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Old 14th February 2003, 04:01 PM   #11
halojoy is offline halojoy  Sweden
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Quote:
Originally posted by SumTingsBurning
>It does not utilize any global feedback, neither a Sziklai output configuration wich means that the last stage would do a lot of distortion. (It is neither class A...) If things were so easy...

Sorry, what's a Sziklai output configuration?
I gotta look that one up.
I measured the distortion on 2 different pieces of test equipment and got the same result. No it does not use global feedback.
I was trying to see how good an amp I could make without global feedback using a minimal number of parts. There is nothing unusual here, a voltage amp followed by Mosfet followers.
1 watt 0.25% FET distortion
could sound as some Tube Amps, or even better?.

And is that BAD or GOOD!?? compared with Real Hifi...

/halo
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Old 14th February 2003, 05:12 PM   #12
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Quote:
1 watt 0.25% FET distortion
could sound as some Tube Amps, or even better?.

And is that BAD or GOOD!?? compared with Real Hifi...
Yes it does sound like a tube amp. It's not the best amp in the world, only better than some.
Now if you say tube amps are not real HiFi...
I think some people in the tube amp forum might disagree with you.
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Old 14th February 2003, 06:24 PM   #13
halojoy is offline halojoy  Sweden
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Quote:
Originally posted by SumTingsBurning
Yes it does sound like a tube amp. It's not the best amp in the world, only better than some.
Now if you say tube amps are not real HiFi...
I think some people in the tube amp forum might disagree with you.
I know some disagree,
but I define hifi as low distortion.

That does not mean that hifi always gives
the best sound-experience with your ears & mind.
There are many that does not mind a certain distortion.
And certain types of distortions better than none.

for my own I prefer to know that my soundwaves are
as close to the recording as possible with todays components,
and with my wallet's capacity.

/halo - do not mind doing some teasing of tube-guys!
he still admire most of them - they know things he doesn't know
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Old 14th February 2003, 07:29 PM   #14
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Default funny you should ask...

I was looking for the same thing- just a basic A/B p-p mosfet amp. Couldn't find anything, so I decided to start working on my own. I don't know if you'd call it minimalist, but it certainly isn't that complicated!
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Old 17th February 2003, 08:57 AM   #15
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SumTingsBurning,

Sometimes I just look but don't see. At 1 W the measured distorsion is OK. I had 10 in my mind. Anyway, I would really like to hear this amp. Years ago I designed too such circuits, but then I learned too much about amplifiers and realised that such a circuit will distort just too much at higher levels. (Actually 5 W is high here...) So I never built such simple power amp. But I am always curious...Never heard any like this.

You can find a lot of information about the Sziklai output stage, just make a search for "complex emitter follower". This is a thread I started about this configuration and there is a lot of valuable information.

bt

P.S. to everyone: Please do not try to make a solid state amplifier wich has a distorsion of a tube amp. Really good amps sound just the same regardless of what kind of active elements are used. The pure reproduction of the material stored on the media has to be the aim, nothing more and nothing less.
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Old 17th February 2003, 09:33 AM   #16
halojoy is offline halojoy  Sweden
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Question Banfi T. amp - Your version of this?

Quote:
Originally posted by Banfi T.
SumTingsBurning,
Sometimes I just look but don't see. At 1 W the measured distorsion is OK. I had 10 in my mind. Anyway, I would really like to hear this amp. Years ago I designed too such circuits, but then I learned too much about amplifiers and realised that such a circuit will distort just too much at higher levels. (Actually 5 W is high here...) So I never built such simple power amp. But I am always curious...Never heard any like this.
If you decide to design or even build this type of minimalist amp,
could you please post a schematic, Banfi T..

I already got one "Banfi Amp".
I think that was a preamp.
These types of minimalistic amps is very good for
HeadPhones. With impedance 32 ohms and higher.
################################################## #############

Thanks for all schematics here!
What I find to be THE BEST MINMALISTIC AMPLIFIER
I will publish in my collection of AMP Schematics.
(Does only apply to schematics posted in this very thread)

I want to thank all the visitors at my collection.
Thank you!
.
Statistics: 3712 connections /11 days!
350/day. - A lot of downloads of schematics and PDF.
I opened the server 6th of february.

So a lot of amplifier interested people will see your Schematic
if I put it in my Server. I can help almost anyone.
Would need some more Tube amps. More of the simple-but-good-kind.

################################################## #############

/halo - The Great Webmaster
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Old 17th February 2003, 09:47 AM   #17
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Hi halojoy,

I am very busy nowadays, but I will post some of my older designs later this week, after I finished my much more ordinary power amp with MAT04s. By the way, the shematic you have is a power amp wich is working according to the simulations. (I have a working simulator now thanks to the forum )

bt
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Old 17th February 2003, 09:59 AM   #18
halojoy is offline halojoy  Sweden
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Quote:
Originally posted by Banfi T.
Hi halojoy,
I am very busy nowadays, but I will post some of my older designs later this week, after I finished my much more ordinary power amp with MAT04s. By the way, the shematic you have is a power amp wich is working according to the simulations. (I have a working simulator now thanks to the forum )
bt
Okay, a little power amp it was.
MAT04, sounds very good!

People talk about the output transistors this and that.
They have not understood that:
In an amplifier with significant negative feedback
the input/controlling stage will determine the result.
Of course all details and stages will ´have some effect.
But:
The input stage, if it is has some amplification,
will be the heart of the amplifier.
And give the "sound".

So start with a good input pair, and you have half the job done.
changing of types of output transistors, will have some minor effect.
################################################## ####################

I have often seen Nelson answer questions if guys can use
this and that IRFxxx in the output.
He just says, nine times out of ten:
Go ahead! - Yes you can! - No problems! - No worries! - It's okay!
----------------------------------------------------------------------
As Nelson is about the only raw-model I can respect
at this site, I notice what he says and does.
He is only human, sometimes I really doubt he is sane,
but many of the others, I could have or lose.
Many strange monkeys around!

/halo - monkee number 1743
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Old 17th February 2003, 12:14 PM   #19
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Default MAT 04

>
Okay, a little power amp it was.
MAT04, sounds very good!

People talk about the output transistors this and that.
They have not understood that:
In an amplifier with significant negative feedback
the input/controlling stage will determine the result.
Of course all details and stages will ´have some effect.
But:
The input stage, if it is has some amplification,
will be the heart of the amplifier.
And give the "sound".

So start with a good input pair, and you have half the job done.
changing of types of output transistors, will have some minor effect.
>

The only problem with MAT04s is their small 40v breakdown voltage, which limits your supply to +/-20v. Either you add a current mirror, or a cascode or just use them in parallel for the input pair.

In any case I have used MAT 01s on my power amp for a long time, and I think they were a remarkable upgrade from BC550s. T




Carlos
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Old 17th February 2003, 12:41 PM   #20
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"The input stage, if it is has some amplification,
will be the heart of the amplifier.
And give the "sound"."

I disagee. The input stage is just the subtractor. Even with a perfect subtraction the amp's output will not be a perfect, enlarged copy of the input. Getting the subtractor to work accurately is important but not very difficult compared to the rest of the circuit.
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