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Thread: Tweaks

  1. #1
    Join Date: Sep 2014

    Location: Istanbul

    Posts: 115
    I'm Yetkin.

    Default Tweaks

    May be you saw before but I could not found in art of sound forum, it shall be in your interest, two different tweaks recently catched my and my local DIY guys attention.

    After making two and some listening tests aggreed that both works.

    1) broskies ground isolator between plug ground and chassis ground.
    2) Battery Ground Tweak


    Both of them are very simple things

    1) 10 ohm resistor+0,01-0,1 uF capacitor + bridge rectifier in paralel
    Plus side of the bridge rectifier will be on the power socket Side.
    Here is the logic


    New House-GND Kit


    
The wall outlet's third jack connects to the house ground, which is also known as "earth," as the house ground is often created by attaching the wall socket's neutral connection to an 8-foot metal rod buried in the dirt under your house or to the cold-water pipe, assuming that the pipe is made of metal. Many old houses and apartment buildings do not offer a connection to the house ground, only the two power wires, which is unfortunate, as the a connection to the house ground is a safety feature.
    For example, say that something goes terribly wrong in your power amplifier and the B+ attaches to the chassis. Well, if the chassis does not make a connection to the house ground, you could receive a lethal shock from touching the energized chassis. But with a solid connection made to the house ground, the B+ voltage would drain away safely.
    The big problem for us audiophiles is that house ground often becomes contaminated by other electrical devices in your house. This could be avoided, if when they laid out the house wiring, each wall socket got its own separate house-ground wire that in a star-grounding fashion traveled independently back to the houses fuse box and its ground connection. But as this excellent setup would require much more wire, it is seldom performed; instead, most house-ground connections daisy chain their way back to the electrical panel's house ground, much like Christmas-tree lights strung in series. Some electrical equipment is miswired internally, so the neutral and house-ground connections are reversed. This causes something which should never occur: the house-ground wire seeing a sustained current flow.
    (Ham-radio operators face much more dangerous situations, as lightning can hit the transmitting antenna and then travel through the house wiring until it hits the house ground, setting your house ablaze along the way.)
    How do you know if you have a dirty house ground connection? Simply attach an AC volt meter to the neutral and house ground connections on the wall socket and read the voltage. It should read 0V. In my listening room, it doesn't, as there is a 500mV AC voltage difference between the two. Is that a problem? Not if you plug a lamp or a toaster into the wall socket, but it is if you plug in some audio equipment, as the resulting hum testifies loudly.
    The workaround is to use* the following circuit.

    The diode bridge only connects the two grounds when the voltage difference between them exceeds about +/-1.4V. The capacitor allows high-frequency noise to find a path to the house ground. The 10-ohm power resistor makes a DC connection between grounds, while still offering some isolation between grounds.

    2) Battery ground Tweak ( BGT ) is also simple
    9v Battery with min 22000 uF electrolytic cap and min 0,1 uF by-pass cap in parallel
    1 wire to solder on (-) pole
    And connect it to any empty (-) rca input of CD, dac, pre etc.
    It works with speaker as well ground line input

    Changing the electrolytic cap and especially by-pass cap changes sound
    9 v is ideal above 9 v makes upper frequencies too front,

    Original idea came from Bud Purvine diyaudio forum. But upgraded by some others

  2. #2
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,202
    I'm Chris.

    Default Very Bad advice, don't do this

    Hi
    Deliberately breaking chassis ground connection on equipment
    that is not double insulated, provides no safety earth and is not only
    dangerous but illegal in most countries.

    think about if a transformer fails ?
    If a wire associated with mains voltage touches chassis.WHAT THEN ?

    It is explained here: http://sound.westhost.com/earthing.htm

    "Should a fault develop within the equipment that causes the active (live) conductor to come into contact with the chassis, the fault current will flow to earth, and the equipment or main switchboard fuse or circuit breaker will blow. This protects the user from electric shock, bypassing the dangerous current directly to earth, rather than through the body of the unsuspecting poor bastard who just touched it. If this experience does not kill, it will invariably enrich the vocabulary"

    Without mains safety earth your chassis and all partnering equipment connected
    if similarly disconnected has no path to safety earth.
    Also voltage ratings appear to be ignored with respect to mains voltages,
    in the capacitor a ceramic of 50v value shown in your image.

    IF YOU HAVE GROUND LOOP PROBLEMS SEEK ADVICE TO SOLVE THEM,
    BUT NOT BY DISCONNECTING SAFETY EARTH.

    Suggestion 2 which is ground lifting has many forms,, read about them in the same article.
    and here: http://diyaudioprojects.com/Technica...ing-Shielding/
    and many advices here: http://theartofsound.net/forum/forum...p?34-Technical

    Cheers / Chris


    .

  3. #3
    Join Date: Sep 2014

    Location: Istanbul

    Posts: 115
    I'm Yetkin.

    Default

    Actually there are 2 different tweaks.
    First was as you pointed out between power socket ground and chassis which was explained how it works by broskie.
    As far as I understand it do not break safety earth.

    Second tweak was aplied directly to rca input terminal from outside whatever terminal is not used. This aplication has nothing with safety earth as I understand.

