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Old 19th August 2012, 02:31 PM   #691
AP2 is offline AP2  Italy
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Quote:
Originally Posted by liching1952 View Post
Watch before you ahaha..am talking of the end stage not the frontend. The frontend needs a stable and humfree supply but the current demand is stable and low, so its simple to acchieve.
The end stage is an emitter or source follower. The name already says, the output follows the voltage of the basis or gate. The supply is connected to the collector or drain. How could this come to the emitter or source. Look to the y parameters of the transistor or fet.
With respect, I think you need to change books. are studying the basic concepts and old.
this not help you.
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Old 19th August 2012, 02:38 PM   #692
AndrewT is offline AndrewT  Scotland
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Originally Posted by Nico Ras View Post
......... You are definitely making an impression on the members here.
And not a good impression. I feel his reputation, if there ever was one to be associated with, became tarnished with his first post. I bumped into Lin at his second post.
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Old 19th August 2012, 02:40 PM   #693
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Originally Posted by AP2 View Post
With respect, I think you need to change books. are studying the basic concepts and old.
this not help you.
Can you post the article that confirms this?
Have you ever hear of a cascode stage. It consists of 2 fet or transistors with the basis or gate of the 2nd element grounded to cancel the early effect.

Last edited by liching1952; 19th August 2012 at 02:44 PM.
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Old 19th August 2012, 03:03 PM   #694
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Originally Posted by liching1952 View Post
This effect is practically canceled out when the basis is connected to a low impedance which it is in a good design. The basis is driven by an emitter follower with low impedance.
Even with a low impedance driver the effect is still there, its this "practically canceled out" issue.
Personally I don't have great hearing and really cant discriminate between most amps (other than clipping or severe cross-over distortion) but I still enjoy following all these discussions which try to eliminate the slightest potential for distortion.
The pay back is huge in terms of having to keep engineering skills sharp as well as the applicability of many discussed methods to other areas where it is important to me.

So yes the early effect may or may not be significant (equivalent to some -60db) but it sure is helpful to review the impact.

Hope this helps
-Antonio
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Old 19th August 2012, 03:05 PM   #695
alayn91 is offline alayn91  France
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Hello,

Cascode - Wikipedia, the free encyclopedia

Regards.
Alain.
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Old 19th August 2012, 03:35 PM   #696
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Leaving out a SMPS for argument sake as that muddies the water with an Apples and Watermelon discussion, have we come to any consensus on what is preferred a linear or regulated power supply? If not are there at least any preferred topologies for each circuit that us who are not EE's can understand and implement. This argument can go on forever but that won't help those who are trying to build an amplifier or even a good preamp if we can't size the power supply.

I guess I can just follow this argument and hope to get insights into the different approaches. but it would be nice to see some consensus on a few preferred approaches. Otherwise it is transformer, capacitor, rectifier, and make the damned things on the high voltage side, SOA of the output devices and lots of capacitor size and hope for the best....... Just being facetious in that last comment but only partially....


It's not the economy stupid, it's the music I care about. We do have a couple of nabobs trying to win an election here.........
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Old 19th August 2012, 03:51 PM   #697
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Originally Posted by magnoman View Post
Even with a low impedance driver the effect is still there, its this "practically canceled out" issue.
Personally I don't have great hearing and really cant discriminate between most amps (other than clipping or severe cross-over distortion) but I still enjoy following all these discussions which try to eliminate the slightest potential for distortion.
The pay back is huge in terms of having to keep engineering skills sharp as well as the applicability of many discussed methods to other areas where it is important to me.

So yes the early effect may or may not be significant (equivalent to some -60db) but it sure is helpful to review the impact.

Hope this helps
-Antonio
Nothing is perfect in real world. Hum from the powersupply by early effect is down lower then noise and maximum hum occur when playing loud passages, so its not an issue at all. A good engenieer designer knows this and doesnt waste time and money to use for example a so called Capacitance multiplier or what soever which may be blokked that little hum but introduce other problems he doesnt know.
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Old 19th August 2012, 04:14 PM   #698
dadod is offline dadod  Croatia
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Why you guys are losing your time to discus with liching1952? Look at posts $485 and #487 haw he calculate power on 0.1 ohm which is in series with the power supply and the output power with the power supply of +-50 V(forget about c multiplier losses) , he is total ignorant or just trying to provoke or disrupt this thread.
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Old 19th August 2012, 04:26 PM   #699
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Originally Posted by dadod View Post
Why you guys are losing your time to discus with liching1952? Look at posts $485 and #487 haw he calculate power on 0.1 ohm which is in series with the power supply and the output power with the power supply of +-50 V(forget about c multiplier losses) , he is total ignorant or just trying to provoke or disrupt this thread.
Yes am still waiting for an answer of my question in post 487 mr Dadod. Kan jij een antwoord geven meneer Dadod?
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Old 19th August 2012, 04:27 PM   #700
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Quote:
Originally Posted by liching1952 View Post
Nothing is perfect in real world. Hum from the powersupply by early effect is down lower then noise and maximum hum occur when playing loud passages, so its not an issue at all. A good engenieer designer knows this and doesnt waste time and money to use for example a so called Capacitance multiplier or what soever which may be blokked that little hum but introduce other problems he doesnt know.
However a good engineer doesn't assume this, but rather analyzes the issue and tries to understand all aspects (wasn't really thinking about hum). Eventually a compromise is reached which results in what he or she believes is the optimal solution to accomplish their goal, accounting for the given constraints (including time and money).

Hope this helps
-Antonio
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