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Negative feedback - right or wrong to use?
Negative feedback - right or wrong to use?
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Old 6th February 2018, 05:13 PM   #51
Davey is offline Davey  United States
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Quote:
Originally Posted by Mikelandjelo View Post
I am finishing my current development about this....I achieved pure linear response without any negative feedback.Output power is 200W and i am finalizing this with 2x2000W amplifier design which i will make in next month or two.If i dont sell the design (project) i will offer to sell it to public and i will show a demo video of it.No matter whats written till now that doesnt mean that things cant be improved further.
You've got negative feedback in there somewhere. I guarantee it.

Dave.
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Old 6th February 2018, 06:08 PM   #52
Mikelandjelo is offline Mikelandjelo  Serbia
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Davey can you put 100 000USD on that what you are sure about?....i will do same from my side.Who is right will take all.I know exactly what i said and whats the weight of my words and that what i said about my design is exactly what i did and how its done.Absolutely zero feedback is what i made and my amplifier doesnt work as power supply....as all amplifiers are made here.Sound is VERY different from anything i made and heard in past....in positive meaning of course + on clipping there is no clicking and sharp noise but exact same thing as in AB class.....soft distorsion.Also i made automatic DC offset canceling and my design is working on single supply.

Last edited by Mikelandjelo; 6th February 2018 at 06:12 PM.
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Old 6th February 2018, 06:25 PM   #53
DF96 is offline DF96  England
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There is, of course, one easy way to design an amp which doesn't use feedback:
1. first, design an amp which uses lots of local feedback
2. then carefully note each type of local feedback (followers, degeneration etc.) and redefine each of these to be 'not feedback'
Job done!
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Old 6th February 2018, 07:05 PM   #54
lcsaszar is offline lcsaszar  Hungary
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Quote:
Originally Posted by Mikelandjelo View Post
Davey can you put 100 000USD on that what you are sure about?....i will do same from my side.Who is right will take all.I know exactly what i said and whats the weight of my words and that what i said about my design is exactly what i did and how its done.Absolutely zero feedback is what i made and my amplifier doesnt work as power supply....as all amplifiers are made here.Sound is VERY different from anything i made and heard in past....in positive meaning of course + on clipping there is no clicking and sharp noise but exact same thing as in AB class.....soft distorsion.Also i made automatic DC offset canceling and my design is working on single supply.
Hi Mikelandjelo (correctly: Michelangelo), all regulators use some form of negative feedback. An audio amplifier is a voltage regulator, that regulates the amount of the supply voltage appearing at the output according to the input signal voltage. Otherwise imagine that you change the supply voltage by +/-10%. Will the output voltage change also by +/-10%? It will not, because of regulation. Some call it PSRR, it is negative feedback.
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Old 6th February 2018, 09:25 PM   #55
Mikelandjelo is offline Mikelandjelo  Serbia
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I said what i had to say and i described what i made....PSSR can be solved other way.
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Old 10th February 2018, 11:09 AM   #56
AllenB is online now AllenB  Australia
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Has anyone addressed whether it should be the responsibility of an amp to properly handle a complex load. I can't see that it should and I don't expect mine to do that.
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Old 10th February 2018, 04:18 PM   #57
PRR is offline PRR  United States
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Originally Posted by AllenB View Post
Has anyone addressed whether it should be the responsibility of an amp to properly handle a complex load. I can't see that it should and I don't expect mine to do that.
Most users would not know a "complex load" if it urinated on their carpet.

It is the commercial designer's job to make an amp work good for 99+% of all buyers.

It isn't that hard if Product Functionality and Sustainable Business is part of the design brief. OTOH if the job is to pack maximum buzzwords into the lowest price (or highest profit), and the designer gets paid-off before the files go to production.....

If a load has "some" series resistance, it is not that hard to design for huge chunks of reactance hanging off of that. If the producer is reluctant to add $4 more power devices, $0.40 of BJTs+LEDs can implement shutdowns and error flags to save the amp and inform the user and support staff why the amp is unhappy (rather than dead).

OK, we can't cover "all" user conditions. If I rig my GAZ-5000 to modulate a 10KW AM transmitter, and omit all RF bypass "for extended highs", there's gonna be sparks.
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Old 10th February 2018, 10:44 PM   #58
AllenB is online now AllenB  Australia
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Whoever decided that amps should cover the speakers, we should say thank you. Everyone would have cottoned on that it reduces linear distortion and most would be happy. But it's not the natural order of things. I notice speaker manufacturers sat back and said nothing.
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Old 11th February 2018, 01:26 PM   #59
Mikelandjelo is offline Mikelandjelo  Serbia
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When i am talking or singing i am amplifier of my voice produced in my throat and i am the source.Will my brain correct anything from what is received in my ears to make me to sound ALWAYS exactly THE SAME in any enviroment?This is how nature works and WE engineers decided that we know better than nature.Amplifier and sound thats comming from speakers is PERSONAL THING FOR EVERY HUMAN ...... making it to "look right" for a machine (osciloscopes and spectrum analyzers) makes that universal and forced thing....It will always sound THE SAME for 99% of us (wow this is best sound ever ..... whoa)......

I am doing engineering for last 20 years ..... not like a robot but as a being with thought through emotion that i will receive from every result that i achieved.And this coused me to REthink the philosophy of amplification and to start building MY PERSONAL amplifier and not some amplifier that measures great.So i built amp that i feel is good......after more than 15 years.You can bet that this is not about the money.

I am very sharp in engineering and i am making for living from that.....But things are mostly presented to us and we always accepted them as they are presented.Many things in electronics are curved,bended and packed to look right but they are not.From here i cant go deeper in this direction.

All i can say is that true audio is true audio when you hear it and say its true of course if you are healthy and have healthy hearing.Any AC feedback in audio output stage is wrong.

Last edited by Mikelandjelo; 11th February 2018 at 01:28 PM.
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Old 11th February 2018, 01:34 PM   #60
scottjoplin is offline scottjoplin  Wales
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Have you any schematics to show us yet?
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