A North European friend asked me to show you this schematic.

destroyer X · 3rd October 2004, 02:01 PM

This class A schematic belongs to:

Knut Harald Nygaard.

Under the schematic, wich one have not values writted, you have the site adress to have more informs and the parts list.

Many other amplifiers you will find there, and some instructions about amplifiers classes and current feedback technics

Go there and enjoy yourselves.

Carlos

MikeB · 3rd October 2004, 04:18 PM

Very interesting vas !
But currentfeedback is only used inside vas for local feedback ?
The global feedback is normal NFB.
Nice circuit i think... (except c45 maybe)

Mike

Tube_Dude · 3rd October 2004, 10:54 PM

Quote:

Originally posted by MikeB

The global feedback is normal NFB.

No!...This global feedback is current feedback.

The inverting input has a low impedance ...

MikeB · 4th October 2004, 09:43 AM

What i ment, the outputvoltage is fed back, not the outputcurrent...

Mike

destroyer X · 4th October 2004, 10:09 AM

And is clealy shown, in his site, that the publish material has copyrigth.

This way, guys, i was carefull, only to put a non complete material, to scape from the "Long arm of the law".

The schematic have not the values, the owner name is written there.

If you are interested, please, go to his site and find by yourselves the informations you need.

I cannot evaluate the amplifier, as i did not assemble the unit.

the one that asked me to publish, is a very complicated man , hard to be understood, and the one that asked was not Mr. Knut Nygaard, the schematic owner, whith copyrigth..., and i do not know if Nygaard is happy or not with that.

Beeing this way, i made what i can do, limited by logic reasons.

sorry not to complete the informations.

regards,

Carlos

godzich · 4th October 2004, 10:34 AM

Hi.

Just by looking at the scematic I claim that it is NOT true class A. With this basic circuit solution it would be quite difficult to bias both push and pull stages to be continuously on during swings approaching the supply rails. OK - without the component values it is hard to tell the overall biasing.

Also using the output transistor in common emitter configuration is a little suspicious - it produces distortion an increases the output impedance...

Christian

djk · 5th October 2004, 09:11 AM

The current gain stages look virtually identical to the Threshold S series, except the Threshold ran no global feedback around the output/driver pair.

I like the front end, you could add another pair of FETs to the input if you wanted a balanced input or voltage feedback.

destroyer X · 5th October 2004, 09:45 AM

Some %$@## to me..... and he did not.

Here is the parts.

Go to his site.... he explain there those current feedback and other interesting things.

regards,

Carlos

destroyer X · 5th October 2004, 11:54 AM

Was HALOJOY.

This way, if Big Charlie disappear from our beloved forum, is because i have some connections and friendship with that guy.

And that guy is really complicated as a hell... today he told me i am coward, stupid, idiot and other things more...have to be patient with him.... he is a gênius, this way... hard to understand...and now turn agressive!

Despite of the "others reasons" to my possible "kicking out" that will be published.... the reason, the real one, will be my friendship with that damn guy!

bye.... good bye.... fairewell... so long.....ciao

Carlos

djk · 6th October 2004, 07:03 AM

There is nothing new or original in that circuit.

If someone is giving you a hard time about it, just tell them they're barking up the wrong tree.

4th October 2004, 10:09 AM	#5
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	The one that asked me to put this schematic in our forum was not the owner And is clealy shown, in his site, that the publish material has copyrigth. This way, guys, i was carefull, only to put a non complete material, to scape from the "Long arm of the law". The schematic have not the values, the owner name is written there. If you are interested, please, go to his site and find by yourselves the informations you need. I cannot evaluate the amplifier, as i did not assemble the unit. the one that asked me to publish, is a very complicated man , hard to be understood, and the one that asked was not Mr. Knut Nygaard, the schematic owner, whith copyrigth..., and i do not know if Nygaard is happy or not with that. Beeing this way, i made what i can do, limited by logic reasons. sorry not to complete the informations. regards, Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!

5th October 2004, 11:54 AM	#9
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	The one that asked me to put this thread Was HALOJOY. This way, if Big Charlie disappear from our beloved forum, is because i have some connections and friendship with that guy. And that guy is really complicated as a hell... today he told me i am coward, stupid, idiot and other things more...have to be patient with him.... he is a gênius, this way... hard to understand...and now turn agressive! Despite of the "others reasons" to my possible "kicking out" that will be published.... the reason, the real one, will be my friendship with that damn guy! bye.... good bye.... fairewell... so long.....ciao Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!

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3rd October 2004, 04:18 PM	#2
MikeB diyAudio Member Join Date: Apr 2004 Location: Gütersloh	Very interesting vas ! But currentfeedback is only used inside vas for local feedback ? The global feedback is normal NFB. Nice circuit i think... (except c45 maybe) Mike

4th October 2004, 09:43 AM	#4
MikeB diyAudio Member Join Date: Apr 2004 Location: Gütersloh	What i ment, the outputvoltage is fed back, not the outputcurrent... Mike

4th October 2004, 10:34 AM	#6
godzich diyAudio Member Join Date: Oct 2004	Hi. Just by looking at the scematic I claim that it is NOT true class A. With this basic circuit solution it would be quite difficult to bias both push and pull stages to be continuously on during swings approaching the supply rails. OK - without the component values it is hard to tell the overall biasing. Also using the output transistor in common emitter configuration is a little suspicious - it produces distortion an increases the output impedance... Christian

5th October 2004, 09:11 AM	#7
djk diyAudio Member Join Date: Feb 2001 Location: USA	The current gain stages look virtually identical to the Threshold S series, except the Threshold ran no global feedback around the output/driver pair. I like the front end, you could add another pair of FETs to the input if you wanted a balanced input or voltage feedback.

6th October 2004, 07:03 AM	#10
djk diyAudio Member Join Date: Feb 2001 Location: USA	There is nothing new or original in that circuit. If someone is giving you a hard time about it, just tell them they're barking up the wrong tree.

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