XA.8 single-ended current sources

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Antoinel

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Joined 2011
Zen Mod said:
"main" thing in Aleph CCS is that thingie is modulated ; here is no need for CCS to be modulated , so no possibility to establish Aleph CCS

so , taking aside wittiness needed to make a difference , difference between Aleph CCS and so called Widlar Current Source*** is no more than few strategically placed resistors and one capacitor ........... establishing pole where CCS programing voltage and modulating signal are combined to govern mighty mosfet

;)


edit: *** #3320439
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Widlar [RIP] has a vibrant CV on the web. He is credited for uA709 while at Fairchild.
 
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pr

Member
Joined 2002
"...here is no need for CCS to be modulated..."

That's not quite the point. I make it more precisely:
1. Because the Aleph current source is modulated it can deliver (when set to the typical gain) double current before it clips. So we get clipping at the the same level with an Aleph current source at say 1A bias as with double sized constant current source i.e. 2A in this example. Hence we can make the amplifier smaller or have the double peak output current. I like that.
2. The Aleph current source helps reducing distortions in an amplifier: It virtually reduces the load that the rest of the amplifier sees. That is very cool. A constant current source cannot do that.
 
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Antoinel

Member
Joined 2011
lhquam said:
Any time you make modifications or compositions of circuits the results can be rather different from your expectations. You need to verify the behavior either mathematically, thru simulation, or actual construction.
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Thanks for your reply. I fully agree with your recommendation [and pr's]. I normally skip these key steps of math/sim and go directly from schematic to a rudimentary prototype just to satisfy my curiosity or prove its concept by subjective assessment.

A schematic is a concept which I write from knowledge I learned [primarily] in this thread. Credit goes to the thread's contributors when it is shown to be good/valuable, and blame [if any] rests with me when it is useless. I am glad that you and others are prudent/skeptical, and hopefully view it with a grain of salt [watch that Sodium]. Best to consider it bad/useless until shown otherwise. Fortunately, schematics will keep coming!
 
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Antoinel

Member
Joined 2011
pr said:
I guess, my question in post #263 was overlooked. I think it is an intersting aspect worth a little discussion. So I ask again:

Why no Aleph current source in the XA.8?
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Hello pr. Its patent is US 5,710,522 which was granted on Jan. 20,1998. Add 20 years to its filing date of Jul. 15, 1996 to declare it is the sole property/practice of Nelson S. Pass till ~the break of dawn of Jul. 16, 2016.

I'll study this patent to understand its knowledge, and its possible adaptability for the sake of my curiosity.

Best regards.
 
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