed.
    Regards,
    Grant .... ؠ ......Don't be such a big girl's blouse

    I've said it before and I'll say it again: democracy simply-doesn't-work
    .... ..... ...... ...... ................... ..... ..... ..... ..... .....
    FIIO K7 BT, M11 PLUS, BTR7, KA5 - OPPO BDP-103D - PANASONIC UB450 - PANASONIC 4K ULTRA HD TV - PIXEL 6 - AVANTREE LR BLUETOOTH - 2* X600 SOUNDCORE - HEADPHONES INCLUDE, FIIO, NURAPHONES', FOCAL, OPPO, BOSE, CAMBRIDGE, BOWER & WILKINS, DEVIALET, MARSHALL, SONY, MITCHELL & JOHNSTON - 2*ZBOOK'S- MERCURY BD ROM, ROON, QOBUZ, TIDAL, PLEX, CYBERLINK, JRIVER - MULTI HDD'S -

    Oh my god! There's nothing wrong with the bidet is there?

    “Nothing discloses real character like the use of power. It is easy for the weak to be gentle. Most people can bear adversity. But if you wish to know what a man really is, give him power. This is the supreme test. It is the glory of Lincoln that, having almost absolute power, he never abused it, except on the side of mercy".

    “You see these dictators on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police ... yet in their hearts there is unspoken fear. They are afraid of words and thoughts: words spoken abroad, thoughts stirring at home -- all the more powerful because forbidden -- terrify them. A little mouse of thought appears in the room, and even the mightiest potentates are thrown into panic.”

    "You don't have free will. You have the appearance of free will.”

    “There's a war out there, old friend. A world war. And it's not about who's got the most bullets. It's about who controls the information. What we see and hear, how we work, what we think... it's all about the information!”


    ***SMILE, BE HAPPY***

  3. #13
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

    Default

    Steve, you could contact Airlink, who should be able to supply a balanced mains transformer with 220v output. Be cheaper than a mains regen unit.
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  4. #14
    Join Date: Feb 2008

    Location: South Wales

    Posts: 9,151
    I'm NotTakingLifeTooSeriouslyTheseDays.

    Default

    Good sugestion Ali.
    A...
    Quote Originally Posted by Ali Tait View Post
    Steve, you could contact Airlink, who should be able to supply a balanced mains transformer with 220v output. Be cheaper than a mains regen unit.
    "Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
    Nikola Tesla



    Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
    A fish is only as healthy as the water its swimming in ! [Dr Robert Young]


    www.tubedistinctions.co.uk

    Matthew 5:10

  5. #15
    RothwellAudio Guest

    Default

    You could fix the buzzing in the headphone amp by stopping its mains transformer from rattling. Basically the laminations that make up the transformer core are rattling/chattering as they are magnetised by the mains. Sometimes you can tune out the rattling by adjusting the tightness of the screws which are holding the transformer laminations together. Sometimes the transformer hasn't been potted well - maybe not all - but you can still do something about that. Transformers are dipped in varnish to pot them. You could do the same, or maybe even just drip some varnish on the top so it soaks into the laminations. Use oil-based varnish, not the modern "quick drying, low odour" water-based stuff.

    It's possible that the problem isn't so much the high mains voltage as an effective DC component on the mains.
    This explains it: http://www.isol-8.co.uk/dc_on_the_mains.html

  6. #16
    Join Date: Feb 2008

    Location: South Wales

    Posts: 9,151
    I'm NotTakingLifeTooSeriouslyTheseDays.

    Default

    Yes,agree, Noise, and DC element on the mains can cause transformers to sing along with the mains, especialy toroids, and it can be worse at diffrent times of the day, this is definitely something to be considered!
    Quote Originally Posted by RothwellAudio View Post
    You could fix the buzzing in the headphone amp by stopping its mains transformer from rattling. Basically the laminations that make up the transformer core are rattling/chattering as they are magnetised by the mains. Sometimes you can tune out the rattling by adjusting the tightness of the screws which are holding the transformer laminations together. Sometimes the transformer hasn't been potted well - maybe not all - but you can still do something about that. Transformers are dipped in varnish to pot them. You could do the same, or maybe even just drip some varnish on the top so it soaks into the laminations. Use oil-based varnish, not the modern "quick drying, low odour" water-based stuff.

    It's possible that the problem isn't so much the high mains voltage as an effective DC component on the mains.
    This explains it: http://www.isol-8.co.uk/dc_on_the_mains.html
    "Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
    Nikola Tesla



    Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
    A fish is only as healthy as the water its swimming in ! [Dr Robert Young]


    www.tubedistinctions.co.uk

    Matthew 5:10

  7. #17
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

    Default

    Yes indeed. Steve, if you go the Airlink route, get them to fit a DC blocker to the input.
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  8. #18
    Join Date: Jan 2009

    Location: Essex

    Posts: 31,859
    I'm openingabottleofwine.

    Default

    In times past electronic gear used to be fitted with mains voltage selectors which selected the appropriate tapping on the transformer primary. This was because the transformers used were designed deliberately to be run close to saturation to improve regulation. If extra turns were wound on the primary to increase the saturation margin, the increased resistance would result in poorer regulation.

    When a transformer saturates the inductance falls and the primary current rises. Saturation can be caused either by running the primary on too high a mains voltage or by having some DC on the mains (which is effectively is similar, but only occuring each cycle, rather than every half cycle). It only takes ~100mV of DC offset to cause toroidal transformers to buzz (owing to a lack of air gap in the core, toroidals 'hard limit' when saturated).

    Early power supplies were unsophisticated, so it was important not to compromise regulation, but modern regulated power supplies can be supplied with a transformer that has a much larger saturation margin, and hence no need for a mains voltage selector.

    However regardless of the margin of saturation, if the laminations are loose they will buzz, simply due to the AC nature of the mains supply.
    Barry

  9. #19
    Join Date: Feb 2008

    Location: South Wales

    Posts: 9,151
    I'm NotTakingLifeTooSeriouslyTheseDays.

    Default

    Quote Originally Posted by Barry View Post
    In times past electronic gear used to be fitted with mains voltage selectors which selected the appropriate tapping on the transformer primary. This was because the transformers used were designed deliberately to be run close to saturation to improve regulation. If extra turns were wound on the primary to increase the saturation margin, the increased resistance would result in poorer regulation.

    When a transformer saturates the inductance falls and the primary current rises. Saturation can be caused either by running the primary on too high a mains voltage or by having some DC on the mains (which is effectively is similar, but only occuring each cycle, rather than every half cycle). It only takes ~100mV of DC offset to cause toroidal transformers to buzz (owing to a lack of air gap in the core, toroidals 'hard limit' when saturated).

    Early power supplies were unsophisticated, so it was important not to compromise regulation, but modern regulated power supplies can be supplied with a transformer that has a much larger saturation margin, and hence no need for a mains voltage selector.

    However regardless of the margin of saturation, if the laminations are loose they will buzz, simply due to the AC nature of the mains supply.
    "Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
    Nikola Tesla



    Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
    A fish is only as healthy as the water its swimming in ! [Dr Robert Young]


    www.tubedistinctions.co.uk

    Matthew 5:10

  10. #20
    Join Date: Aug 2012

    Location: North East

    Posts: 3,670
    I'm Steve.

    Default

    A lot for me to think about here folks. Many thanks.

+ Reply to Thread
Page 2 of 3 FirstFirst 123 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •