Nelson Pass Mosfet Tester in action.
Started testing P channel devices.
An externally hosted image should be here but it was not working when we last tested it.
Started testing P channel devices.
Nelson Pass Mosfet Tester in action.
Really exciting Pico....nice pcboard! Nice to get a glimpse into what your world looks like.
You have my attention!
Started testing P channel devices.
Yeah, a CNC pcb milling machine.
Yes they match amazingly well considering they were the first 4 I measured.
Basic schematic. I'll add all values later.
Feeling somewhat disappointed (Nelson's time machine at work again, hahaha) that this is now basically a less fearless version of F7 (more fearless than F5 though), probably no interest in this, other than it has very similar specs to F7/F5 (obtained with negative feedback) and will be much easier to successfully build than the F7 for the DIYer dumb dumb (touch wood).
Feeling somewhat disappointed (Nelson's time machine at work again, hahaha) that this is now basically a less fearless version of F7 (more fearless than F5 though), probably no interest in this, other than it has very similar specs to F7/F5 (obtained with negative feedback) and will be much easier to successfully build than the F7 for the DIYer dumb dumb (touch wood).
Attachments
Last edited:
Yes, but without all the other bits, much dumber (I prefer dumber ).
No source resistors, no thermistors, no current limiting circuitry, and has dominant 2nd Harmonic which F5 didn't have.
I suspect it should be a hybrid sound of F6 and F5, so should be quite pleasing to listen to.
Edit: Many years ago I also built something similar with 3 pairs of IRFP240/9240. That one had source resistors (this one doesn't ). It sounded great but the bias stability scared me a bit. This one is rock solid and meets all my requirements more so than F5.
Last edited:
well , good try in Dodossnesss , but you'll never reach sky high levels of same , which Uber Dodo is well known for
(reinventing Da Wheel , name of the game)
however , that just means you didn't do your homework - several Greedy Boyz already made that - F5 with laterals and no current limiters
besides - laterals having negative TempCo above 100mA , there is no need for NTC ....... maybe adequate PTC , if you're splitting da hair type
first one doing that , from memory, was Jackinnj (moi always having trouble to remember exact spelling) ; he's even still selling 2SJ201 and cousin in his small store
whatever - that's good amp ; but , I would (in your boots) put that Zen Amount Pot in parallel to input JFet source resistors , as Papa made in second revision of F5
Last edited:
well , good try in Dodossnesss , but you'll never reach sky high levels of same , which Uber Dodo is well known for
(reinventing Da Wheel , name of the game)
however , that just means you didn't do your homework - several Greedy Boyz already made that - F5 with laterals and no current limiters
besides - laterals having negative TempCo above 100mA , there is no need for NTC ....... maybe adequate PTC , if you're splitting da hair type
first one , from memory, was Jackinnj (moi always having trouble to remember exact spelling) ; he's even still selling 2SJ201 and cousin in his small store
whatever - that's good amp ; but , I would (in your boots) put that Zen Amount Pot in parallel to input JFet source resistors , as Papa made in second revision of F5
Well you didn't do you homework (hehehe)
, I was the one who originally suggested/observed changing source resistance of jfets in F5 would alter harmonic profile, brainy Papa came along and suggested putting a pot on it.Anyway to give the full background behind this amp design, in July 2009 I wanted to build a simplified F5 with a bit more grunt, the picture below was the start of that building process (done point to point). I was very happy with the sound of that amp (back in 2009) but the bias seemed to keep drifting upwards, which was a little worrying at the time.
The amp had 3 pairs or IRFP240/9240, no thermistors, no current limiting but had source resistors.
This amp preceeded every other modified F5 (that I am aware of) including F5 turbo and Juma's F5 with 2sk2013/2sj.
This was the start of what I built back then, a few people said it wouldn't work (they were wrong, hahaha)
I don't mind if this Lateral version has already been built, it was my idea to do it 6 years ago, I never proceeded at the time cause Juma said he had built one and didn't think it was better, but he didn't explain exactly what he built.
I don't really like cloning stuff verbatim, I like pinching ideas and adding my own. I build for my own design requirements that's it.
99% of everything is plagiarised you'd think that would teach us humility, but it doesn't.
My feeling about this is, there is nothing new under the sun, so we may as well just embrace it.
I have some other amp ideas which I've never seen done before, which I will get around to doing but I'm bloody slow at getting these things completed.
Even if you do something original, people always come along and want to knock your sand castle down to try and make their's look better. You can't win either way.
Anyway it's been a very long time coming for me to complete this amp so I'm very happy to have finally built this one (an even more simpler version than my first one).
Attachments
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.