Hello!
This is my first post on diyaudio and I am looking for a Pure class A amplifier with Mosfet. I have searched in slovenia, but no luck.
This amp should be about 100-140W / 8Ohm
And it has to be with mosfets!
If any of you has an schematic or PCB, could it be posted here? Please?
thx,
DJG
This is my first post on diyaudio and I am looking for a Pure class A amplifier with Mosfet. I have searched in slovenia, but no luck.
This amp should be about 100-140W / 8Ohm
And it has to be with mosfets!
If any of you has an schematic or PCB, could it be posted here? Please?
thx,
DJG
Jao kje si mona😛
Check the passlabs section of this forum..
btw,
U should use the search function for this question😀D
Check the passlabs section of this forum..
btw,
U should use the search function for this question😀D
My old 1R1 Mosfet design
For something challenging and somewhat complex, but with excellent sound quality look at the link below. It is has a fully class “A” output stage and is also a good foot warmer.
I designed this back in back in 1992 or so. My newer versions of this use a similar circuit arrangement. This project is perhaps a lot more complex than most DIY’er care for.
http://www.audioamps.com/diyprojects/poweramps/1r1/1r1.htm
John Fassotte
Alaskan Audio
For something challenging and somewhat complex, but with excellent sound quality look at the link below. It is has a fully class “A” output stage and is also a good foot warmer.
I designed this back in back in 1992 or so. My newer versions of this use a similar circuit arrangement. This project is perhaps a lot more complex than most DIY’er care for.
http://www.audioamps.com/diyprojects/poweramps/1r1/1r1.htm
John Fassotte
Alaskan Audio
Now, that is a complexed amp!
Those Aleph are really good, I shall choose eno of those - if anyone has any more schematic of A class Mosfet amplifier... Pretty please!
thx,
DJG
Those Aleph are really good, I shall choose eno of those - if anyone has any more schematic of A class Mosfet amplifier... Pretty please!
thx,
DJG
Hello!
I have a question about these Aleph's.
How do I wire the inpit signal, because there are XLR +/- and RCA U.
This might be a dummy question, but what do they mean?
I just want to give in a normal signal, over chinch connectors.
thx,
DJG
I have a question about these Aleph's.
How do I wire the inpit signal, because there are XLR +/- and RCA U.
This might be a dummy question, but what do they mean?
I just want to give in a normal signal, over chinch connectors.
thx,
DJG
DJG said:
Power - yes,
easy of use - yes
linearity - no
That's what most purists will say including the much respected Rod Elliot.
annex666 said:
What do you mean - not linear?
Aren't Mosfet's the most linear elements?!
So, RCA is that connector, which I should connect with the signal(250mV)?
What about XLR?
thx,
DJG
I will try to explain how MOSFETs work - this will give you an idea of why they are (inherently) not incredibly linear devices.
MOSFET is an acronym for Metal Oxide Semi-conductor Field Effect Transistor. (They are usually created from aluminiun and aluminiun oxide I believe)
A MOSFET relies on the field created at the gate to limit the amount of electrons that pass from source to drain - it is literally a field dependant resistor (note that it is a field created within the device). As field strength is proportional to the square of the distance from the source as the potential difference at the gate is changed in a linear fashion the field will not change with perfect linearity and therefore the device is not inherantly linear.
I hope this has cleared things up?
This is my understanding from a physics point of view, if anyone knows better why these devices are not linear I would be happy to listen to your idea.
MOSFET is an acronym for Metal Oxide Semi-conductor Field Effect Transistor. (They are usually created from aluminiun and aluminiun oxide I believe)
A MOSFET relies on the field created at the gate to limit the amount of electrons that pass from source to drain - it is literally a field dependant resistor (note that it is a field created within the device). As field strength is proportional to the square of the distance from the source as the potential difference at the gate is changed in a linear fashion the field will not change with perfect linearity and therefore the device is not inherantly linear.
I hope this has cleared things up?
This is my understanding from a physics point of view, if anyone knows better why these devices are not linear I would be happy to listen to your idea.
The inputs are designed for balanced (idealy) signals, but can be used for unbalanced signal as well.
The input stage of the amp should be a differential stage (as this is the way to reject commond mode noise on the signal line) - in this case to use your RCA connectors simply connect the signal line to the + (i.e. no-inverting input) and tie the return to the ground and - input (inverting input).
I've not seen the schematic, but this should work.
The input stage of the amp should be a differential stage (as this is the way to reject commond mode noise on the signal line) - in this case to use your RCA connectors simply connect the signal line to the + (i.e. no-inverting input) and tie the return to the ground and - input (inverting input).
I've not seen the schematic, but this should work.
...also while I'm thinking about it as this amp has a balanced input why not make a bablanced line driver to run it?
This will give much better noise rejection from unwanted signals on the cable and is quite simple - read this;
http://sound.westhost.com/project51.htm
for more information. The line driver only requires power for the op-amps and you can steal this from the power supply in your source equipment (CD player etc). Also ESP is a great source of all kinds of hifi electronics information - I highly recommend it!
Hope this helps?
This will give much better noise rejection from unwanted signals on the cable and is quite simple - read this;
http://sound.westhost.com/project51.htm
for more information. The line driver only requires power for the op-amps and you can steal this from the power supply in your source equipment (CD player etc). Also ESP is a great source of all kinds of hifi electronics information - I highly recommend it!
Hope this helps?
If a MOSFET isn't linear, a BJT is?
(I'm actually wondering, not trolling, although it initially came over that way).
(I'm actually wondering, not trolling, although it initially came over that way).
Nope. There's no linear, man, just different degrees of nonlinear.jgwinner said:
😎 Just like saying Class A amps are more linear than Class B. Just like saying that any continuous function is approximately linear if you restrict its input range enough.
Thank you, Anex666.
Your post made things clear!
You can see the schematic on the first link on this post.
thx,
DJG
Your post made things clear!
You can see the schematic on the first link on this post.
thx,
DJG
dshortt9 said:
dshortt9 the link you provided above has a very nice presentation of a good number of Aleph project diagrams.
I'm sure that all Aleph fans greatly appreciate seeing these diagrams in such nice format. The person who did this work deserves a pat on the back. Great job!
John Fassotte
Alaskan Audio
Exactly! It was as if this was leaning to 'MOSFET's don't make good amps because they aren't linear'. Then we should chuck all our amps 😀
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