Some measurement of commercial class D

[banana]

Banana, it is obvious from your THD vs Frequency plots that you have a 20kHz filter set on the AP. Either that or this amplifier has some serious roll off at higher frequencies. You should really be testing with the AP AUX-0025 Class D measurement filter. Here is a link.

-SL

Yes, 20KHz filter was used, but not A-weighting. That's also what chip manufacturer did when making the dataheet.

Thanks for the link.

 

[Pano]

Hey Banana!
I don't know how I missed this thread until now.

Your measuremnts of the Super-T look very much like mine: Good to have 2 independant sets of measurements.

I'm interested in seeing more. Keep up the good work!

Here is a link to my other measurements.

 

[Solve]

panomaniac:from your site
"The amp has the typical rising response on the top end with loads greater than ~6 ohms."
So if i have speakers with 4 ohms, or lower, it's not so hard on the top?
Sorry for stupid questions...

Solve

 

[classd4sure]

Correct. However it also tells you it's not a flat load independant frequency response...

 

[Solve]

And it sounds?

More stupid questions...

🙂

Solve

 

[Solve]

I mean...
"flat load independant frequency response"
Learn us!
I dont know what that means?

🙂

Solve

 

[koolkid731]

"flat load independant frequency response" is not quite correct English, which is not subject of the forum.

"flat load-independent frequency response" means the FR is flat and is independent of load, such as 4-ohm or 8-ohm or no load. FR can be load-independent without being flat. Of course flatness is limited to some frequency beyond which FR will go down pretty fast - and sometimes goes up to a peak before going down, similar to the FR of an undamped LC filter, when there's no load. That is typically the case of classD amp without post-filter feedback.

 

[Solve]

Still no understand so much.
I understand, and respect -diyaudio.com-
But cant you help us idiots and make it simple?

I play git since i was 15.
Next year im 50...
Damn!
If i have to play music...

Lots of tube!
Cant think of anything other!
Have an old Selmer.
http://www.vintagehofner.co.uk/gallery/gallery3/sel3.html
And SURE i can hear diferences when i changed the preamp
stages ECC83.
And the EL 34 at the bottom.



I play and hear.

But in it this im lost... in something i cant understand.

I love T-amp and Tripath.

But i want to learn more!

🙂

Solve

Make it esay.

 

[banana]

Hi Solve,

In audiophile terms it's called "poor damping factor", especially in high frequency.

 

[Solve]

"poor damping factor"
Im still stupid, i know its hard to explain but
how those it change in omhs?
Now have 1502 people looked at this topic.
Im and sure that 1600 have looked before i answered...

Im stupid on this.
Learn me.

An DIY forum have to be introvert!
But ...

🙂

Solve

 

[classd4sure]

"poor damping factor"
Im still stupid, i know its hard to explain but
how those it change in omhs?
Now have 1502 people looked at this topic.
Im and sure that 1600 have looked before i answered...

Im stupid on this.
Learn me.

An DIY forum have to be introvert!
But ...

🙂

Solve

C'mon solve, you know what they say in law enforcement, ignorance is no excuse?

You can't really expect people to fully educate you here. Google is your friend. We can help fill in the blanks. Don't be lazy.

 

[Solve]

Yes i know...
And accept.
🙂
Just talking and trying to understand something i want to understand and dont...

🙂

Solve

 

[classd4sure]

I can't really recommend a good one offhand, but at that base level, a good book can really help boost you ahead.

 

[Lars Clausen]

Good Job Banana. I can only encourage you to test as many different amplifiers from the market as possible.