    Am I wrong ?

    If you point that broskie is not correct and bridge rectifier breaks safety earth this I can not say anything against, as I do not clearly know how 2KBP01 bridge diode works.
    Meanwhile thanks Chris for the two links...
    Last edited by tiguan; 14-12-2015 at 19:05.

  4. #4
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,202
    I'm Chris.

    Default

    Quote Originally Posted by tiguan View Post
    Actually there are 2 different tweaks.
    First was as you pointed out between power socket ground and chassis which was explained how it works by broskie.
    As far as I understand it do not break safety earth.

    Second tweak was aplied directly to rca input terminal from outside whatever terminal is not used. This aplication has nothing with safety earth as I understand.

    Am I wrong ?

    If you point that broskie is not correct and bridge rectifier breaks safety earth this I can not say anything against, as I do not clearly know how 2KBP01 bridge diode works.
    The power socket ground IS the connection to safety earth, breaking it then disconnects the chassis from
    safety earth.


    The second circuit applied to a RCA terminal is then not a proper fitting
    as it attempts to circumvent proper grounding already applying in most
    equipment chassis.

    You need to learn the benefits of Star grounding, as the circuits involved
    with lifting invariably become redundant and are usually a waste of time.
    By using ground lifting, you have almost in every case ignored Star grounding

    Star grounding has benefit to apply to almost every piece of audio equipment
    and is used widely. When currents ( - and there can be many
    individual returns ) are returned individually to a common point, this is
    referred to as a Star ground. From the Star ground point which is
    usually and must include the equipment chassis, connection is then
    made to safety earth. Avoid the star ground wiring being in close
    proximity to transformers.

    Using diode bridges is a very clever way of isolating sections when done properly.
    discussed here: http://www.diyaudio.com/forums/pass-...-question.html

    Ask yourself what happens with a plastic or wooden chassis ?
    With such a chassis having little or no metal, much use of shielding
    around each path using coaxial techniques returning currents can
    achieve excellent result, but a star earth is still used, as is safety earth.

    So study Star earthing, and coaxial cable design and their use, used properly you will
    be designing with real ability to provide excellent audio circuits. Once
    you have mastered star earthing and coaxial cable, look at diode bridge isolation
    followed by opto isolation.

    The ground lift devices you show will then very quickly appear to you, as rubbish
    and little more than an excuse for not applying star earthing correctly.

    Isolation employing opto coupling which can be opto coupled transistors
    light dependant resistors, and transformers, are all further forms of
    preventing ground loops.


    Cheers / Chris

  5. #5
    Join Date: Sep 2014

    Location: Istanbul

    Posts: 115
    I'm Yetkin.

    Default

    Thanks Chris, I will dig it more.

    as it was recommended by broskie I did not questioned that much.

    But as far as I understand, if you are in trouble with ground loop what ever you do, the way to solve with the safest way of doing it is pass or rod elliot's way.


  6. #6
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,202
    I'm Chris.

    Default Diode Grounding

    Hi Yetkin
    Yes the diagram explains it well. A diode bridge is used that should have a voltage
    rating always higher than the peak expected voltage, so use 400v or 1kv, that
    extends what is the diode threshold rating to pass current. The resistor and capacitor
    lower this so called impedance further.

    For circuits that can tolerate slight ground lifting, instead relying on the
    threshold voltage typically 0.6v being present, the attached circuits
    are very useful. Such stages may be then used to isolate grounding functions
    in and around a low current and low voltage circuit.

    As a general rule use just diodes this way with circuits passing no more than 200ma
    and no more than 30v DC. Always use the other providing lower impedance for passing
    higher current and voltage in the case of protecting for equipment fault.

    Note the diode bridge can be used either way, either with +- connected to ground,
    and AC terminals as needed ground inputs or the AC terminals connected to ground,
    and + as one and - as the other needed ground input.

    Cheers / Chris

    Diode Grounding.pdf
    Last edited by Light Dependant Resistor; 15-12-2015 at 22:22.

  7. #7
    Join Date: Feb 2014

    Location: Huntingdonshire

    Posts: 1,413
    I'm Andrew.

    Default

    Who is this Broskie?

  8. #8
    Join Date: Feb 2014

    Location: Huntingdonshire

    Posts: 1,413
    I'm Andrew.

    Default

    John Broskie the tube guy I assume. Seems to know his shizzit but I'm not liking the first tweak and can't see the point of the second.

  9. #9
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,202
    I'm Chris.

    Default

    Hi
    It is Yetkins word for broken, meaning not connected.

    Cheers / Chris

  10. #10
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,202
    I'm Chris.

    Default

    Quote Originally Posted by agk View Post
    John Broskie the tube guy I assume. Seems to know his shizzit but I'm not liking the first tweak and can't see the point of the second.
    Hi Andrew
    Quite correct, the first suggestion is not good at all, as I have explained. The second of his suggestions is a band aid solution, and excuse for not applying star earthing in the first place.
    Yetkin has carefully read the reference material. http://sound.westhost.com/earthing.htm

    Cheers / Chris

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