For example: the TDA 1543 invert the phase as well as a TDA1541 . That was made from project I believe since Philips would always engage an OP amp in the place of the I/V converter wich would invert the phase itself (for amplification topology reasons ) .So in that case I know where the chain inverts . The case of TDA1543 and 1541 with OP amp I/V conversion would be 2 times phase invertion .

But lets say I build a balanced dac out of a I2S signal ... and I know where it inverts ....  I would have 2 polarity signals ... right?

Maybe I am missing something here about the difference between Polarity and Phase .

Stefano

Better out of PA for now , yes . IF it is also a crack and not only a plop it is to be considered a bit demaging in my view .

I am building amplifiers from ten years now , and somehow I do know a bit of them . But also your dacs may be at risk .

So , being it a crack or not it is to be understood that is not only DC . That fenomenal generates a spread of frequencies up to 40KHZ , which can also be bad karma for your Tweeters .


Below find the picture of the spectrum plot referred to the previous (simulation Peter ? ) example posted by me .
The analysis of the spectrum is made just when the thing happens , during the drifting .

Stefano
Stefano

So from the above I should read that if Arc Prediction is engaged but the reproduction is set to say 32 bit and 44100Hz PA is out of Arc Prediction anyway ...

stefano

no there isn't a reverse effect , but just a conga playing in the music just when the stopping  sequence commence ( PE/AP) .

So what I did call " first loop " effectlively will be repeated after  one time ( second loop ) and a third time just in part .

S

no prob Peter

I did noticed this morning , that into Anti Image filtering there wasnt sample repeats and other things for the first time , but ... it was late .. late and more over engine3 would crash in that situation ( ... ) .

Well . Not bad for now

:-)

stefano

Hi All ,

I did some work around this PLOP at Stop issue .
Since I did read a lot of things about amplifiers and such ( some of them rather displeasing ) , I want to put a couple of pictures that hopefully will clarify a bit what is happening at the stop (or when we push the stop button in XXHE) of the song with PA working . Notice that the following pictures do show a *good* case when the bad cracks are not happening . What we see , are some loops ( I think many people here know that already ) and the stop itself , that we *perceive* as a bad plop .

Set UP : In this test I didn't use a real DAC at all . Infact I did use the Virtual Cable ( which can be configuarble up to 16X sampling frequency/32 bit operation and for KS) .
Then I just recorded the sound directly from the software via windows . So: no real USB to I2S is involved , no real USB DAC is involved .

Then what we see in the little sample representation is 2 channels of the stereo song playing at around -30db , then we see the samples repeated at the end when Stop is Pushed in XXHE .

Again , I did this to have an idea of what is going on . But I think is close to what happens in our USB DAC setup .

In the first figure we see the meter ( in ROSE color evidence) and the song position triangle ( in ROSE color evidence) during playing music .

In the second figure we see the meter ( in RED color evidence) and the song position triangle ( in RED color evidence )just about at the end of the whole thing.

What I do note , is that *during* the 2 sample repeats , the level of the sample drifts from 0 with respect to its "symmetry" . The METER of the player ( or editor ) shows incresing volume ( (see the RED Evidence ) but of course we do not hear this increase at that moment ) that then stops as a form of plop .

I have the recordings made at 88200 , and of course the plop is there as a reproduction for every player , and yes it is audible just the same .

stefano

PS : volume in XXHE was set at -9 db . PH - and strenght 0
      PE + Arc Predict (2X).

i was just wondering last night if shadow copies are ON in minimized os. I feel like the next thing to do will be to have a tool to restore w7 outside/extra windows ,and leave the os disk definitely Not PROTECTED. Also i am learning to not take for granted the speaker icon as a minimized advisory. In my set up minimized apply ,but xx wont shut off wasapi. Stefano

Hi all , I am AMAZED seeing what that software DriverMax has done in my laptop vista . Amazed .

 

Thank you !

Great !! it worked .

Computer>properties>remote settings

I needed to disable audio for the XXHE Time Resolution .


S

No prob , I am not taking any offense .

;-)

Sounds good to me 

well probably this is off topic , and I pass this . But , what have to do dc coupling or blocking or the woofer being capable of the 5Hz response with the PA feature ?


Stefano

And what if the cap lets your amps response down to say 5Hz? Why do you think the only danger is pure DC ?
Again we must see capacitors as DC coupling ( and filters ) for some reasons of schematic and topologies , not only to block dc and let music play .


Stefano

Well maybe that is telling us the GC is not good without the input being DC cap Coupled ....and maybe the enourmous gain of it looks toward wild instability if the input sees some of the source changes .... .
The output cap is another story .

stefano

Interesting to see that the much maligned capacitor is playing a role again , in a place where at least a couple of things are assumed not so correctly
For example . It is incorrect to say that any amplifier blocks dc , aswell as calling capacitors Blocking DC .
Capacitors do Couple for DC .
 
b- a gain clone chip which has I believe at least 60 db (90db?) open loop gain , and some 30 or 40 db of gain is going to waste by the feedback loop and is it comparable to the distorsion of a capacitor ... I mean in Music?

c- we are talking a bit of the PA feature of XXHE , that *for now* can be far more offensive than the vaste majority of capacitors on the planet .
Offensive for its inherent problems ( for now - for someone .... ) about plops at start , or at stop putting up volume over the +zone in db.

and more : AP is not about L and R phase somewhere I did read ( if right of course) and now suddenly and with reason it is ok to predict that the dc offset of the amps should have same values to every channels , for those concerned about the maybe not neglectable 300mV .
.

Maybe I am missing the point .
When and why is it safe to use PA in XXHE judging with the Voltmeter?

Is it really DC ,something that let your woofer excurs for a centimeter when music Stops ? What can capacitors really do about that?


Stefano