Definition of Class G and Class H

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Gold_xyz

Gold_xyz

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Joined 2005

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kASD

kASD

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Joined 2004
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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B

Bob Cordell

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Joined 2006
cordellaudio.com
Workhorse said:
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
Click to expand...


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
 
Gold_xyz

Gold_xyz

Member
Joined 2005
Workhorse said:
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
Click to expand...
Hi Kanwar :D

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/freeabs_all.jsp?tp=&arnumber=117926&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... :dodgy:
http://www.pcmag.com/encyclopedia_term/0,2542,t=amplifier+classes&i=55350,00.asp
http://www.nfsa.afc.gov.au/glossary.nsf/Pages/Amplifier?OpenDocument
http://www.prg.com/support/education/glossary/audio/a

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
Click to expand...
It would seem that there is need of a standard... :xfingers:
 
kASD

kASD

Member
Joined 2004
Gold_xyz said:

Hi Kanwar :D

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/freeabs_all.jsp?tp=&arnumber=117926&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... :dodgy:
http://www.pcmag.com/encyclopedia_term/0,2542,t=amplifier+classes&i=55350,00.asp
http://www.nfsa.afc.gov.au/glossary.nsf/Pages/Amplifier?OpenDocument
http://www.prg.com/support/education/glossary/audio/a


It would seem that there is need of a standard... :xfingers:
Click to expand...


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
 
kASD

kASD

Member
Joined 2004
Gold_xyz said:
Hi, more news :D

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

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 H/Amp AL.png

bye :car:
Click to expand...

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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Gold_xyz

Gold_xyz

Member
Joined 2005
Workhorse said:
...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...
Click to expand...
From : http://www.diyaudio.com/forums/showthread.php?s=&threadid=68415

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 :snoopy:
 

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