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Old 26th June 2010, 08:03 PM   #1
aandy is offline aandy  United Kingdom
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Default English class D pro audio amp

please can some one explain the wave forms of the test results on this amplifier,think they are poor and are they typical of class D




HTTP://www.abeltronics.co.uk/amptest...f60Q_-_ffa6004


look under amp testing

Last edited by aandy; 26th June 2010 at 08:07 PM. Reason: link
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Old 26th June 2010, 08:43 PM   #2
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Not typical of decent class-d, it's poor amps like this that give class-d a bad name.
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Old 27th June 2010, 06:37 PM   #3
SOSx is offline SOSx  United Kingdom
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Hi Andy,

If you have been looking at this then I am sure that you have also seen the other tests by Abeltronics? He has tested various Class D-amplifiers and only a few have shown these sorts of severe results on a scope. Namely Powers oft and PKN.
I myself run large Lab Gruppen Class D (ish) amps that exhibit none of this.

I myself have also tested the amps in question in blind ab tests (well the 4004 version from FFA) and was not happy with the sound quality. We found its sound to be hard and abrasive above about 3-4k.

There are most definately good and bad ways to design all topologies

Kindest Regards
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Old 27th June 2010, 09:06 PM   #4
aandy is offline aandy  United Kingdom
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I have tested the labs,they are class G were the booster(tracking supplies are pwm based buck converters) are tracking unlike the switched class H.

I like the labs But i am shocked by the utter lack of consideration as too the quality of this amplifier on the albertronics sight.
I used to design Hi-Fi amplifiers many moons ago.
and these days some manufacturers just produce utter Junk.

I think the customer will lose out,maybe the PA industry needs to be well cleaned up.
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Old 27th June 2010, 10:06 PM   #5
SOSx is offline SOSx  United Kingdom
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I was wondering if you would pick up on the Lab Gruppen topology comment.
I thought that that must have been you Andy!
I told you that these amps were hard and abrasive and really do not compare with the PKN and Powersoft current class D designs.

In case you hadn't realized, Tim From Secrets Of Sound Here.
Hows development going?
Hadn't heard from you or Matt in a while?
How are you by the way?
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Old 28th June 2010, 12:13 PM   #6
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A poorly implemented Class-D by those "Engineers" who think designing a switching amplifier is same as linear amp.

The result is obviously as crappy as one could expect.


Whereas,

When things are neatly engineered, the results[My 5KW CLass-D] are somewhat Cool
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Last edited by Workhorse; 28th June 2010 at 12:29 PM.
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Old 28th June 2010, 05:01 PM   #7
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Quote:
Originally Posted by Workhorse View Post
A poorly implemented Class-D by those "Engineers" who think designing a switching amplifier is same as linear amp.

The result is obviously as crappy as one could expect.


Whereas,

When things are neatly engineered, the results[My 5KW CLass-D] are somewhat Cool

Robust results Workhorse.

Keep the good work
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Old 28th June 2010, 05:24 PM   #8
Eva is offline Eva  Spain
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The output signal shown by Workhorse is pre-clipped, it's a valid method to obtain clean clipping, but it does not reveal actual amplifier behaviour.
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Old 28th June 2010, 05:25 PM   #9
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Quote:
Originally Posted by Eva View Post
The output signal shown by Workhorse is pre-clipped, it's a valid method to obtain clean clipping, but it does not reveal actual amplifier behaviour.

Evita, its not "Preclipped" at input or anywhere else , i use another technique to get STICK FREE CLIPPING

Last edited by Workhorse; 28th June 2010 at 05:33 PM.
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Old 28th June 2010, 05:35 PM   #10
81bas is offline 81bas  Germany
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Quote:
Originally Posted by Workhorse View Post
Whereas,

When things are neatly engineered, the results[My 5KW CLass-D] are somewhat Cool
Hi,
would you be able to achieve the same results in clocked design with 25-30 dB of loop gain at 10kHz?
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