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#1 DjLeco

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Posted 04 January 2011 - 05:08 PM

http://www.prescomaudio.com/webadmin/documents/class_i.pdf

Is this correct, and under laws?

Class I is still under pattent of CROWN, or not?

#2 Kevin Heber

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Posted 05 January 2011 - 09:20 AM

Interesting.  However, the process they describe appears to be totally different than Crown's Class I.   Essentially they describe a linear output stage  (based on Class AB) using BJT's combined with a high-speed switching drive circuit similar to Class D.   Crown's Class I has a switching, interleaving drive circuit (thus the name Class I)and a switching FET output stage.

Looking at the two from 50,000 feet, Crown's Class I is going to yield better efficiency (during use, especially at high power levels -- at idle, Crown's Class I amps must go into standby after a short time to conserve power).  Crown Class I will also have better damping and handle reactive loads better.  My guess is also better low-signal-level performance and less EMI than the Chinese Class I.  In terms of overall complexity, they are probably similar, although Crown's Class I seems like a more elegant approach since it is not merely combining two existing technologies in series, but rather it is an entirely novel drive/switching output topology.

Bottom line:  the two technologies are completely different except for the name.

#3 DjLeco

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Posted 07 January 2011 - 12:24 PM

I know class I topology.
I was afraid they have stollen your pure class I, demanding is their design...
Class I is unique and is ballanced curent amplifier, pure switching amplifier.

No any AB class+switching rails or other implementation, inspired from XTI series, or like Labgruppen, AB+D class.
That's why I was scarred, because Class I is the only one class with balanced curent on output stage.

Btw, class I is under patent, or patent has expired?