wow nice!!! Jama your schematic looks like its missing something around the input buffer (Q4,Q5 DC path to earth)? Or maybe its just me who'se missing something))
Hi kasey - chalk that one up to me as the scribe. The buffer earth path is "implied" and left off as it was getting crowded in there. It is needed and should be there. My bad.
I have a question for all. With one tokin alone, I found that frequency response is a lot better with one THF51 than one 2SK180. I have not graphics, but I measured it. With thf51 I found that is flat until, more or less 70 or 80 Khz, and with 2sk180 (one of mounted) this response is a lot worse, flat until 25 or 30 khz. Well.
Now I mount two 2sk180 in parallel. Frequency response is a lot better. Look square wave at 10Khz and (really 6.8/2 ohm).
I am using 50ohm output of generator all time.
Now I mount two 2sk180 in parallel. Frequency response is a lot better. Look square wave at 10Khz and (really 6.8/2 ohm).
I am using 50ohm output of generator all time.
Big thanks Jama for amazing work and schematics. Always fantastic sit's topology explorations.
Audio input transformer option are interesting or 2SK79 ?
Have a nice day
Hi Christophe. How are you?. Use of 2sk79 it is not necessary. You can use what you like.
For full output, always in function of transconductance of vfet pairs, you need a little of voltage gain at input, and sure the buffer.
I simulate for buffer position 2sk79 as cathode follower and 2sk170 and 2sj74. The best results were with the last, being transparent in simulation. And 2sk79 introduce a lot of harmonics.
Other possibility is use the fantastic jboz pre with one 2sk170. I used when I tried csx1 and I liked a lot.
But these ideas are only subjetives.
Best
For full output, always in function of transconductance of vfet pairs, you need a little of voltage gain at input, and sure the buffer.
I simulate for buffer position 2sk79 as cathode follower and 2sk170 and 2sj74. The best results were with the last, being transparent in simulation. And 2sk79 introduce a lot of harmonics.
Other possibility is use the fantastic jboz pre with one 2sk170. I used when I tried csx1 and I liked a lot.
But these ideas are only subjetives.
Best
For reference, with this ixys mosfet and using one nice power pot of 10ohm 100w, i could get values for current of ccs, so
3.1 ohm -> 0.45 A -> 1.39V
1.25 ohm -> 1.09 A -> 1.37V
0.85 ohm -> 1.58 A -> 1.35V
0.56 ohm -> 2.34 A -> 1.32V
and .22//1 ohm -> 6A -> 1.08V
3.1 ohm -> 0.45 A -> 1.39V
1.25 ohm -> 1.09 A -> 1.37V
0.85 ohm -> 1.58 A -> 1.35V
0.56 ohm -> 2.34 A -> 1.32V
and .22//1 ohm -> 6A -> 1.08V
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Thanks Juan Antonio i am fine after i see your diy work i guess you are fine too
Yes i agree if simple jfet buffer give you satisfaction keep it !
Some very apreciated by audiophiles 300B SET's amplifiers have pentode tubes drivers some others are all triodes
i was curious if new all vfet's signal path are possible today.
Remember Papa speak with passion and entusiasm about Yamaha B-1:
https://www.youtube.com/watch?v=cyfdm4zsPx0
My hats off for Dady great amigo
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