• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

AP reports up for schiit power amps

Dana reed

Active Member
Joined
Mar 13, 2018
Messages
244
Likes
245

Hemi-Demon

Senior Member
Joined
Jan 17, 2019
Messages
438
Likes
514
Those data graphs are just so noisy. Power output looks good, but man those distortion numberso_O How can they label that "passed"
 

maxxevv

Major Contributor
Joined
Apr 12, 2018
Messages
1,872
Likes
1,964
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
D

Dana reed

Active Member
Joined
Mar 13, 2018
Messages
244
Likes
245
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

Member
Joined
Aug 7, 2019
Messages
6
Likes
2
-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

Major Contributor
Joined
Apr 12, 2018
Messages
1,872
Likes
1,964
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.
 
Last edited:

maxxevv

Major Contributor
Joined
Apr 12, 2018
Messages
1,872
Likes
1,964
-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

Member
Joined
May 3, 2019
Messages
49
Likes
160
Actually, it could be ground noise or a pin 1 problem. Without seeing the test setup, one cannot tell.
 

solderdude

Grand Contributor
Joined
Jul 21, 2018
Messages
15,988
Likes
36,190
Location
The Neitherlands
No ... its a groundloop !


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

maty

Major Contributor
Joined
Dec 12, 2017
Messages
4,596
Likes
3,166
Location
Tarragona (Spain)
-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
 
Last edited:

Panelhead

Senior Member
Forum Donor
Joined
Apr 3, 2018
Messages
348
Likes
137
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.
 
Top Bottom