Class D Vs Class I (Balanced Current Amplifier)

rmsaudio · 25th September 2006, 03:33 AM

Was wondering if any electronics engineers could offer some technical opinions
on the subject.

Which topology is better, class-d, class-i or even class-h ?

From my limited experience in audio, I've learned that most arguments come
down to application, but since they're all a form of digital, perhaps there is
a "better" choice. When I say better, I'm thinking manufacturing costs,
reliability, sound quality and THD etc. Perhaps Class-I is just marketing hype?

I've been toying with the idea of contracting out some designs, hence the question. Application would be _big_ sound...pubs, clubs, events
and competition car audio. The dream is something along the lines of crown's
i-tech and JBL's 6KW beast http://www.caraudiomag.com/specialfe.../photo_03.html ....probably not quite so big, but along competition lines.

Workhorse · 25th September 2006, 04:01 AM

Well,

Class-D is Classical Pulse Width Modulation switching amplifier...Its output consists of Mosfets in Pushpull manner and a series connected Inductor filter to retrieve the audio wave from the Pulsating signal through averaging effect of inductor.Efficiency is around 90-95%.....

Class-I is just another hyped version of Class-D but it uses two large inductors for storing energy as the both output mosfet conduct at same time, though absence of dead-time, but its high frequency response is not good one.....Its also Known as Balanced Current amplifier [BCA]...

Class-H is actually a Class-AB amplifier whose supply rails were switched from lower level to upper level in accordance with the output voltage required to get efficiency.....2 Tier Class-H is Efficient upto
65-75% with music signals

I have developed both Class-D and Class-H amplifiers......

regards,
K a n w a r

TOINO · 25th September 2006, 02:10 PM

When I look for “class-I” schematics, the only thing I see is two Buck regulators bridge connected…
One positive the other negative, like class-B analog amplifier.

Could some body tell me if I need eyeglasses, please..?

jmartins · 25th September 2006, 06:15 PM

Where can I read more about Class-H ?

There is schematics ? websites???

regards,
João

TOINO · 25th September 2006, 06:49 PM

Oi João...

http://www.qscaudio.com/support/tech...rt/schems1.htm

Workhorse · 25th September 2006, 06:52 PM

Quote:

Originally posted by TOINO
When I look for “class-I” schematics, the only thing I see is two Buck regulators bridge connected…
One positive the other negative, like class-B analog amplifier.

Could some body tell me if I need eyeglasses, please..?

Hi TOINO,

www.crownaudio.com/pdf/amps/137234.pdf
www.crownaudio.com/pdf/amps/137331.pdf

Quote:

Originally posted by jmartins
Where can I read more about Class-H ?

There is schematics ? websites???

regards,
João

In mY Thread

The Class - H Amplifier

regards,
K a n w a r

rmsaudio · 25th September 2006, 07:30 PM

Workhorse: thanks for the input, I remember you as ampman ...from a few
years back, glad to see you're still alive and kicking!

Perhaps drop me an email when you get a chance, design@rmsaudio.com. I
did try and email you, but the forum didn't allow it.

Workhorse · 25th September 2006, 07:37 PM

Hi RMS,

Nice to see you too..........

email me at

info@workhorsetechnologiesindia.com

for any enquires....

It seems to me that you also changed your Identity as your registration is dated to 2006...and you say you know me from past few years

regards,
K a n w a r

TOINO · 25th September 2006, 07:50 PM

Hi Workhorse

Yes I know all the Crown “pa-ta-ti-bla-bla”, but analysing the schematics: http://www.jblproservice.com/pdf/Ver...Schematics.pdf
Is just two Buck converters assembled like a class-AB output “linear” power amplifier.
On class-AB you have 1 power transistor for positive part of signal and another for negative.
Positive one could only source current to load=Class-I positive Buck converter.
Negative one could only sink current from load= Class-I negative Buck converter.
For my eyes, class-I looks like a switched class-AB counterpart in which the output transistors are Buck-converters.
Even the modulation scheme is in a way to simulate the linear class-AB amplifier.

