Folks:
Nearly four years ago, Don Wilhelm sent me his design for a fixed AF output
circuit for the K2. This was mainly for folks wanting to drive external audio
inputs, usually sound cards, etc.
I designed a PC board for Don, including input and output jacks, and an output
pot to control the output level.
Don had a batch of PC boards made by FAR Circuits and sold the circuit as, I
think, kits of parts.
During the past several years, Don decided that the original circuit not do the
best job of allowing for optimal placement (and mounting) of the PC board, so
he re-engineered his remaining existing PC boards to eliminate the I/O jacks,
the pot, and to lay all components flat (for a lo-profile) so he could then
install the PC board between the FP and CTRL boards, using an available 4-40
screw. Previously the board was being installed out in the 'body' of the K2
chassis, up against one side cover. You may go to
http://w3fpr.qrpradio.com/K2_Fixed_Audio_Output.htm
Info on the original circuit, PC board, and mounting
and
http://w3fpr.qrpradio.com/download_files/FP-CB%20mounting%20photos.pdf
Info on Don's current mounting method.
to see Don's writings on this circuit and the new mounting method.
Well, Don's now run out of kits and has no present plans of offer this kit
again in the near future. Of course, it figgers... as soon as he runs out
of the kits, he starts getting requests for the circuit again...
I ran off a batch of a dozen newly re-designed boards a few weeks ago. The
new boards were specifically designed to provide a low-profile installation
and to utilize Don's latest installation method (e.g. between the K2 FP and
CTRL PC boards. As it turned out, this batch had one small design flaw, I
missed grounding the GND pin of the LM386. Fortunately it was a small job of
bridging the ground pin to the nearby ground foil to solve the problem, and
all 12 boards disappeared quickly.
I have now run off another small batch (15) of PC boards if anyone is in need
of such a circuit, and if there's enough interest I'll have FAR Circuits make
a 'production' run of a batch of them for resale. SO right now, though I do
have some boards for sale ($6 ppd to US mailboxes, $7 to DX), I'm really
trying to gauge future interest, so I can decide whether to have a larger
run of PC boards made.
If you are (or might be) interested in purchasing one of the W3FPR K2 Fixed
AF Output PC boards, please drop me a note so I can get a feel for whether it
would be worth the effort to have some made commercially for resale.
I will be happy to e-mail a copy of the current PC board design and info to
anyone who is interested. These work well with PC-based CW/digital decoding
softwares.
73,
Tom Hammond N0SS
p.s.
I'll be away from the shack for a week (March 12-18) so any replies to e-mails
may have to wait until I return. But please reply NOW... you if you're like me,
you'll FORGET!
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