SemiSouth Donuts

[Zen Mod]

well ...... tnx to Magura and Zhou Fang , I have enough critters to play with - both 100's and 550's ;

these days I'm playin' also for first time with Eagle pcb software , and you can easily imagine my face - spinning my head - amused why I didn't start earlier

maybe I'll stop to make gadgets - just drawing pcbs is almost equally fun

so - two fresh sketches ( disclaimer - parts still have wakoo values , as result of frantic copy-paste approach in placing components in schematic editor ) - sort of concepts partially proven with Magura's LU based choke load Donut amps ;

what's different - SemiSouths instead of cascoded LUs , sort of servo (desperately needing proof of function ) and added input buffer with J310 on each input side ; buffers are cascoded and CCS loaded

these days I'll try Mini choke load SS Donut with 550's - moderate bias of 1A per side - as intended amps for my ancient 16R spks

already having experience with perky Babelfish J2 and sound which really surprised me , I have high expectations

seems that I'm hooked on this surprise of sand era , and I have impression that these critters even if somewhat on expensive side aren't so much expensive , comparing to some tubes I already have .
reasons are - they sound gorgeous , they are easy to buy here on Diya , you don't need to count working hours of them , and they don't need output xformers

I'll post these days schematics with proper values of resistors ( they're wakoo , mostly ) and - as soon I manage to make working prototypes , I'll post confirmation of that .

dunno , LU's were short lived .... I hope that these new critters will not share their destiny and that we'll have opportunity to buy them in future , for even less money than now .

but - me thinks that buying them now , either 550s or 100s or newest normally on ones is pretty clever investment ;

Magura's GB is over long time ago , but I think that Zhou Fang still have plenty of them - even newest ones - JFET SJDP120R085 are on their way
they're here :Zhou Fang's sales thread! - Parts you always wanted but hard-to-get, they are here!

smaller ones - SJEP170R550 , are good for -say- 30W of dissipation , and with that you can build any Mini already known in Papaland ;
sturdier ones - SJEP120R100 are good everywhere where IRFP150 is already bolted
well - after little more time with these , maybe I'll play a little with most weird critters - SJDP120R085
they can be put ditto in these two schmts instead of drawn '100's , tnx to CCS which is in their tail .

[spavleski]

Just Do it !

[Melon Head]

Yeah I am also interested in SJDP120R085

[Zen Mod]

edited values ;

breadboarding time ........

[carpenter]

Keep the reports coming, Choky. I know what you mean by using the software--it's almost as much fun as doing the actual building.

Love the fugly little schematics! It's hard to believe that our little Choky is growing up into the modern age of graphic art.

[vitalstates]

Originally Posted by carpenter

Keep the reports coming, Choky. I know what you mean by using the software--it's almost as much fun as doing the actual building.

Love the fugly little schematics! It's hard to believe that our little Choky is growing up into the modern age of graphic art.

I think he's only doing the hand drawn stuff for his very best friends now..

[Zen Mod]

Originally Posted by vitalstates

I think he's only doing the hand drawn stuff for his very best friends now..

it will be always like that

ZM is here to serve ..... and protect

[Vix]

Yeah, and he will advise his best friends about building tube circuits, regardless of the fact that he's currently playing with just another kind of sand

[Tea-Bag]

Papa removes the input diodes on his F1-F2J stuff.
I am not sure why your using it. But if its for not blowing the S.S. then maybe not needed.
Just a thought.
Is this Choke loaded - or Choky loaded

Edit:
Grateful that your designing with these things. Your a leader in DIY!

[Zen Mod]

Originally Posted by Tea-Bag

Papa removes the input diodes on his F1-F2J stuff.
I am not sure why your using it. But if its for not blowing the S.S. then maybe not needed.
Just a thought.
.......

naah - just a habit ; in fact - I'm not using them either , even if they are drawn

Originally Posted by Tea-Bag

......
Grateful that your designing with these things. Your a leader in DIY!

nope - I'm not a leader - I'm just not afraid of public disgrace , while posting my backofnapkinstuff