Re: Remote Power Supply Connection

David R Brooks wrote:
> 
> Patrick Turner wrote:
> >
> > flipper wrote:
> >> On Fri, 16 May 2008 20:40:33 +1000, "Trevor Wilson"
> >> <trevor@[EMAIL PROTECTED]
> wrote:
> >>
> >>> "Iain Churches" <IainNG@[EMAIL PROTECTED]
> wrote in message
> >>> news:yy9Xj.1624$_03.705@[EMAIL PROTECTED]
> >>>>
> >>>> "Trevor Wilson" <trevor@[EMAIL PROTECTED]
> wrote in
message
> >>>> news:694fk9F30lh2sU1@[EMAIL PROTECTED]
> >>>>> "BretLudwig" <bratzirules@[EMAIL PROTECTED]
> wrote in message
> >>>>>
news:7a2f6434985dd93af0ad7ca24683b83c@[EMAIL PROTECTED]
> >>>>>> "BretLudwig" <bratzirules@[EMAIL PROTECTED]
> wrote in message
> >>>>>>
news:6889949c0f7376f69fcc9ea26ef19be9@[EMAIL PROTECTED]
> >>>>>>> **** Brussels.
> >>>>>>>
> >>>>>>> Do it yourself and who will know?
> >>>>>>>
> >>>>>>> Put simply the use of an outboard power supply chassis is the
OPTIMUM
> >>>>>> way
> >>>>>>> to achieve the BEST possible performance.
> >>>>>> **Nonsense. Whilst an external power supply *may* have some
advantages,
> >>>>>> transferring large amounts of DC is a dumb thing to do. Using AC
is far
> >>>>>> more
> >>>>>> sensible. Capacitors need to be placed close to output devices,
not many
> >>>>>> cm away"
> >>>>>>
> >>>>>> That defeats the purpose of having the PS outboard. You want the
AC OFF
> >>>>>> the signal chassis!
> >>>>> ******elding is cheap and simple. By all means, keep the power
transformer
> >>>>> off the signal chassis, but rectifying and smoothing, THEN trying
to
> >>>>> couple the result to the signal chassis is a recipe for disaster.
> >>>> Please elaborate. What kind of "disaster" ?
> >>> **Google: 'Welder'. Welders operate on DC current. It is for this
reason
> >>> that commonly available relays have a maximum working Voltage of 27
VDC.
> >>> Much higher and the arc created can be self-sustaining. Damage can
be
> >>> considerable.
> >>>
> >>>> My own 50W amp now five years old, has been running
> >>>> several hours per day without any problems.  It meets my
> >>>> objective for a very low level of hum and noise.  To build
> >>>> the same amplifier in a single chassis with the required
> >>>> physical separation between critical components
> >>>> would have required a footprint the size of a desktop.
> >>>>>> You want the primary filter caps on the PS chassis and some more
on the
> >>>>>> signal chassis, with a choke before them that sees only the
ripple for
> >>>>>> AC.
> >>>>> **Nope. You *only* want to transfer AC between chassis. Not DC.
Unless
> >>>>> you are a fool, of course.
> >>>> The idea, Trevor, is to build an audio chassis in which the
> >>>> only AC is the signal.  It is a very good solution if it can be
> >>>> implemented in a safe way.
> >>> **Trying to use connectors for DC (with appreciable current and
Voltage) is
> >>> dumb design. Much smarter to use AC.
> >> Seems to me the 'disaster' is easily avoided by using the power
switch
> >> to turn the unit on and off instead of trying to do so by plugging
and
> >> unplugging the DC connector.
> >
> > Disasters await those who for for whatever reason tinker or tamper
> > with gear, or use it in some way that is a result of permanent
> > or tem****ary stupidity.
> >
> > Manufacturers have to ensure that nothing bad is anle to happen.
> >
> > Including say a todler poking a metal knitting needle into a hole
> > through
> > a chassis, or a finger into a hole in which the finger becomes jammed,
> > and the child struggles to remove it while contacting mains or +500V.
> > One doesn't want to main customer's child, OK.
> >
> > Disasters are easily avoided by common sense, but not everyone
> > has the same degree of common sense, so despite all the rules,
> > disasters keep happening simply because its possible that disaster is
> > possible.
> >
> > I once had a client who bought his friend's Leak monoblocs with KT66.
> > No bottom covers were fitted to the chassis. No lifting handles.
> > He tries to pick an amp up and forgets to turn it off.
> > He reaches casually around the bottom of the chassis and makes contact
> > with B+.
> > He hurls the amp with great gusto at the ceiling where a couple of
tubes
> > smash, and rain down
> > broken glass and toxic junk, then the amp does a somersault on the way
> > to the floor
> > where the remaining tibes are smashed.
> >
> > He was lucky a cup of tea and good lie down were all he needed to get
> > over the experience.
> >
> > His pocket recovered later.
> >
> The (former) Western Australia State Energy Commission put it clearly:
> the object is to protect a user who is ignorant of electrical hazards,
> but does not have suicidal tendencies.

Suicide is often unfortunate, and the result of depression,
and unfortuante if the person is a great benefit to us all when he/she
ain't depressed.

Therefore we should make it diffult to use an amplifier to commist
suicide.

Sheer determination must be employed if the suicider is to succed with
death by amp.

Padlocking a nice big tube amp around one's neck with a chain and
throwing the keys over the 
bridge rail just before following them to the water is one thing I find 
has no technical solution at this time.

Trying to listen to music while in one end of the bath with an amp full
of KT88 at the other end 
is a difficult operational condition that offers a large challenge to
the prudentious  
and efficacy minded amp designer.

Leaving a tube amp juxtapoised on top of a partially open door
and calling out to one's mother in law to 
come into the room is also another challenge for the designer if death
of someone,
or maybe more ppl is to be avoided. Recomendation:- use a bag of flour
instead.


Patrick Turner.