Has anyone built AN-211 current feedback amp ?

[peranders]

Re: Re: alexander current feedback amplifier

can we redesign this amp with latest components ?

Sure you can. I'll bet you can even use tubes!

Nobody answered ! How is the idea of replacing monolithic op-amp with descrete one !

Sure you can

 

[jmd01]

Hi Per-Anders and Prasanna

I want into the discussion of distortion QRV from post12 and 13 specify measurements with THD 0.0005%. I was writing in Anders's thread "Current feedback headphone amp" in post#48 :
http://www.diyaudio.com/forums/showthread.php?postid=784679#post784679

have a nice day

 

[peranders]

Thanks for the reminder Are you still happy with your QRV-06 clone?

 

[peranders]

When I reread my old thread I notice that none of the usual amplifier gurus have commented, not even the man itself. Why is that? Current feedback unknown? I at least really like it!

 

[jmd01]

Hi Per-Anders

I feel bad about it that our measure causes your scepticism. I think we didn't do mistake. The measure was done by great man with unbelievable enthusiasm. He has big experience in his little family firm http://www.bvaudio.sk. I'm delight that he involved into this chat http://www.diyaudio.com/forums/showthread.php?postid=811354#post811354

 

[jmd01]

Hi Per-Anders

I´m still happy with it. I think about Anli's ideas which he wrote on begin in your tread "Current feedback headphone amp". As I wrote, I want to make it better.

 

[peranders]

Re: Hi Per-Anders

I feel bad about it that our measure causes your scepticism. I think we didn't do mistake. The measure was done by great man with unbelievable enthusiasm.

It's always healthy to take a couple of steps backwards and look again at the given results, especially when they are at the limit. I have myself made the conclusion that the design is much better than my soundcard, 0.008%.

 

[wimdehaan]

circuitboard layout Alexander Current Feedback Amp

circuitboard layout Alexander Curuent Feedback Amp

I build this amplifier according to AN-211 application note by Marc Alexander / Analog Devices a long time ago (october 1992). My detailed info was lost due a hard-disc failure, I had no back-up so all info was lost. However last week or so I did discover the orginal print layouts by concidence I didn't know that I still had them. so for those who are interested I did add them to my webpage at www.wdehaan.demon.nl/various/alexcurrentfb/index.html

On my page you can find also a program called Sprint Layout that makes it possible to 'copy' the layout. You might like to check out http://www.wdehaan.demon.nl/various/sprintlayout/index.html

- Wim

 

[Jonathan Bright]

ELECTOR also published a DIY CFB power amp in the 1990's it was about 60-80 watts (8ohms) and also had IGBT in the output stage. All I can remember was the wide frequency response and they drew attention to the poor PSRR of their particular design.