I was not expecting to build the F2J. It was never on my radar, but along comes a very generous member of the forum, codyt, offering a pair of very valuable SS JFETs. I figured that I would take a shot and put my hat in the ring. As it turned out I was number 34 of 34. But the story does not end there a generous benefactor, NP, stepping in and made available SS JFETs for all of us did not make the cut.
Well I’m happy to announce that a brand new DIY F2J is born. It was a little touch and go at the end, but with the help of other members of the forum, especially Ben Mah, my new pride and joy is literally making beautiful music.
codyt and Mr. Pass thank you very much.
Well I’m happy to announce that a brand new DIY F2J is born. It was a little touch and go at the end, but with the help of other members of the forum, especially Ben Mah, my new pride and joy is literally making beautiful music.
codyt and Mr. Pass thank you very much.
One other person had an issue with a Covid-related suspension of all imported goods to their country. Their package was set to return to sender, buts its stuck in limbo just like yours. Fingers crossed for you both.
Do you have information why they returned from Poland? There are no antycovid restrictions related to shipments from the USA to Poland.
And the jfets arrived 🙂 The journey took a long time, but it ended happily. I was in no rush, as I will be waiting anyway when our benefactor Mr Pass decides (I hope so) to share the J2 diagram. So I will collect further missing parts. I already have Toshiba from group purchase in the lack of a second pair of semisouths.
Many thanks to Papa Nelson and also to the Codyt.
Regards, Darek
Many thanks to Papa Nelson and also to the Codyt.
Regards, Darek

My F2J is finished and making very fine music.
I did the circuit on strip board. This is my first attempt with strip board and I am thrilled with the results.
Thank you Mr. Pass and Codyt!
I did the circuit on strip board. This is my first attempt with strip board and I am thrilled with the results.
Thank you Mr. Pass and Codyt!
Attachments
My F2J is finished and making very fine music.
I did the circuit on strip board. This is my first attempt with strip board and I am thrilled with the results.
Thank you Mr. Pass and Codyt!
Wow! That's impressive. There's a lot going on there....
And the jfets arrived 🙂 The journey took a long time, but it ended happily. I was in no rush, as I will be waiting anyway when our benefactor Mr Pass decides (I hope so) to share the J2 diagram. So I will collect further missing parts. I already have Toshiba from group purchase in the lack of a second pair of semisouths.
Many thanks to Papa Nelson and also to the Codyt.
Regards, DarekView attachment 948991
Congratulations!

Same lot code that I saw in F8 reviews.
By the way I also slowly start making J2 layout.. 😀
Too bad it probably not good for my speakers.
Wow, that is so cool Ben!! Amazing work and I have no doubt you'll really enjoy it!
Fugly!
Cheers
Fugly!
Cheers

Thanks everyone.
maximax77, the chokes are quiet. In fact the amplifier is quiet. Connected to my 102dB speakers, there is no hum or noise. I always do a CLC supply for my single ended amps.
This may become my primary summer amp as so far I like its sound, and it dissipates the least amount of heat of all my amps.
I will tweak the Vds and measure it in a few days.
maximax77, the chokes are quiet. In fact the amplifier is quiet. Connected to my 102dB speakers, there is no hum or noise. I always do a CLC supply for my single ended amps.
This may become my primary summer amp as so far I like its sound, and it dissipates the least amount of heat of all my amps.
I will tweak the Vds and measure it in a few days.
My F2J is finished and making very fine music.
I did the circuit on strip board. This is my first attempt with strip board and I am thrilled with the results.
Thank you Mr. Pass and Codyt!
Very interesting build, Ben! what are the the runcaps for? I also see two K40...
Ben, I know you do a lot of listening and building of SIT amps - how do you like the F2J compared to some of those?
My F2J is finished and making very fine music.
I did the circuit on strip board. This is my first attempt with strip board and I am thrilled with the results.
Thank you Mr. Pass and Codyt!
Fugly!

that's the spirit! everyone today is wanting nice and shiny pcbs ..... who needs damn pcbs when you can make them by your own
🙂
peppennino, the 10uF motor run caps are used as coupling caps. The input cap is bypassed with a Russian cap and the output cap bypasses the 10mF electrolytic coupling cap.
Cody, in my system the F2J sounds quite similar to my single ended 2SK180 follower amp. The distortion profile and levels are probably very similar. The single ended common source SIT amps are a bit different, with much higher distortion. The 2SK180 follower amp changed my outlook on levels of harmonic distortion. I still prefer some harmonic distortion with the second harmonic dominant, but not at the levels that I used to listen to. The F2J is keeper for me. It will be my summer amp, for use during the hottest months.
Zen Mod, yes I like the complete diy experience. The more I plan, build, test, and tweak, the more fun it is. 😀
Cody, in my system the F2J sounds quite similar to my single ended 2SK180 follower amp. The distortion profile and levels are probably very similar. The single ended common source SIT amps are a bit different, with much higher distortion. The 2SK180 follower amp changed my outlook on levels of harmonic distortion. I still prefer some harmonic distortion with the second harmonic dominant, but not at the levels that I used to listen to. The F2J is keeper for me. It will be my summer amp, for use during the hottest months.
Zen Mod, yes I like the complete diy experience. The more I plan, build, test, and tweak, the more fun it is. 😀
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