Re: Remote Power Supply Connection

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.

Patrick Turner.


> 
> >
> >Trevor Wilson
> >