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Old 12th February 2013, 02:04 PM   #301
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If yo u want the Aleph sound, why not just make Aleph JX? I truly dont know how to imporve the efficiency of a buffer, but that dosn't mean it cant be done.
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Old 12th February 2013, 02:16 PM   #302
Itsmee is offline Itsmee  England
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Quote:
Originally Posted by Alettagla View Post
But can anyone help me out on the original questions why adding an aleph current source to just the buffer stage doesn´t work and results in an occilation.
You would need to post a schematic of your modifications before anyone can comment.

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Originally Posted by Nelson Pass View Post
You will get a lot more efficiency out of BA#2, which is push-pull instead of single-ended/constant current source.

If you want more efficiency out of the all-N channel output stages, we will expect to be doubling the efficiency in a later version.
As I said earlier, change the topology to a quasi push pull output.
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Old 12th February 2013, 02:32 PM   #303
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Thanks for your suggestion but I do not necessarily want the aleph sound. alltough a newby a big part of all this hassle is because I want to learn and be able to know whats going on in these circuits.

But again not to just build someones (Nelsons) design and then settle with it but to learn, and have fun in the proces of learning.


Buzzforb, Thanks for your input so far and hope that when you suddenly get struck by and idea of how to increase efficiency you will let me know.

I hope someone else out there will be able to answer my questions.
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Old 12th February 2013, 02:40 PM   #304
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Last edited by Itsmee; 12th February 2013 at 03:04 PM.
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Old 12th February 2013, 02:40 PM   #305
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the post you quote by Nelson Pass looks old enough that the mentioned 'later version' could be the relatively new BA-3, which basicly is a new frontend combined with output from either BA-1 or BA-2
and now a bit later cascoded input and additional driver for the turbo charged F5 ... and maybe all variations of going balanced as well

is that the effieciency you ask about ?
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Old 12th February 2013, 02:43 PM   #306
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Itsmee, you responded whilst I was typing.

For the moment I hope someone will put me on a track where I can explore further into increasing the efficiency of BA1.


The schematic of how I tried to add an aleph current source wil follow Later
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Old 12th February 2013, 02:47 PM   #307
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Tinitus

Ba3 does in no way incease the efficiency of the all N channel output.
(also bridging or turning it into a balanced version is for as far as I know something different than increasing efficiency)

Last edited by Alettagla; 12th February 2013 at 02:51 PM.
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Old 12th February 2013, 02:51 PM   #308
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How do you propose to increase the efficiency of a buffer?
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Old 12th February 2013, 03:01 PM   #309
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Papa's quote is fairly old - 21st April 2009, 09:29 PM, but he does not always release circuits in a linear fashion (sorry, no pun intended).

The only way to increase the efficiency of the BA1 (as far as I know) to the same as the BA2 is to configure it as a quasi output.

Link to AmpsLab c200.1 Quasi-Complementary 200Watts Power Amp Schematics

Last edited by Itsmee; 12th February 2013 at 03:06 PM.
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Old 12th February 2013, 03:03 PM   #310
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So modulate the lower Fet, which is the CS in this case. If he was trying to modulate the top Fet, I can see having problems.
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