Re: Remote Power Supply Connection

On Sat, 17 May 2008 06:22:59 GMT, Patrick Turner
<info@[EMAIL PROTECTED]
> wrote:

>
>
>flipper wrote:
>> 
>> On Fri, 16 May 2008 12:22:33 GMT, Patrick Turner
>> <info@[EMAIL PROTECTED]
> 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.
>> 
>> Ok, You convinced me you shouldn't be using HVDC umbilicals.
>
>I don't think I have done that.

Clearly your purpose or else there would have been no need for your
'safety' lecture.

>
>Umbilicals with HV over 1,000V are rather more dangerous than with V
>under 700V.
>
>However, with peak voltages under 700V a well made umbilical its self
>isn't the slightest
>bit more dangeous than a lamp cable, heater cable, or any of the 
>2 dozen other mains cables littering evryone's houses these days.
>
>The main problem is what happens if someone pulls out the plug end of an
>umbilical 
>from a power amp and grabs all the pins with a hand within say 0.5
>seconds.
>
>Hence the need to have some sort of delay built in so that 
>a retaining screw is needed to be turned right in to activate the turn
>on 
>relay, and when partially turned out the amp turns off if it already
>turned on.
>
>Reverse dides are just fine, and I have them for main B+ and B- rails.
>
>But other biased heater windings still present a danger and the diodes
>cannot be fitted.
>
>Take care and design and build well fellas.
>Care is the ultimate insurance premium.
>
>Patrick Turner.
>
>
>s  xtphablebale
>> 
>> >
>> >Patrick Turner.
>> >
>> >
>> >>
>> >> >
>> >> >Trevor Wilson
>> >> >