Re: [IRCA] Pleasantly Plump Radios
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Re: [IRCA] Pleasantly Plump Radios



On Tue, 16 Sep 2008 17:22:46 -0400, Craig Healy wrote
> No power supply with it?  Is there a marked connector?  Usually it would
> need the filament voltage and B+.  Possibly different filament 
> voltages for different tubes.  I think that uses a UV-200 or UV201,
>  maybe with an "A" suffix.
> The 200vdc would be a small current, around 50ma max.  Filament current
> would be .250ma.  These figures come from a Google search of the brand.
> If it would run on 150v, a simple power supply could be made without 
> a transformer.  Just use a 33 ohm 1/4w resistor as a defacto fuse, a 
> diode and filter capacitor.  It *might* be able to use a D cell for 
> the filament. You'd have to do some research on the tube itself.
> All of the above could well be dangerous. (Insert usual warnings here)
> These things often ran off a 60v or 90v "B" battery and a 1.5v "A" battery.
> The 200v for a single ancient tube is rather surprising.  Many 
> places didn't even have AC power in 1923.

For starters, I certainly agree about inserting the usual warnings... On the 
left side are two posts: "A" (antenna?) and "G" (ground?). On the right side 
are four: Top is marked "B+" and second is left blank although "Output" 
appears in between. Bottom two are "B-" on one side and "A+" on the other, 
the very bottom post is marked "A-".

Inside is a Crossley Cincinnati Type "D" Condensor and appears as two plates 
that move closer or further part as you tune the front dial. There is also 
what appears to be a resistor and is labeled "Electrad Three". It looks 
somewhat like a modern day resistor except that it is 1 1/2 inches in length 
and about 1/4 inch in diameter. Next are two circular plates made of wound 
wire, the larger of the two is in a fixed position, while the smaller can 
move in and out, approximately 1" away when fully pushed in and about 1/8" 
when fully pulled out. Last piece is circular and appears to be variable 
resistor. If you've ever looked inside a basic antenna tuner (RLC circuit), 
it vaguely reminds me of one.

Last is the one tube, a Cunningham CX300-A with four posts at the bottom, 
and a very short stub sticking out the back preventing improper placement in 
it's socket. (Was 'idiot proof' a phrase from the 1920's???) The "A" and "G" 
posts connect by short wires to the condensor. The "B+" post does not 
connect to anything inside the radio, so I think it must be used to power 
the headphones.

I'm sure I'm missing some of the important details, I'll see what kind of 
luck I have trying to take some pictures of it. I acquired this from a 
friend, and he thinks the there was at one time an article in Montoring 
Times about this model.

That's it for now.

Joe

-- 73 de Joe Miller, KJ8O, Troy, MI -- Grid EN82 --
------ WOW! Homepage (http://www.wowway.com) ------

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