[Elecraft] K3: 630m amplifiers

Barry LaZar k3ndm at comcast.net
Mon Jul 27 21:20:57 EDT 2015


Don,
     You are making feel old. I remember the CK722. I had one as an 
audio amp behind a crystal set I built using a 1N34, not sure it was 
even an A version. I had a 210 foot piece of wire strung from the radio, 
through my bedroom window to a post in the back of our yard. I could 
hear, almost all, the AM stations in the Washington, D.C. area, all at 
once. And, that was in the 1950's. The really nice thing about the set 
up is that a D cell battery could power the thing to drive high 
impedance headphones nicely. Coupling to the CK722 was directly to the 
base with no bias. It worked. It may not have been the best design, but 
it worked. For a young kid that was all that mattered.

73,
Barry
K3NDM

On 7/27/2015 9:00 PM, Don Wilhelm wrote:
> Those first point contact transistors such as the CK722 were rather 
> 'finicky'.  Not much margin for error, and they were expensive.
> Now we can buy 2N2222As for pennies.
>
> 73,
> Don W3FPR
>
> On 7/27/2015 8:49 PM, Alan wrote:
>>
>> You could abuse a spark transmitter, but the tubes would die if you 
>> weren't gentle with them.
>>
>> Reminds me of comments I heard hams make about transistors during the 
>> tube-to-transistor transition 50 years ago.
>>
>> Alan N1AL
>>
>
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