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Old 25th January 2013, 05:12 AM   #1
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Default low THD and no global feedback amp

Recently designed a circuit, the circuit reference circuit of a lot of friends, and very grateful to them, and also get a lot of help and inspiration from them.The circuit design principle is to make use of the already resource.
I already have three pairs Marantz HDAM-SA2 modules current, so I try to design the circuit this resource. Requirements of the circuit is the lowest possible distortion, high speed, and the best possible sense of hearing; so I decided this circuit uses a current-mode circuit, the input of the current signal input, output IV transform output amplified voltage signal to take no global feedback circuit configuration.
Circuit basic structure:
Actual production my input signal of the voltage type, and so the input by adding a buffer input terminal, the input of this buffer is a HDAM-SA2 module.
In order to better match the output IV transform a buffered output of the module HDAM-SA2 structure, so the whole diagram is as follows.

the picture at #7

Last edited by thinkhlin; 3rd February 2013 at 12:29 PM.
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Old 25th January 2013, 07:53 AM   #2
The Dastardly Dad of Three
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cannot see your links there matey
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Old 25th January 2013, 08:56 AM   #3
Mooly is offline Mooly  United Kingdom
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Old 25th January 2013, 09:06 AM   #4
Boscoe is offline Boscoe  United Kingdom
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What do people have against feedback?
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I thought about it once, but then thought again.
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Old 25th January 2013, 09:59 AM   #5
DF96 is offline DF96  England
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People always have an irrational fear of something they don't understand. There are even people who are afraid of capacitors.
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Old 25th January 2013, 11:19 AM   #6
wahab is offline wahab  Algeria
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When i read "no feedback" sticked with "low distorsion" i ve got some alarm
that start to ring...

Quote:
Originally Posted by thinkhlin View Post
Requirements of the circuit is the lowest possible distortion,
This requirement is not compatible with a feedbackless topology.

Either you have low distorsions with feedback or inherently way
higher distorsions ratios if no feedback is used.
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Old 27th January 2013, 01:35 AM   #7
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Oh, everybody! I'm so sorry!
Attached Images
File Type: png AllInOne.png (47.9 KB, 325 views)
File Type: png baseimg.png (37.0 KB, 320 views)
File Type: png HDAM-SA2.png (16.3 KB, 316 views)
File Type: png THD.png (19.9 KB, 312 views)
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Old 27th January 2013, 01:36 AM   #8
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Quote:
Originally Posted by kasey197 View Post
cannot see your links there matey
en~~~,I post it thank you!
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Old 27th January 2013, 01:37 AM   #9
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Quote:
Originally Posted by Mooly View Post
Add your pictures directly

"To add a photo, files or non standard files.

First click "go advanced" in the box below the "quick reply" message box. Doesn't matter if you decide half way through a message to do that, it carries it foward.

Then click "Manage attachements". Maximise the new Window so that you can see all the text.

Click browse in the first box at the top and find your picture. Repeat for any more pictures.
Click upload... a message appears "uploading"
When complete the files will show as being attached. Now click the small text that says "close this window"

The pictures should now be attached and when you submit your post they will appear.

Make sure your pics aren't too big, a couple of 100k is plenty, and many members object when they are massive and it alters the margins
It tells you in the attachments window what max sizes are allowed.


If you want to attach a file that has a non standard format for example excel, circuit simulation etc then try putting the files in a zipped folder and attaching that. "
thank you!
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Old 27th January 2013, 01:38 AM   #10
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Quote:
Originally Posted by Boscoe View Post
What do people have against feedback?
hi Boscoe!
No feedback to achieve low distortion, the closed-loop distortion I believe will be lower.
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