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AP reports up for schiit power amps

Dana reed

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Hemi-Demon

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Those data graphs are just so noisy. Power output looks good, but man those distortion numberso_O How can they label that "passed"
 

maxxevv

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Those data graphs are just so noisy. Power output looks good, but man those distortion numberso_O How can they label that "passed"
Completely depends on criteria set for that. It may be such a 2W output for 150 Ohm and THD+n being not part of the criteria.

I mentioned in another thread too that the headlining power output figures are impressive BUT the distortion figures are atrocious. Likewise the ditortion figures at 1khz sound fair but the AP graphs show that the 1khz mark was as good as it went, the rest of the numbers across all the frequency range were all much higher.....
 
OP
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Dana reed

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Probably passes because the spec is 0.01% at rated power, which appears to be the case. And it seems like most of the noise is mains leakage.
6F220EB9-3304-45A6-BAB1-B31BDCA75633.jpeg
 

YoloSwag

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-5-(-90) = 85, all of them are transfomer noise at 60, 120, 180, 240, 300, 360......, noise floor is pretty high too. I think 3eaudio's ti class-d amp can achieve simliar performance with much less price:facepalm:

1567737989006.png
 

maxxevv

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Probably passes because the spec is 0.01% at rated power, which appears to be the case. And it seems like most of the noise is mains leakage.
View attachment 32735

What is the rated power in the chart supposed to be ? I only see Vrms ... so what's the load there ?

Addendum:

Nevermind, I see the Vidar loading at 8 Ohms , its rated at 100W per channel.

I leave it to the experts to dissect the numbers but off hand , it should be in the -84 dB range and the 4 Ohm load version even lower at sub-80dB for its rated 200W per channel. Reasonable but nothing outstanding really when the price gets thrown into the equation.

The Hypex amps will leave it in the dust for not much more.
 
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maxxevv

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-5-(-90) = 85, all of them are transfomer noise at 60, 120, 180, 240, 300, 360......, noise floor is pretty high too. I think 3eaudio's ti class-d amp can achieve simliar performance with much less price:facepalm:

View attachment 32736

That 1Khz spur is the test tone. The rest as you noted is indeed from the mains leakage.

Which brings the question to mind, would a better made / designed transformer go some way towards alleviating that leakage ? Assuming that the rest of the circuit design isn't too badly done?
 

Sawdust123

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Actually, it could be ground noise or a pin 1 problem. Without seeing the test setup, one cannot tell.
 

solderdude

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No ... its a groundloop !


(You would have to read the TotalCRAP thread to understand the remark)
 

maty

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-5-(-90) = 85, all of them are transfomer noise at 60, 120, 180, 240, 300, 360......, noise floor is pretty high too. I think 3e audio's TI class-d amp can achieve simliar performance with much less price :facepalm:

View attachment 32736


xrk971 had measured the cheap 3e TPA3255 implementation. Of course, with very clean power to make the measurements!

Usually at home we do not have clean power (I have very dirty power, but it is a problem that I have managed to alleviate greatly :D ) at mains.

https://www.diyaudio.com/forums/gro...eference-design-class-amp-gb-post5902019.html

Optimized pictures

3e-TPA3255-test-setup-by-xrk971.jpg


3e-TPA3255-20.22vrms-8ohms-FFT-by-xrk971.png



The THD+D from the TI's PDF is much better than 3e cheap/questionable implementation.

TPA3255-THD-N.png
 
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Panelhead

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The new operating design Aegir makes the Vidar measurement look good.
The description of Aegir is confusing. Spec is a trans conductance amplifier. I thought a transconductance amp was a voltage input, current output. Usually a low voltage gain.
 
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