[ARC5] [Milsurplus] Low B+: The Genius of A.R.C.

[Todd, KA1KAQ]

On Thu, Oct 13, 2011 at 12:15 AM, Kludge <wh7hg.hi at gmail.com> wrote:
> -----Original Message-----
> On Behalf Of B Smith
>> Some of us are missing the point about lower voltage operation.  You
>> can look at  tube characteristics curves all day long and reach the
>> same conclusion.
>
> In any situation where theory (in this case, tube manuals) collides with the
> real world, the real world invariably wins.  In this case, these receivers
> are operating despite what the curves say, perhaps not to spec but well
> enough to be useful.

I don't know that I'd call tube manuals 'theory', Mike, but I agree
with your point. (o:  It's more a case of folks getting confused or
otherwise wrapped around the axle over what's "proper" (design) and
what will actually work (real world). In this case, both really do
work. One approach is just more sensible in the present day. As Dave
eluded to in another post about it being FUN, we're not concerned with
getting top-of-the-line, cutting edge performance out of this
equipment. We're enjoying the experience of a piece of living history
in our midst. The questions isn't whether running the equipment to
spec will give a better result(briefly, before detonation), but rather
if running it at a substantially reduced level presents a similar
experience. From Dave's results and others, it sounds like the answer
is 'close enough for our purposes' or as you say, "useful".

Not unlike the discussion of how useful tube testers are: they can
reveal problems within a tube, but excellent emission is no guarantee
the tube will perform. Have experienced this myself. Also picked up a
post war RCA SC-88 some years ago that performed well at the seller's
location (he provided a video of it in action) but was numb at mine.
It did work, but barely. Turns out he had one of those 50 gigawatt
bible thumper stations nearby. Testing the tubes showed absolutely
*no* emission from most, and only very slight deflection for a couple.
So the tester showed the deficiency, yet the receiver still performed
to some level with flat tubes. In this case, it was an easy solution,
but it remains a lesson for me on what actually will "work". Amazing,
really.

Kudos to Dave, the Mikes, and all those who actually seek out and
share solutions to the challenges of keeping this old history actively
functioning beyond paperweight mode, for us to enjoy and, hopefully,
future generations to experience.

~ Todd,  KA1KAQ/4