Workhorse · 26th September 2006, 04:16 AM

Hi TOINO,

Yes your right, but have you noticed one thing that the two mosfets switch at same time .......but the Pulse width changes according to the signal

Do you have RAM audio schematics....

regards,
K a n w a r

25th September 2006, 03:33 AM	#1
rmsaudio diyAudio Member Join Date: Sep 2006	Class D Vs Class I (Balanced Current Amplifier) Was wondering if any electronics engineers could offer some technical opinions on the subject. Which topology is better, class-d, class-i or even class-h ? From my limited experience in audio, I've learned that most arguments come down to application, but since they're all a form of digital, perhaps there is a "better" choice. When I say better, I'm thinking manufacturing costs, reliability, sound quality and THD etc. Perhaps Class-I is just marketing hype? I've been toying with the idea of contracting out some designs, hence the question. Application would be _big_ sound...pubs, clubs, events and competition car audio. The dream is something along the lines of crown's i-tech and JBL's 6KW beast http://www.caraudiomag.com/specialfe.../photo_03.html ....probably not quite so big, but along competition lines.

25th September 2006, 04:01 AM	#2
Workhorse diyAudio Member Join Date: Dec 2004 Location: ḺΛβ	Re: Class D Vs Class I (Balanced Current Amplifier) Well, Class-D is Classical Pulse Width Modulation switching amplifier...Its output consists of Mosfets in Pushpull manner and a series connected Inductor filter to retrieve the audio wave from the Pulsating signal through averaging effect of inductor.Efficiency is around 90-95%..... Class-I is just another hyped version of Class-D but it uses two large inductors for storing energy as the both output mosfet conduct at same time, though absence of dead-time, but its high frequency response is not good one.....Its also Known as Balanced Current amplifier [BCA]... Class-H is actually a Class-AB amplifier whose supply rails were switched from lower level to upper level in accordance with the output voltage required to get efficiency.....2 Tier Class-H is Efficient upto 65-75% with music signals I have developed both Class-D and Class-H amplifiers...... regards, K a n w a r

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25th September 2006, 02:10 PM	#3
TOINO diyAudio Member Join Date: Oct 2004 Location: Coimbra	When I look for “class-I” schematics, the only thing I see is two Buck regulators bridge connected… One positive the other negative, like class-B analog amplifier. Could some body tell me if I need eyeglasses, please..?

25th September 2006, 06:15 PM	#4
jmartins diyAudio Member Join Date: Apr 2005 Location: São Paulo	Where can I read more about Class-H ? There is schematics ? websites??? regards, João

25th September 2006, 06:49 PM	#5
TOINO diyAudio Member Join Date: Oct 2004 Location: Coimbra	Oi João... http://www.qscaudio.com/support/tech...rt/schems1.htm

25th September 2006, 07:30 PM	#7
rmsaudio diyAudio Member Join Date: Sep 2006	Workhorse: thanks for the input, I remember you as ampman ...from a few years back, glad to see you're still alive and kicking! Perhaps drop me an email when you get a chance, design@rmsaudio.com. I did try and email you, but the forum didn't allow it.

25th September 2006, 07:37 PM	#8
Workhorse diyAudio Member Join Date: Dec 2004 Location: ḺΛβ	Hi RMS, Nice to see you too.......... email me at info@workhorsetechnologiesindia.com for any enquires.... It seems to me that you also changed your Identity as your registration is dated to 2006...and you say you know me from past few years regards, K a n w a r

25th September 2006, 07:50 PM	#9
TOINO diyAudio Member Join Date: Oct 2004 Location: Coimbra	Hi Workhorse Yes I know all the Crown “pa-ta-ti-bla-bla”, but analysing the schematics: http://www.jblproservice.com/pdf/Ver...Schematics.pdf Is just two Buck converters assembled like a class-AB output “linear” power amplifier. On class-AB you have 1 power transistor for positive part of signal and another for negative. Positive one could only source current to load=Class-I positive Buck converter. Negative one could only sink current from load= Class-I negative Buck converter. For my eyes, class-I looks like a switched class-AB counterpart in which the output transistors are Buck-converters. Even the modulation scheme is in a way to simulate the linear class-AB amplifier.

26th September 2006, 04:16 AM	#10
Workhorse diyAudio Member Join Date: Dec 2004 Location: ḺΛβ	Hi TOINO, Yes your right, but have you noticed one thing that the two mosfets switch at same time .......but the Pulse width changes according to the signal Do you have RAM audio schematics.... regards, K a n w a r

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