The AM Forum

Has anyone built one of these?  I have the PCBs and am gathering parts. 

The construction details of T1 and T2 are a bit of a mystery, perhaps someone has built them?

Thanks

Rich

What does K7DYY say?

David Goncalves
W1EUJ

Maybe he is away, I have emailed couple times.

Rich

He will always answer. Very good about email. I hope you have a lot of patience. Those microscopic parts AND SMT devices and winding toroids was my limit. I sent my JR in for 'upgrade' and K7DYY built it..............................hi

fred

Hi Rich
I had asked Bruce the same question and below is his reply.
The LV transformer is rated at 12V 4A although
2A would do.

The gate transformer uses a BN-43-3312 binocular
core from Amidon.  The primary is 3/16" brass tubing
(from Ace Hardware) and the four secondaries are
each 1T #24 teflon.  The tubing which forms the primary
is soldered to the holes in the PCB.  The photo shows how
the secondary leads are twisted and routed.

The output transformer is two stacked BN-43-7051
binocular cores from Amidon.  The primary is 2T #16
teflon and the secondary is 4T #16 teflon.

Happy Building
Tom KC2DTQ

Thanks Tom!  Do you happen to have that photo?

Rich

Hi Rich
I believe the photo Bruce is speaking of is the one on the website.
He also sent me an updated BM. I will include both here.

Tom
 KC2DTQ

Tom,
    That picture does not show the bottom of the board.  I think couple of high quallity pictures of the bottom would be worth 1000 words.

Rich

Hi Rich

I am still collecting parts for my TX. I think photos of the completed circuit boards will be a big help since there isn't silk screening. Assembly using the schematic is a necessity.
Possibly someone who has a completed TX can snap photos for us. 

73
Tom

Hello,

Anyone have an idea what the total cost would be to build one of these?

Thanks,

Bob
wb6kwt

Are you trying to replicate the K7DYY design without buying the transmitter?

If so, I would like to suggest that the designs on the class E web site are probably easier to replicate (there are no special parts), and these designs are also much more conservative in every aspect.  The audio is also very likely to be superior (I will not comment further on this), and the RF amplifier design is much more flexible (will work into a wide range of loads).  There are also other advantages.

Depending on your ability to locate parts and do metal work, you should be able to build a 400 watt OUTPUT transmitter for a few hundred dollars ( quite a bit less if you're REALLY good with finding parts or have parts on-hand ).  I'm assuming a reasonable amount of parts hunting for tuning components, filter caps - things like that.   Boards with or without parts are available for the low level circuitry.  There is also a considerable amount of technical support available because many people have built these transmitters.

http://www.classeradio.com (http://www.classeradio.com)  for info.

Regards,

Steve

He bought the boards and docs from k7dyy Steve....

I think $50. gets you the boards, schematics, and BOM.

I think I get the gist of T1.  Two parallel stacks of toroid cores (3 each) with a brass tube through each.  Bruce includes a small pCB to join the tube at the top of the stacks.  Looped through he tube are the four secondarys (one turn) that feed the gates.

Attached picture of meager beginnings....

Rich