Re: Remote Power Supply Connection

Trevor Wilson 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]
> >>>> Fuck 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!
> >>
> >> **Shielding 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.

Well now, you'd really know wouldn't you, after you've 
designed and built so many amplifiers.

An octal socket has no trouble with DC, and its DC that 
is conducted effortlessly from circuit to vacuum tubes
via the pins. 

As long as the direct current is low as it usually always is with 
B+ and B- supplies, the octal is fine for up to 1,000V.
the typical current rating for a single octal pin and its gripper 
is 5 amps, about right because a KT88 needs 1.8A of heater current.
But with an anode supply, say with +500V, even with 12 x KT88
used with each drawing 60mA, there is only 720mA total.
Where I have above 500Vdc on a pin, I leave the two pins each side 
disconnected to anything, or use the adjacent pins for 
other B+ voltages so a huge potential difference doesn't exist.

In my 845 amps, there is 14Vac transfered to the amp chassis where there
is a rectifier 
and choke input. Peak charge currents are low, and the 3.4A of 845
heating current 
does not over stress the octal pins.

In one amp I have 3 octal sockets for the umbilical cables
with 4 and 5 way mobile crane cabling. 
Pins are tied together to get extra rating for heater current to 12
output tubes tubes 
used in two channels.

There are very few plugs and sockets other than octals if any that are
as cheap, simple,
require no special crimp tools, have good voltage insulation ratings,
good current ratings for 
tube amps, and which can be easily be beefed up abd ruggedized and
fitted with screw clamps
and pressure switches if need be.

If you are so darn wise and experienced,
please tell us EXACTLY how YOU would do the umbilical and amp design.

But I think you have not the slightest idea that's any good.

Patrick Turner.  
> 
> Trevor Wilson