[ARC5] Collins xfmr ratings

[Dennis Monticelli]

I like choke input power supplies, but the critical inductance issue is a
serious one for CW usage as Ken noted.  You either have to find a high
value "swinging" choke or put up with wasting a lot of power in the form of
bleeder heat.  I would like to share a workaround.

In lieu of a high wattage bleeder, use a VR tube stack to maintain the
requisite minimum load current.  Then pick off the appropriate voltage
points for feeding the Osc and PA screens for the ARC-5.  This is what I do
in my setup so my bleeders are not power hungry and less power gets wasted.
 You only need 150mA total (not 200mA) at 500V for this scheme to power an
ARC-5.  Your keying note will improve as well.  A fringe benefit is the
attractive glow of the VR tubes.

Dennis AE6C


On Fri, Aug 15, 2014 at 9:59 AM, Kenneth G. Gordon <kgordon2006 at frontier.com
> wrote:

> On 15 Aug 2014 at 12:53, KG4KGL wrote:
>
> > Kenneth,
> >
> > I was tracking FB until the paragraph below. Are you saying the 10k
> bleeder
> > would only be consuming 25 watts, but a 50 watt resistor is used for a
> good
> > safety margin?
>
> Yes. I always figure that if a resistor is dissipating a certain amount of
> power,
> doubling its capability is "safe".
>
> But YMMV. ;-)
>
> Possibly for a wire-wound "power" resistor, that would not be necessary,
> but
> I've always been a "belt and suspenders" type anyway...
>
> Other folks here would know more about that aspect of power resistors than
> I
> would.
>
> Carl or Bruce for instance.
>
> Ken W7EKB
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