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Old 16th January 2007, 05:35 AM   #1
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Default Definition of Class G and Class H

Hallo !

The perfect definition of Class G and class H is hard to find...

The Class - H Amplifier
class H design


I have this good document found :
http://www.rane.com/par-a.html
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Old 16th January 2007, 11:04 AM   #2
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Hello GOLD_XYZ,

In your diagram you shown the waveforms associated with the working of classes is wrong......

Class-H has Square Step Envelope....

While

Class-G has Linear Step Envelope


This is the correct one....


K a n w a r
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Old 16th January 2007, 09:05 PM   #3
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Quote:
Originally posted by Workhorse
Hello GOLD_XYZ,

In your diagram you shown the waveforms associated with the working of classes is wrong......

Class-H has Square Step Envelope....

While

Class-G has Linear Step Envelope


This is the correct one....


K a n w a r

I believe that the US and Japanese definitions of Class G and Class H are swapped.

I can never keep track of it myself. I think Duncan covered it in his book.

I worked on the Crest 8001, which had three sets of rails. The upper rails moved in an analog fashion (they were not hard-switched). Crest referred to their amplifier as Class H.

Bob
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Old 17th January 2007, 06:41 AM   #4
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Quote:
Originally posted by Workhorse
Hello GOLD_XYZ,

In your diagram you shown the waveforms associated with the working of classes is wrong......

Class-H has Square Step Envelope....

While

Class-G has Linear Step Envelope


This is the correct one....


K a n w a r
Hi Kanwar

I know well what you say.

In this site it says (class H) "electronic switching between multiple rail voltage levels"
http://ieeexplore.ieee.org/xpl/freea...&isnumber=3398

the problem is that in many sites he is otherwise written..
http://www.rane.com/par-a.html
it says
"class G = rail switcher, class H = rail-tracker"
also wikipedia
http://en.wikipedia.org/wiki/Electronic_amplifier
and many others...
http://www.pcmag.com/encyclopedia_te...i=55350,00.asp
http://www.nfsa.afc.gov.au/glossary....r?OpenDocument
http://www.prg.com/support/education/glossary/audio/a

Quote:
Originally posted by Bob Cordell
I believe that the US and Japanese definitions of Class G and Class H are swapped.

I can never keep track of it myself. I think Duncan covered it in his book.

I worked on the Crest 8001, which had three sets of rails. The upper rails moved in an analog fashion (they were not hard-switched). Crest referred to their amplifier as Class H.

Bob
It would seem that there is need of a standard...
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Old 17th January 2007, 07:27 AM   #5
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Quote:
Originally posted by Gold_xyz

Hi Kanwar

I know well what you say.

In this site it says (class H) "electronic switching between multiple rail voltage levels"
http://ieeexplore.ieee.org/xpl/freea...&isnumber=3398

the problem is that in many sites he is otherwise written..
http://www.rane.com/par-a.html
it says
"class G = rail switcher, class H = rail-tracker"
also wikipedia
http://en.wikipedia.org/wiki/Electronic_amplifier
and many others...
http://www.pcmag.com/encyclopedia_te...i=55350,00.asp
http://www.nfsa.afc.gov.au/glossary....r?OpenDocument
http://www.prg.com/support/education/glossary/audio/a


It would seem that there is need of a standard...

The STANDARD is well maintained as

Class-H = Square Step Envelope
Class-G = Linear Step Envelope
Class-TD= Rail Modulating Envelope...[Tracking Rail]

And stick to it as its Right.....
The other references are just an example of confused or misunderstood concepts...

regards,
K a n w a r
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Old 19th January 2007, 07:10 AM   #6
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Hi, more news

...The first Class-G design into production by Hitachi
I need to find a schematics of "Dynaharmony HMA 8300 power amplifier"

I think that the first definition of the class H is with a multilevel switched supply... to see Pat. 3.319.175

In Soundcraftsmen MA5002 (Class-H) I see only a rail-tracking by Q19 - Q20 - Q21
http://www.soundcraftsmen.info/Class%20H/Amp%20AL.png

bye
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Old 19th January 2007, 01:39 PM   #7
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Quote:
Originally posted by Gold_xyz
Hi, more news

...The first Class-G design into production by Hitachi
I need to find a schematics of "Dynaharmony HMA 8300 power amplifier"

I think that the first definition of the class H is with a multilevel switched supply... to see Pat. 3.319.175

In Soundcraftsmen MA5002 (Class-H) I see only a rail-tracking by Q19 - Q20 - Q21
http://www.soundcraftsmen.info/Class%20H/Amp%20AL.png

bye
If you look at the waveforms of Soundcraftsmen Class-h amp...they exhibit square step type envelope, not a linear envelope , therefore its Class-H
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Old 20th January 2007, 08:30 AM   #8
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A little simulation with pspice of supply "lifter" of Soundcraftsmen MA5002 (Class-H)

Click the image to open in full size.

this is undoubtedly a rail tracker...

and Pspice schematics..
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Old 20th January 2007, 09:13 AM   #9
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Quote:
Originally posted by Workhorse
...I mean to say in simple words "The Rail Switcher Amp" benefits from the elimination of wasted heat incase of class-AB , by splitting the power rails into 2 or 3 TIERS, and choosing the appropriate Rail according to the Voltage Swing at output.....So that the output transistor has less VCE across it to do the job with less wastage...
From : The Class - H Amplifier

Hi, Workhorse,
Your definition is right !

With two or more rail switcher (that approx. the envelope) or with a
rail tracker is a class H amplifier. (to see Pat. 3.319.175)
With a single rail switcher is a class G.

bye
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