Friday, October 27, 2017

k669 amp another build

 In the previous version I used 220mh chokes. I have some on hand so why not? This is not a common junk box item so I did another with some readily available 4.7mh chokes. While I was at it I made a smaller board for the build. I used this one without the output transformer. It has a reasonably good output. The one with the transformer produces an output with the AF generator control on minimum. This one requires the adjustment to be set a little off the bottom. I think I can add a transformer and it will compete with the first one. That will be another day.

I wanted to try a build that anyone could do without having to hunt the parts. This one works great with the 2SK669s and does a good job with the BSS123. I think it would work with a little tweaking with 2N7002 which is another common component.
EDIT:
I made this one with pins which are just stuck in the board. If you solder sockets to the pins heads you can simply plug in different MOSFETs and see which ones work.
You could not use chokes and it will work fairly well. The chokes do give a little boost on the output.
Use what you have and have fun experimenting!

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