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500W (4ohm) GaN Class D Modules - Starkrimson Ultra

SIY

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voodooless

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In any case, why do you think his results will be different than mine? We use the same equipment.

The result might be similar, the reach is definitely not. You might or might not care, but marketing wise it will definitely make a difference.

Edit: almost forgot to comment of the measurements :facepalm:. They look very impressive indeed. Nice job!
 
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restorer-john

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Impressive @orchardaudio :)

The THD vs Frequency @10W graph however is a little deceptive IMO.

Clearly your measurement bandwidth is ~20KHz as the harmonics are falling off the plot above 10kHz (the two measurement points at 15kHz and 20kHz). The trajectory of the plot would suggest 0.02%-0.05% THD or greater up to 20kHz...

1614238298136.png


Can you show a high power (not just 10W) THD vs Frequency sweep with a decent measurement bandwidth?
 

JohnYang1997

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Impressive @orchardaudio :)

The THD vs Frequency @10W graph however is a little deceptive IMO.

Clearly your measurement bandwidth is ~20KHz as the harmonics are falling off the plot above 10kHz (the two measurement points at 15kHz and 20kHz). The trajectory of the plot would suggest 0.02%-0.05% THD or greater up to 20kHz...

View attachment 114751
As long as his not using A weighting. Although it can be somewhat not technically right. But if you think from human hearing perspective, the harmonics are over 20khz so not audible no matter what amplitude. It would be great if we have an overlay of 90KHz bandwidth measurement here so we can get a better picture. A little deceptive I say probably yes.

Take a look at this. Hope this doesn't get your blood boiling.
A30-_-ENG_10_2048x2048 (1).jpg

https://www.audiosciencereview.com/...lifier.16142/#lg=_xfUid-11-1614238809&slide=0
 

Music1969

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Did you know that measurements for my previous amp were verified by a third party (@SIY)?
https://audioxpress.com/article/fre...d-audio-bosc-and-purifi-audio-eigentakt-eval1

Thanks. Please note I'm not questioning your measurements.

But you asked why and I shared an example where Amir's differed from the designer's own measurements, both with APx555

Your amp looks really impressive.

I just wish it came with a power adapter that's safety certified for Australia.

Unless I can find an alternative PSU with correct DC plug
 

JohnYang1997

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I have other equipment I can send to him like PecanPi USB/SPDIF, he has not responded to my messages. So no.

In any case, why do you think his results will be different than mine? We use the same equipment.
Nah. You know what it is.
May I have a dashboard with 4Ohm 5W with 22KBW?
Same equipment but different test conditions will result in drastically different results.
 
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orchardaudio

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Lambda

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Whats the switching frequency? 500K-1Mhz i would guess?

Looks real clean and nice btw ;)
 

bunkbail

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Vini darko

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Good to see this coming along nicely. Measurments look very good. Like the simple case work.
However thread title says 500W @4ohm. I don't see that claim verified in the provided data. Give her all full head of steam both channels loaded :D
 
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orchardaudio

orchardaudio

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However thread title says 500W @4ohm. I don't see that claim verified in the provided data. Give her all full head of steam both channels loaded :D

Can't do much of anything right now, the power supply that I was using for my testing died, so I am investigating this at the moment. Will be a little while before I can get back to it.
 

ShadowFiend

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Very impressive. I would like to ask some question.

1. Can your amplifier drive the 2-Ohm load safely? If yes, how much power it can produce within distortion of 0.1% at 2-Ohm load?
2. Even if the efficiency of your class-D is very high, I would like to ask if there is an easy way to mount your amplifier module to a large heatsink to keep the amplifier cool when driving high load long time.
3. What is the CMRR of your amplifier module at 100 Hz, 1000 Hz & 10000 Hz?
 

JohnYang1997

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There is no weighing of any kind in any of the measurements that I posted.


Yes, the bandwidth is 20kHz.
Class D amplifier are mostly dominated by noise. So 22KBW 5W will be very different from 20KBW 10W. Probably 6-7dB difference. 8ohm vs 4ohm is another 3dB. (I think you are using 4ohm but this can happen) That's quite a lot at the state of the amplifier which is top tier. Send it to Amir and see what we got.
 

Music1969

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DonH56

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Class D amplifier are mostly dominated by noise. So 22KBW 5W will be very different from 20KBW 10W. Probably 6-7dB difference. 8ohm vs 4ohm is another 3dB. (I think you are using 4ohm but this can happen) That's quite a lot at the state of the amplifier which is top tier. Send it to Amir and see what we got.

A decrease in SNR/SINAD of 6-7 dB going from 20 kHz to 22 kHz bandwidth seems like an awful lot... That's a factor of two in voltage noise for 10% greater bandwidth. I do not know either way, just seems high.
 

JohnYang1997

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A decrease in SNR/SINAD of 6-7 dB going from 20 kHz to 22 kHz bandwidth seems like an awful lot... That's a factor of two in voltage noise for 10% greater bandwidth. I do not know either way, just seems high.
Ah right. 8ohm vs 4ohm is 6db. 5W vs 10W is 3dB. Then noise can contribute 1db or so, can be higher due to spikes or rising high frequency noise but not present here.
 
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