Conference cookie::notes$archive:cd_v1

    Happens on the D-7 too.
    
    (the power leakage, that is)
    

I found with my D-7 that the leakage was from the receiver.  I had the plug for
the receiver backwards and that was leaking from the input to the receiver to
the output from the D-7.

Dan

    Mine does it with the headphones plugged in.  Does my brain generate
    12 volts? :-)
    	
    Anyone here measured the in-line resistance of the leakage current?
    

    What is in that idiotic power pack?  An AUTOtransformer?  This is
    rather ridiculous!  Reversing the plug indeed...no side of the power
    line should have any measurable conductance to anything a user can
    touch!  That is the purpose of the external power supply, for heaven
    sake!
    <Flame off>
    
    Has anyone bitched to Sony about this?  I think I may do so.  Any
    suggestions on where/how?
    
    Burns

    We had a seminar on electrical safety here in NRO awhile back by a guy
    from OSHA (he has appeared on Good Morning America too) on the subject
    of the correct way to plug in appliances.  Because of the polarity of
    AC outlets, if an appliance is plugged in incorrectly, there exists an
    electric field (the thing is still live) even though the switch is off.
    In other words, don't grab an old metal electric coffee pot and stick
    your hand in the sink, or you'll get zapped for sure. 
    
    This may also be the cause of the humming experienced in the CD player.
    There is a slow movement to ensure that electrical appliances go into
    the wall socket only one way, but the appliances that have them are
    limited, and the manufacturers really don't seem to want to get
    involved. 

    In audio equipment, the leakage current is usually quite low. Before
    anybody gets TOO bent out of shape about this, remember that they
    still make TV sets with one side of the AC line connected to the
    chassis.... but with their polarized plug connected to a
    correctly-wired outlet the chassis is connected to neutral.
    
    Audio equipment is usually ungrounded to help avoid ground loops;
    however, it's probably a good idea to have a single point in the
    system grounded to the power-system ground for safety.  When I ground
    my tangled mass of audio equipment (turntable, preamp, power amp,
    2 CD players, tuner, and equalizer) the total leakage still won't trip
    a (recently verified) Ground-fault interrupter.  Just for hahas
    I'll try and measure it this weekend.
    
    Quote from the Crown PL3 manual: "NOTE: Crown assumes no liability
    whatsoever for operation of ungrounded auxiliary equipment, nor
    for the violation of UL or electrical codes."  They tell you this
    right after they explain why they don't have a 3-wire cord on the
    unit.
    
    						...tek

    re .6:  TVs with chassis connected to neutral:  Yes, but the chassis
    is not supposed to be touchable.  I bet that they volume control
    pots are not mounted on the chassis to keep the shafts from being
    connected on one side of the line.  And remember that neutral is
    not the same as ground if there is any current flowing through it.
    
    re Ungrounded audio equipment:  I agree there too...the problem
    is that the CD is NOT ungrounded.  It has an unpolarized plug, and
    it has some conductivity between the line and some metal that I
    can touch.  I have not noticed any audio hum...just that tingly
    feeling that you feel when you touch something which has leakage.
    I am afraid that I will get hum, though, when I connect it to my
    amp for just the ground-loop reason that you mentioned.  I am also
    concerned about the possibility of AC appearing on the audio line
    and zapping something.  I plan to measure the leakage before I connect
    it to anything.  I will report back when I do.  (I just found my
    DMM in a box in the basement after moving!)
    
    Burns
    

    Hmmm... maybe we're using the term 'grounded' to describe two different
    things... by 'grounded' I mean a metallic connection between 'system
    ground' and the third prong in the outlet (or the center screw or
    whatever).  If you have 13 volts from case to the third prong, then
    either the case of the player isn't connected to the shields on
    the audio cables, or the whole system isn't connected to ground.
    I'd be a little suprised (tho not amazed) if the player case wasn't
    grounded... much less surprised to find the whole system floating.
    If you don't test your household circuit breaker by blowing up your
    ammeter shunt when you check the leakage, check to see if the voltage
    exists between case and signal ground... If the signal ground is
    bouncing at 13VAC, ground the whole system.

    Problem is, the D-5 does not have a third prong.  It has a power
    supply with a two-prong plug built in, and a wire leading of to
    the D-5 which should be carrying 9VDC completely isolated from the
    AC line.
    
    BTW, I uncrated by receiver (Sony STR-2045) and tried plugging the
    D-5 into the AUX input port.  All worked fine...no hum, no zap.
    Despite my earlier statement, I still have not done the measurement.
    
    Maybe I am making a big storm out of nothing.
    
    Burns

    Re .9:
       Maybe you are.  I run my D-5 into my receiver all the time (in
    fact, I have yet to use it as a portable), and I never have hum
    problems.  
    				Steve

    I am supprised that no one has mentioned the source of most ac
    leakage in audio equipment.....RFI filter caps.  A lot of manufacturers
    place a cap between hot and ground where the line cord comes into
    the chassis.  This is to eliminate higher frequency interference
    from getting into the equipment from the line.  Depending on the
    value of the cap, you can get enough current flowing at 60hz to
    cause the type of voltages being quoted.  Multiple outlet strips
    and protection circuits will also cause this problem.  It really
    is not a problem as long as you don't have any hum in your system,
    if you do, you might try taking these caps out!
    
    Dennis
    

    ARGGH!!  If you remove them, don't blame me or the other amateur
    radio operators in the neighborhood if your system starts picking
    up signals not intended for it!  I have been going around putting
    filters INTO equipment all over the neighborhood where the manufacturer
    was too cheap to supply it, to keep my neighbors off  my back. 
    At most, replace the caps you don't like with better ones.
    
    Charlotte (KQ1F)