Re: Remote Power Supply Connection

On May 21, 12:20=A0pm, Patrick Turner <i...@[EMAIL PROTECTED]
> wrote:

> > No connector should be "solid" at any end in this sort of
> > applications. Both ends should be suitably socketed against the sort
> > of eventuality you describe. Mil.Spec. connectors and some medical
> > connectors, machine-tool connectors and others are locking-types for
> > very good reasons - the consequences of a fall such as you describe
> > may be far less than an accidental unplugging - but that sort of
> > equipment has suitable strain-relief designs as well.
>
> There are not many plug and socket designs which can withstand sideways
> forces of say 20 times the weight of an amp or PSU due to one or the
> other
> falling off a bench and being halted in the fall by a cable.
> So the umbilicals MUST be longer than 1.2 metres, so that if an amp
> chassis and psu
> are both on a table or bench of say 750mm height then
> a fall to the floor by either chassis doesn't wreck a cable or the
> connector.

That is the point. And a fall is not the only potential for forcible,
sudden plug removal. There are tripping persons, running dogs (pun
intended), even small children who might get involved if
unsupervised.

> 1.5M is a nice length, and if too long one loop tied up with
> a loop of masking tape won't hurt.

No, it won't and I agree, a good length.
> But remote PSU should be REMOTE, so on the floor they go!
>
> The turn on switch should be on the amp chassis and turn on
> is achieved by the switch grounding one end of a relay coil requiring
> 12Vdc.
> In the psu chassis the live end of the relay coil is connected to a 5VA
> 12Vdc auxiliary dc supply.
> This supply also sends 12Vdc to the amp chassis to operate active
> protection measures.
>
> So there is NO access needed for the psu, and with its silicon diodes
> its just like a gigantic plug pack, outa sight and outa mind.
> No need to worry about it.
>
> > I would posit the umbilical should be male at the P/S, female at the
> > Amp.

> Huh?, I always have a female chassis socket at th psu, and the cable is
> hard wired into the
> amp and has one male plug. Is that what you meant?

Nossir. My *preference* would be that neither the amp nor the PSU are
hard-wired, but the umbilical is a separate entity plugged at both
ends with appropriate opposite receptacles at each box.

> =A0The strain-relief to the (presumably armored) cable should be
>
> > sufficient to carry the weight of either end, but, again, the
> > connector should come apart well before umbilical failure. And given a
> > proper design along the lines Patrick has described, DC voltages would
> > either drop within a few millesconds, or be entirely disconnected. The
> > days of the old Dynaco/Eico octal plugs at either end of the umbilical
> > to octal sockets at either component is simply nuts any more - 'cept
> > for Bret, of course.
>
> I think octal plugs and octal valve sockets are fine.

And you take the appropriate measures to make sure that this is so.
Writing only for myself, and these days, I would not use them were I
in that position. And this for TWO (2) reasons: 1. Better means are
available that handle all the heroics, ****elds and set-backs as part
of the design.  2. I have not, will never, make a custom amp for
another person. Accordingly, expense is no object when I do things of
this nature, so spending $100 - $150 or so on the appropriate
connectors with strain-relief and freeloading from any of several
sources I have the appropriate Armor-Flex cable would be my choice.
Crane cables are excellent, especially the sort with the steel mesh
below the first layer of rubber insulation. They can get a bit fat,
but not really a big deal.

And we have all three potential threats in this household on a regular
basis -large, active dogs, sometimes clumsy people and small, very
curious, very active children. Hence my "placement" of tube equipment
in this house even if  covered - high and out of reach.

> Very convenient actually.
> If they are yanked straight, iti's good that they pull out easy.
>
> I use an old tube base, solder up all the wires well, and drill out the
> spigot
> and place a 4mm threaded rod inside projecting back up where the wires
> are.
> This re-inforces the spigot which can often get broken off when someone
> treads on plug.
> 120Kg audiophiles are like big dopey elephants sometimes.
> I sometimes cut off the bakelight or plastic surround down to the botton
> of the base level.
> Then I get some PVC conduit and cut a 30mm length which fits snugly
> around the
> plug with its soldered wires. One ends up with a very rugged plug
> costing almost nothing,
> and one that can be easily replaced by cutting a damaged one off and
> placing a new made one on.
> Finally, I pour it some polyester resin to fill the plug to stop wire
> movement
> and bind it all together.
>
> Its possible to also glue a second PVC tube over the final plug so this
> tube projects
> slightly further than the location spigot, tand thus it shrouds the
> pins.
> But I have never bothered because octal sockets made to allow a shroud
> to push in
> are not made afaik, and are too hard to diy.
> I have 20mm plywood blocks around the octal sockets with a neat sliding
> fit for the
> plug. This prevents side ways foces on the cable from yanking the plug
> over
> and bending pins.
>
> The beauty of the octal plug ans socket is that it IS designed for tube
> amp voltages and currents

And heat. Don't forget the heat on those bases.

> In one other amp I have here I have ONE psu chassis for two power amp
> channels
> which are on one chassis. I have three octal plugs and sockets and 3
> mobile crane wire
> cables twisted and bound together; extremely rugged cabling.
> This set up was the first lot I did, and is for my own use only.
> I have never had any troubles.
>
> Come back in 200 years and the cables will be fine.

Very most likely. Just not in this house - for now, for the reasons
stated.

Peter Wieck
Melrose Park, PA