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Old 27th September 2009, 08:54 AM   #111
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Quote:
Originally Posted by thanh1973 View Post
Thanks Ipanema
I have modded the circuit to make a 2 gainstage J2 push pull circuit (quasi-complementary of course), and it works.
I haven't tried to optimise it yet, and I have used Irfp240 because I don't have models of the SiC JFETS yet.
I need a microscope to read your LT SPICE circuit on my laptop!!!
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Old 27th September 2009, 09:00 AM   #112
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Sorry about that.
Here is an update on it. The more I tried to optimize it the worse it got, so I have given up on it.
It works quite well with low output but once you get over 15V output it does not look to good.
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Old 27th September 2009, 02:41 PM   #113
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I'll manage to read. Do not worry
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Old 27th September 2009, 05:46 PM   #114
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The Holy Grail would most likely have very high voltage,
current and wattage ratings. It would have very low and
linear capacitance, and very high and very linear
transconductance, both with respect to Ids and Vds and
temperature (for a FET - substitute other pin designations
for tubes and such).

Complementary versions would be convenient, as well
as depletion mode self-biasing.

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Old 27th September 2009, 05:57 PM   #115
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"Sounds" like V-FETs....

Regarding the Holy Grail of amplifiers and stereo systems I have stopped looking for that. But it is always fun with new and better amplifiers.

On the philioshopical side of it, I doubt the Holy Grail comes in just two channels, but that is probably another thread in another forum in another galaxy far far away.

Also, for the time being, it seems "my" music comes in two, not five point one channels... So no need to worry about center channels or not, LFE mixing and single subwoofers and all this mess.
Vive les deux canales!

RK
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Old 27th September 2009, 06:25 PM   #116
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How about an amplifier and a speaker optimised for every musical instrument used in the music? Forget about an orchestra...just go watch it live!
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Old 27th September 2009, 06:27 PM   #117
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Holly Grail must have OPT on speaker end .....

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Old 27th September 2009, 07:29 PM   #118
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BTW are your Pumpkin named after the ugly 4.7 uFs http://www.diyaudio.com/forums/attac...amp=1191699119
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Old 27th September 2009, 07:30 PM   #119
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Quote:
Originally Posted by R-K Rønningstad View Post
"Sounds" like V-FETs....
I'm not sure we should be referring to them as V-FETs, as
this term would apply to the newer vertical JFETs but also
to our beloved vertical MOSFETs, such as the IRFP240.

In any case, I would like to see better parts yet. The
improvements we have seen lately are accidental
by-products of parts designed for better switching.

The SITs and the Sony parts are interesting for their
dependence on Vds, which allows some cancellation of
second harmonics under ideal conditions but I'm
afraid that this technique has some limitations if you
are looking for the Grail.

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Old 27th September 2009, 07:46 PM   #120
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And these accidental improvements have resulted in only n-channel devices. I would like p-channels also, but realise for some of us that is not so important.
Please correct me if I am wrong: The so-called V-FETs I am talking about, the Sonys, NECs and Yamahas from the seventies, came before the power MOSFETs as we know them, from first the Hitachi HMA-9600 and the Hafler DH-200 by Borbely a little later (both second half of the seventies). After that the power MOSFET shoved the vertical JFET (V-FET) aside and into oblivion.
Interestingly, the old V-FETs are depletion mode, while the Semi South devices are enhancement mode.
Regarding the grail, let's forget that, and have some more fun!

RK
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