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-   -   10W JFET/MOSFET SE Class A, no Feed Back (http://www.diyaudio.com/forums/solid-state/90772-10w-jfet-mosfet-se-class-no-feed-back.html)

widowmaker 21st November 2006 01:52 PM

10W JFET/MOSFET SE Class A, no Feed Back
 
This is my new project:
http://bgaudio.org/images/upload/newclassaamp.jpg
1st stage - common source (2SJ103BL), 2nd - source follower (2SK170BL), power stage - common source with current source load (2SK159 & 2SJ200), no feedback, no input or output caps...

lineup 21st November 2006 01:59 PM

Nice!
 
Nice widowmaker!

Good to see you posting a project again.
They are usually very interesting, to me.
:)

your friend
lineup

widowmaker 21st November 2006 02:01 PM

10x, Lineup!
More info about this project will coming soon :)
AgTa cap is russian military production, 1000uF/6V. I think thas is better choice than Black Gate cap...

widowmaker 24th November 2006 01:25 PM

I made some changes on this project.
The schematic bocomes more simplified...
Now the servo has only opamp and few caps and resistors.
bypassing (by quality cap) the source resistor on first stage is good enough to eliminate noises from opamp...

Leolabs 25th November 2006 01:27 AM

Nice to see another minimalist MOSFET amp.:)

bikehorn 25th November 2006 06:35 AM

interesting, have you built a prototype? what kind of PS would be ideal? i have always wanted to try a capacitance multiplier.

widowmaker 25th November 2006 03:05 PM

I think that PS with CLC filters (one for each rail) is good enough.
for example:
47mF/3mH(3.5A, iron core)/47-100mF
New, modified schematic coming soon :)

bikehorn 25th November 2006 08:38 PM

i have always been interested in CLC filters but i can't ever find any Ls of the right type for a price i would remotely consider paying....what about just lots of capacitance, Krell style? or full on regulation? i have read that regulators introduce a triangular waveform into the rail while capacitance multipliers come very close to full regulation while avoiding the triangular waveform. is this true, or of consequence?

Neon_Knight 26th November 2006 12:46 PM

Another great construction from Widowmaker;)

lineup 26th November 2006 01:00 PM

2 Attachment(s)
Quote:

Originally posted by widowmaker
I think that PS with CLC filters (one for each rail) is good enough.
for example:
47mF/3mH(3.5A, iron core)/47-100mF
New, modified schematic coming soon :)


Quote:

Originally posted by bikehorn
i have always been interested in CLC filters but i can't ever find any Ls of the right type for a price i would remotely consider paying....what about just lots of capacitance, Krell style? or full on regulation? i have read that regulators introduce a triangular waveform into the rail while capacitance multipliers come very close to full regulation while avoiding the triangular waveform. is this true, or of consequence?

Attachment
Have a look at my effective C-R-C-R-C-R-C.

This time I used resistors:
0.10 - 0.22 - 0.33 Ohm
and capacitors:
4700 - 4700 - 10.000 - 10.000 uF

Result:
Very Good effective Power Supply filtering.
Almost no ripple for 2 A constant current.
In Multisim.

The drop of 1.3 Volt I can live with, because
so much easier to find some power resistors 0.10 - 0.33 Ohm
than winding your coils or try to find and buy such

----------------------------------
Have a setup of 0.10 - 0.47 Ohm (2-5 Watt) resistors at home
as well as a supply of 4.700uF / 10.000uF supply caps
.. and you will put together a nice low ripple power supply very quickly
whenever you get an idea you want to try.
---------------------------------.

lineup

See my Very Clean Supply in Attachment
here


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