How much of the better THD with the SS Jfets is due to less degeneration (near zero) and higher transconductance resulting in more overall global feedback?
The F6 with IR parts works fine - you need to degenerate the parts with
0.47 ohms or so (maybe a little more) for thermal stability, and you will
find that there is higher harmonic distortion. Typically an IRFP240 will come
in with about twice the THD figure, but as the overall amplifier also has a
distortion contribution from the transformer, you will not see a doubling of
distortion in the overall amplifier.
The primary value of the SS Jfets are less thd and thermal drift, but you can
get along fine with other parts.
what's up , Dodos ?
except few residents , it seems somewhat silent here ......
I'm thinkin' of F6 lookalike with 2SK60 and 2SJ18 ( so having complementary pair of VFets) , using 600:1200s ( meaning 150+150:300+300) repeater .
logically ,connected as 150:300+300 , having some 3db in xformer phase splitter itself
but , that's on loooong rope , having at least 3 projects tied on same line
except few residents , it seems somewhat silent here ......
I'm thinkin' of F6 lookalike with 2SK60 and 2SJ18 ( so having complementary pair of VFets) , using 600:1200s ( meaning 150+150:300+300) repeater .
logically ,connected as 150:300+300 , having some 3db in xformer phase splitter itself
but , that's on loooong rope , having at least 3 projects tied on same line
what's up , Dodos ?
except few residents , it seems somewhat silent here ......
I'm thinkin' of F6 lookalike with 2SK60 and 2SJ18 ( so having complementary pair of VFets) , using 600:1200s ( meaning 150+150:300+300) repeater .
logically ,connected as 150:300+300 , having some 3db in xformer phase splitter itself
but , that's on loooong rope , having at least 3 projects tied on same line
I have been playing with F6 Degeneration and distortion (which goes higher when trying to maximize 2nd harmonic in my guess) and then trying to evaluate the sound to my ears. It certainly changes the sound. Darker I think.
Trying to rest more, lots of virus activity here in US and New England.
I really don't want that, after already recovering from something.
The VFET idea sounds great. I would try that if Acroman's parts would work. I've been evaluating Mike R's amp too.
On the list is matching some SemiSouthFan's parts.
Some people have been really helpful in all this - They should be mentioned.
Generg, Flochini and Buzzforb. Keeping me on middle path.
Tea-Bag needs counselors to keep his progress going when ideas become stronger than action.
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I have been playing with F6 Degeneration and distortion (which goes higher when trying to maximize 2nd harmonic in my guess) and then trying to evaluate the sound to my ears. It certainly changes the sound. Darker I think.
Trying to rest more, lots of virus activity here in US and New England.
I really don't want that, after already recovering from something.
The VFET idea sounds great. I would try that if Acroman's parts would work. I've been evaluating Mike R's amp too.
On the list is matching some SemiSouthFan's parts.
Some people have been really helpful in all this - They should be mentioned.
Generg, Flochini and Buzzforb. Keeping me on middle path.
Tea-Bag needs counselors to keep his progress going when ideas become stronger than action.
I spend (waste) 2 hours a day reading all the threads I am interested in, should be building something. I do listen to my lovely system while reading, so all s not lost.
Rush
I hope that you all will have a safe, prosperous and healthy 2013. Zen Mod. Please show a proposed schematic with focus on biasing.what's up , Dodos ?
except few residents , it seems somewhat silent here ......
I'm thinkin' of F6 lookalike with 2SK60 and 2SJ18 ( so having complementary pair of VFets) , using 600:1200s ( meaning 150+150:300+300) repeater .
logically ,connected as 150:300+300 , having some 3db in xformer phase splitter itself
but , that's on loooong rope , having at least 3 projects tied on same line
Best regards.