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Alfred P. Morgan One Stage
Audio Amplifier |
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It's a FAKE!
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It's a real Germanium transistor, but not a CK722. I made it out of a piece
of wood and ten coats of spray paint.
The transistor is a TUNGSRAM AC125,
bought on ebay from a guy in Bulgaria. |
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Here's the wooden stick I used. The original
plan was to mold a
CK722 transistor out of epoxy. I stuck the carved stick into a lump of
home made clay,
dropped in a transistor and filled it with J. B. Weld. When
that didn't work I tried modeling clay and epoxy. After several failed attempts I gave up, cut the end
of the stick off and drilled a hole in it. |
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It ALMOST worked!
Here are the AC125 transistors in the epoxy. Dang, so near and yet
so far. |
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These are real ones.
I based my fake one on these pictures.
Mine looks a bit clunky and I suspect the real ones are smaller.
According to legendary small set designer Mike Peebles, "Just
about any Germanium PNP Transistor will work in place of a
CK-722. Most will likely work better..." |
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When the book was printed in 1957, a CK722
was $2.20. That's more than $20 today. What kid reading this
book had $20 for a single transistor?? Ironically, today you
can buy 50 transistors for $2.20, but an actual CK722 will
set you back $50.
So how much would a modern transistor cost in 1957? $2.20 in
the year 2020 would be worth 24¢
in 1957. 50 transistors for 24¢
is about 4 for a penny. |
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So what is this and what does it do? It's
an audio amplifier for a crystal radio. It doesn't make the radio
work any better but it makes it much louder, which gives the illusion the radio works better. |
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There is no on/off switch. Connecting the
headphones completes the circuit. The volume is VERY loud on
a strong station. You probably need three volts with a real
CK722 but I think a single dry cell would work fine with a
modern transistor. As a matter of fact, I was listening to
the radio while taking these pictures because I could hear
the headphones on the table. |
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A Raytheon CK722 was actually a
repackaged CK718 that didn't meet specifications. They were
also relatively expensive. The transistor used here cost $0.29 in 2017. Actually, they were 10 for
$2.90, imported from Germany via ebay. I thought that was
appropriate since they are Germanium transistors.
When I made a fake CK722 it wasn't much different than what
Raytheon did, and it probably works a lot better.
Morgan states in his book that over 10 million transistors
were manufactured in 1956. A typical, run-of-the-mill Quad
core i7 microprocessor contains 731 million transistors. Using 1956 technology, it would
take 73 years to make the transistors for ONE core i7
microprocessor. |
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Here's the schematic. Morgan said to connect
the amplifier to the radio through a capacitor, so the
capacitor was built onboard the amplifier. It didn't work!
The sound was very distorted, so it was removed.
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A crystal set, the
Morgan amplifier and a pair of Superex "Sensiphone"
Featherweight made-in-USA "quality" headphones. (That's what
it says on the box.) I was able to remove the ground wire
and still pick up stations with plenty of volume.
In this
case, the coupling capacitor WAS needed. I guess Morgan
didn't include it on the chassis because the need for it
varies among different crystal radios. |
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Morgan's radio books were written so you
had to read them and think about what you are seeing, For
instance, in one rendering the positive wire is on the left
and in the other it is on the right. Which is correct? You
have to look at the schematic, then you learned the schematic symbol for a battery and a
resistor and a transistor. Also notice on the left are two
1.5 volt cells, but on the right is a 3 volt battery. More
than one cell is a battery. |
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