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Alfred P. Morgan One Stage
Audio Amplifier |
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This is the one stage crystal radio
amplifier from page 100 of "The Boys Second Book of Radio
and Electronics" by Alfred P. Morgan, written in 1957.
You can find a copy
here.
This is probably the simplest project in
any of the Morgan books. It only has two parts and a
battery! At least, it used to be simple, but being as
it was 60 years after the book was printed, I ran
into a bit of difficulty with the parts. |
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The parts list is
what made things difficult. See anything unfamiliar?
We need two Burgess No. 7 dry cells. What the heck is a No. 7
dry cell??
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Apparently, Burgess manufactured an AAA size
dry cell and named it the Burgess Number 7! Notice Morgan
calls the battery holder a "transistor battery" holder, so
the Number 7 battery was designed for transistor
applications. With a printer, some battery labels found
online, two AAA cells and a glue
stick, we have some Burgess Number 7 dry cells. |
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An old Radio Shack catalog confirms the No. 7
is size AAA |
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Here is the layout showing how to
mount the dry cells if you don't have a battery
holder. I made one
according to the instructions, but it didn't look right
because it
was too wide. |
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Well, it didn't look right because the
bracket in the drawing isn't an inch wide as it states in
the instructions. It's the width of two Fahnestock clips.
Look at the dimensions; 1 inch by 2 and 7/16 inches long. C'mon, man.
Can't it be two and a half inches long? Do I really need to
measure one and seven sixteenths of an inch?
It's actually one half inch by 2 inches. I had trouble bending the metal in the big clunky vise in the basement, so
I ended up with several. They were made from a scrap piece
of roof flashing.
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What about the base? It's 4 in. x 3 in. x
3/4 in. If you went to a lumber yard and asked for this you'd
have a base that is 3.5 x 2.5 x .5 inches. Let's just take
it at face value and make it exactly as Morgan said. |
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We also need three "No. 10 Fahnestock
Spring Contact Clips." Did you know they came in sizes? Me
neither. What is a Number 10 Fahnestock clip? This is right
up there with the Number 7 dry cell. After asking and
searching far and wide, guess who had some.
Mike
Peebles! He had 21 of them and GAVE them to me. |
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By far, the most difficult item to
acquire was the Raytheon CK722 transistor. They haven't been
made in over half a century. There are still some out there;
some are the most prized possessions of their owners. I've
never seen one in person. |
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You may well ask,
"How did you build the amplifier if you've never seen a CK722
transistor?" |
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