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 :http://www.diyaudio.com/forums/vend...you-always-wanted-but-hard-get-they-here.html
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 .
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 :http://www.diyaudio.com/forums/vend...you-always-wanted-but-hard-get-they-here.html
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 .
Attachments
Last edited:
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..
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
naah - just a habit ; in fact - I'm not using them either , even if they are drawn
nope - I'm not a leader - I'm just not afraid of public disgrace , while posting my backofnapkinstuff
I still recall the tedious evening hour training classes of simulation software and PCB design at poly-u in '87 (including the autorouting button).
But Hey, anything less than 25 years is pretty damn modern in ZM's book.
Let's be thankfull his napkin doesn't include the lunch wipe.
Last edited:
while thinking about that servo function , puzzling is it just another of Mighty ZM's dreams , or result of lucida intervala , I realized that I really need greater voltage headroom for CCS ( Q13, Q15) , feeding tail of servo LTP . in fact - that's must in version with choke load because voltage drop across each choke section must be kept lowest possible ....... while with version with CCS load we have greater voltage loss across CCS mosfets . anyway - I think that I'll include voltage shifting in both iteration
so , after thinking about some superconducting diodes , used as voltage shifters for bases of Q11 and Q12 , also bugging my fave advisor Juma , I realized that there is always at least two ways for skinning the cat .
few diodes , where I need them , with one resistor ...... so - one tiny resistor to gnd save me of chase for superconducting diodes
so , after thinking about some superconducting diodes
, used as voltage shifters for bases of Q11 and Q12 , also bugging my fave advisor Juma , I realized that there is always at least two ways for skinning the cat .few diodes , where I need them , with one resistor ...... so - one tiny resistor to gnd save me of chase for superconducting diodes
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.