Waly, lets not get into an argument over this. Look up Leach, Google a bit etc. I am not going to discuss this any further with you. My post is not challenge to you or anyone else.
I hope there is CFA using current transformer somewhere. Then it will rename this controversial feedback amp and take over CFA name with it.
It is just high frequency isolation using inductor, there are no current dumped, the current is still flow.
Seems that Current is means Controversial in Audio World😀.
OK I've changed the isolation to another place: 0.0006%THD 20k, still oldie slowie OP devices with 0mA bias.
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CFA is an amplifier in which feedback signal is applied to the output of the input amplifying-subtracting device (whatever this is BJT, fet, OP amp, etc.), period.
OT
And here another amp with output current sensing. Also in this case, its sole purpose is controlling the output bias current.
Cheers, E.
And here another amp with output current sensing. Also in this case, its sole purpose is controlling the output bias current.
Cheers, E.
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Hehehe. Why bothered with the name. This thread is a failure if it cannot reveal what makes some circuits (called by some as CFA) sound preferable. It is not about CFA versus VFA!
Take one benefit that OS has just find out with his new "CFA" toy. It is stable even without compensation. Now any of you have an idea about the "sound" of any compensation types?
Just because it is a CFA does not guarantee it will sound better. The circuit posted by ontoaba is one example 😀
Just make a little effort and try to be technically accurate and I promise I will not step again on your toes (and nerves, probably).
Waly
Technical accuracy is not important, nor is semantics, just who appointed you the police in that?
Are you happy everyone here knows you do not like the term CFA? Do you know what WTF means.... "Waly The Fiduciary" to terms not liked
You keep saying you will not post any more and every time anyone turns around you are back to poke prod and express your dislike of the CFA term. ad nauseam prn and I think you do it for the attention.
Technical accuracy is not important, nor is semantics, just who appointed you the police in that?
Are you happy everyone here knows you do not like the term CFA? Do you know what WTF means.... "Waly The Fiduciary" to terms not liked
You keep saying you will not post any more and every time anyone turns around you are back to poke prod and express your dislike of the CFA term. ad nauseam prn and I think you do it for the attention.
Very interesting opinion regarding technical accuracy.
Please show where I said I don't like CFA's (term, performance, quality, etc...). From where I sit you can call it GVX if you like, it doesn't matter. What I really dislike is attributing to an otherwise accepted marketing concept of CFA (who am I to debate hundreds of millions of deployed DSL devices?) some magical audio properties, when in fact what is called here a "CFA" has only a faint resemblance to the original. All the well known CFA properties are either missing, not used or present only to account for a few percent of the overall result. They are all VFA's, with a particular circuit topology, allowing for uselessly high slew rates. Many properties that are known to drive "good sound" (examples: distortion cancelling in current mirror loaded long tail pairs, high PSRR and CMRR, low noise, etc...) are thrown away, only for rubber stamping the CFA acronym. Another member mentioned that a few years ago, on this very same forum, only mentioning the CFA acronym would throw you to the dogs. Today, it seems to be here the new buzzword, even driving sales! Does this sound like marketing and fashion, or what?
More like "fun". Although it resembles at time poking a hornet's nest.
I like Wally posts, it open one's eyes, technically on the level, and way to get angry about different technical argument and opinion, just stay off subjective judgment.
IMHO
Waly has done NOTHING to advance the technical and or engineering aspects of this thread.
His post reflect his dislike of the semantics or terms used to discuss those aspects.
He is well aware that his extreme pertinacity in doing so "distracts" from the advancement of purpose of the thread. Having to stop or even think about what he is saying detracts from the flow. He says nothing positive, and nit picks every thing said that does not conform precisely to his thoughts.
Hopefully soon there will be some listening done and his instigations will become even more irrelevant to some, and maybe even me.
Waly has done NOTHING to advance the technical and or engineering aspects of this thread.
His post reflect his dislike of the semantics or terms used to discuss those aspects.
He is well aware that his extreme pertinacity in doing so "distracts" from the advancement of purpose of the thread. Having to stop or even think about what he is saying detracts from the flow. He says nothing positive, and nit picks every thing said that does not conform precisely to his thoughts.
Hopefully soon there will be some listening done and his instigations will become even more irrelevant to some, and maybe even me.
Trouble is listening tests are very subjective and what some like others won't.
IMHO technical arguments are more precise and should always have a logical basis that can be proven correct or not either by direct measurement or by mathematics.
And here another amp with output current sensing. Also in this case, its sole purpose is controlling the output bias current.
Cheers, E.
Hey... that's mine 🙂 [Developed and build in (or before) 1981].
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Thats an obvious copy of the Cyrus CFA range of amps, even the component values are the same. Cant Apex just for once post a schematic he didnt copy from some manufacturer. 😀😀😀
Yes, once again, we are on the same tune, damn simple.
Well, let's print:
CFA is an amplifier in which feedback signal is applied to the output of the input amplifying-subtracting BUFFER (whatever this is BJT, fet, OP amp, etc.).
Just to make sure feedback is not applied to the collector/drain etc...
As an ideal CFA has a 0 output impedance, it is just stupid to consider the feedback signal as an image of the output current.
That's just to funny to resist
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