Is there anybody built a non feedback amplifier??

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#561
lukio said:
Hello ....

I want to build a non feedback (NFB)amplifier now... Is there some body knows [...]
Click to expand...


This one is local NFB.
I really wonder if it could be improve with simply methods;
because the schematic is too simply to work proper from the start – probably there should be used precision current regulator thermally coupled with output devices?
I had many problems with regulation of the parameters during simulation.
But to whom it may concern?
Maybe anyone could give any advises (except “go to ....”)?
 

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#564
mikeks said:


Absolutely positively No.
Click to expand...

Absolutely positively YES.

My last (finished 6 month ago) and the best sounding
preamplifier project:
 

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#565
Re: Re: Is there anybody built a non feedback amplifier??

padamiecki said:

This one is local NFB.
I really wonder if it could be improve with simply methods;
because the schematic is too simply to work proper from the start – .
Click to expand...

http://www.diyaudio.com/forums/attachment.php?s=&postid=773933&stamp=1132815050

Very original idea, padamiecki.

I like it 🙂
And I think it can work good.

Of course, selection and matching of JFET and MOSFET
would be needed to make best possible results.
 
#566
😎

This one below shows good and low distortion
!without feedback!
at 60 Watt / 4 Ohm and 35 Watt / 8 Ohm

It is a Quasi Complementary Darlington power follower
Using 2 N-Channel MJL21194 for output

Is very easy to drive.
For example using a good PreAmp,OpAmp or Tube as voltage amplifier.
Input impedance is tested to > 1 MOhm


Enjoy!
Lineup DIY Audio Lab 😎
lineup
 

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#573
mikeks said:
Perhaps in theory...
Click to expand...

I wish we could have the author of that amplifier to measure it for us. Somehow, I don't believe that the practical result would be much different (if at all) from this theoretical model. Of course, you are always welcome to volunteer to build a replica and measure it for us. I'm still too busy enjoying my error correction wonder. 😀

Regards,
Milan
 
#577
Mike, I'm afraid we're getting offtopic here. I posted my preliminary measurements a while back in the EC thread.

So, folks, anyone tried that non-feedback design I linked to earlier? Looks very good on paper and in photos but I'd love to hear more about it from those who have actually built it.

Regards,
Milan
 
#579
moamps said:
Mike, I'm afraid we're getting offtopic here. I posted my preliminary measurements a while back in the EC thread.

So, folks, anyone tried that non-feedback design I linked to earlier? Looks very good on paper and in photos but I'd love to hear more about it from those who have actually built it.

Regards,
Milan
Click to expand...


moamps
I had a look at that 300B amplifier.
I am afraid I am not that good with understand tube schematics.
So I can not have the best opinion.

I see it requires plenty of transformers.
This is one drawback when building such circuits.
They are not easy to find everywhere in the world.
And not all want to or can order over internet and use shipping.

But I have no doubt that 300B not only looks good
but also sounds wonderful 🙂
And this Without Feedback 😎


Regards
lineup
 
#580
lineup said:
I see it requires plenty of transformers.
This is one drawback when building such circuits.
They are not easy to find everywhere in the world.
And not all want to or can order over internet and use shipping.

But I have no doubt that 300B not only looks good
but also sounds wonderful 🙂
And this Without Feedback 😎
Click to expand...

I agree lineup. I have some Lundhals left over from a previous build and that's one of the reasons I'm eyeballing this design as my next project. I was hoping someone would be able to share their listening impressions with us before I definitely decided to go ahead with a project like this.

Regards,
Milan
 
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