this is what I got Initially there was a super peak even with 100pf of compensation so added TPC for both upper and bottom of the vas stage it was quite controlled.
An externally hosted image should be here but it was not working when we last tested it.
You have posted on the other thread as:
I'm actually listening to the 2'nd VAS at 200w peaks now.
nearly brings tears to my eyes .... NO OEM even comes close to either
"enhanced VAS" running through a EF3.
This is what the "audio phools" pay 4 K$ for.
Next level beyond the basic concept Cordell/self examples.
Edit - just build it and and you will say WTF/WOW !
PS - I'm even amazed by the improvement beyond what can be bought.
Edit 2 - "baxandall" is the second posted VAS with the dual BCxxx's on each
rail. (you have not seen that one in Bob's book)
OS
how did u use it? what was the compensation way or how did u stabilize it?
Now that you are quoting me (I'm honored) , That is with the lower
gain ND.
Me and thimios decided on the anti-parallel for the V , the current ND
is super-pair powered.
Below are both original simulations , as they were/are being built.
If you built either , you would be VERY pleased ..... and wonder
why "hi-end" is treated as "Voodoo" ??
PS - change R32 (1K) on the "V" to get the same 27X gain as the ND.
The .txt file must be in the same directory as the simulation files.
You should get 7ppm- ND and 24ppm- V @ 20Khz. Simulations
are set to work with a single click.
OS
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Lets take the Kypton v2 in this you have just used a simple VAS ? why cant it be EF VAS? I dont think stability would be a problem. simple VAS has more distortion than EF
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The complimentary middle stage is already a beta enhancement circuit-
it also has local NFB from the first stage.
Q6 and Q8 are the beta enhancer's (like a symmetrical blameless).
Q5/7 actually locally corrects the VAS.
So , if you really look at it ... NOT a "simple VAS".
OS
V2 is only a bit faster than a "blameless" @ 80v/us.
V2 is still a "slow" (VFA). The forums "Badger" and "wolverine" are
"slow" VFA's.
A VFA can be faster . my new leach amp (spooky) is >150V/us).
The one you showed is the "old" fore-runner to the ND.
You ask what part makes it fast ? ALL of it - it's a low Z CFA.
ND swapped out that hawksford cascode for the better super-pair
cascode , speed increased by 2X (350/400Vus).
The ND also has the CFA PSRR weakness minimized , it's the
best of both worlds.
PS - you could of copy/pasted the " PULSE(-1 1 0 {t_edge} {t_edge} {1/2/f-t_edge} {1/f}) "
expression to the input generator and measured the slew rate yourself.
can that slew rates be achieved with dual N channel Jfet input?
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Ostripper can we use LSK489 in the kypton v2? I have a doubt that their gates seems connected internally with diodes.
http://www.linearsystems.com/assets/media/file/datasheets/LSK489.pdf
http://www.linearsystems.com/assets/media/file/datasheets/LSK489.pdf
Found a strange problem..
observe the square wave at the input just probed at the positive term of the pulse gen
observe the square wave at the input just probed at the positive term of the pulse gen
An externally hosted image should be here but it was not working when we last tested it.
Kypton ND V2 has got 29.86V/usec
V3 30.10
Im just measuring from 0 to 1usec if its right it has to show much higher slew rate as much as you said 200V/usec or am I measuring it wrong?
V3 30.10
Im just measuring from 0 to 1usec if its right it has to show much higher slew rate as much as you said 200V/usec or am I measuring it wrong?
An externally hosted image should be here but it was not working when we last tested it.
No , you got ME wrong.K- V2 will never do 200v !
(below 1) = BJT K-V2 with 2V square waves.
(below 2) is BJT K-ND (CFA) with the same input.
Even if you used the fancy super pair VAS on the V2 , it would not
give fast slew like the CFA K-ND.
BTW - I got 40.4v/us on the VFA K-V2 and 90V X 4 (250ns) = 360V/us on
the ND. No way around this , it is by design (topology). You measure with
2 points on the plot between the first 10% and last 10% of the rise/fall.
Edit - I don't mean that the 40V slew V2 would sound inferior by the fact
that it is 1/9th as fast as the CFA .... you only need a few V/us for audio.
OS
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