Current feedback class A monoblocks

JGuilherme · 26th August 2012, 10:12 PM

Based on a design by Knut Harald Nygaard. Frequency range from dc to above 1 Mhz, 40W output, slewrate 200 V/uS. Been on my system for the past three or so years, having replaced a Plinius integrated. They sound exceptionally good to me, hope you like the pics.

DUG · 26th August 2012, 11:56 PM

Nice and clean...in and out

a.wayne · 27th August 2012, 04:14 AM

Sweet .....

homemodder · 27th August 2012, 01:59 PM

Which of Knut s designs is used, the no feedback one ?? Most of his designs look very good indeed.

Bigun · 27th August 2012, 03:52 PM

Judging only by the thread title, I'd hazard a guess the design is fig. 4.4. of this article:

DC Coupled Amplifiers for Audio

bear · 27th August 2012, 05:28 PM

no, this one:

Voltage Amplifier & Current Buffer DIY

AndrewT · 27th August 2012, 06:26 PM

The voltage amp (post6) stage looks like it shows the out>> must be connected to the in<< This is global feedback. Or have I read the schematic wrongly?

knutn · 27th August 2012, 06:38 PM

Since its my current feedback design, I think it must be this one(?): Power Amplifier

bear · 27th August 2012, 07:11 PM

Well, if anyone would know, it would be you!

So, have you done a FFT of the harmonics?

And, what is ur position on the relatively high THD figure of 0.02%?
How does that look at a higher freq, btw?

Asking a few other things too...

why not an F5 (similar power level, lower parts count, and same input pretty much)

and also... aw crud, lost the thought...

interesting design idea...

_-_-bear

JGuilherme · 27th August 2012, 10:16 PM

Quote:

Originally Posted by knutn

Since its my current feedback design, I think it must be this one(?): Power Amplifier

Lol, yes, that's the one. Only difference is that I doubled the output transistors and added some bells and whistles to it.

I didn't know you posted here, so I'll take the chance to congratulate you on a wonderful design. This was my third attempt at trying to build something that would replace the Plinius. I built the Hiraga 20W which sounded very sweet, but didn't have enough power, then the KSA50 which I hated, and then yours, which I fell in love right from the first moment I heard it.

At first I didn't want to waste money on the front pannels because I wasn't sure if it would be just a fad, but three years latter I think they deserved a nice face plate. So I ordered some and took some pics while I was at it, hence this thread now. (btw, where are all my posts from back then???).

The monoblocks are being driven by a preamp based on Walt's composite with the AD811 and are driving a couple of ATC SCM12 monitors.

26th August 2012, 11:56 PM	#2
DUG diyAudio Member Join Date: Jan 2003 Location: mississauga ontario canada	Nice and clean...in and out __________________ Doug We are all learning...we can all help

27th August 2012, 03:52 PM	#5
Bigun diyAudio Member Join Date: Jan 2009 Blog Entries: 2	Judging only by the thread title, I'd hazard a guess the design is fig. 4.4. of this article: DC Coupled Amplifiers for Audio __________________ "The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.

27th August 2012, 05:28 PM	#6
bear expert in tautology diyAudio Member Join Date: Apr 2002 Location: New York State USA	no, this one: Voltage Amplifier & Current Buffer DIY __________________ _-_-bear http://www.bearlabs.com [...2SJ74 Toshiba bogus asian parts - beware! ] -- Btw, I don't actually know anything, FYI --

27th August 2012, 07:11 PM	#9
bear expert in tautology diyAudio Member Join Date: Apr 2002 Location: New York State USA	Well, if anyone would know, it would be you! So, have you done a FFT of the harmonics? And, what is ur position on the relatively high THD figure of 0.02%? How does that look at a higher freq, btw? Asking a few other things too... why not an F5 (similar power level, lower parts count, and same input pretty much) and also... aw crud, lost the thought... interesting design idea... _-_-bear __________________ _-_-bear http://www.bearlabs.com [...2SJ74 Toshiba bogus asian parts - beware! ] -- Btw, I don't actually know anything, FYI --

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27th August 2012, 04:14 AM	#3
a.wayne diyAudio Member Join Date: May 2008 Location: Front Row Center	Sweet .....

27th August 2012, 01:59 PM	#4
homemodder Account disabled at member's request Join Date: May 2006	Which of Knut s designs is used, the no feedback one ?? Most of his designs look very good indeed.

27th August 2012, 06:26 PM	#7
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	The voltage amp (post6) stage looks like it shows the out>> must be connected to the in<< This is global feedback. Or have I read the schematic wrongly?

27th August 2012, 06:38 PM	#8
knutn diyAudio Member Join Date: Mar 2006 Location: Oslo	Since its my current feedback design, I think it must be this one(?): Power Amplifier

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