Petr I have to apologize for giving wrong information: I said 'a $ 100 sound card ...'. I just looked it up and the sound card used for the attached measurement costs € 105, that's almost $ 115!
BTW Where are your Hafler measurements? Would be nice to compare. If you have some time while trying to find another cut-and-paste fragment on the internet to change the subject.
Ohh, and I forgot, you don't know REW: it is not only to measure HD, all kind of spectrum representations, any time domain measurement, freq response, phase response, Group Delay, single tone, burst, multitone.
And of course all matter of acoustic measurements. And if you need something that isn't in it yet, John M will quickly put it in.
Of course it is free, what were you thinking?
To be honest, this system gets very close to my AP 2722 for -40dB of the price!
Jan
BTW Where are your Hafler measurements? Would be nice to compare. If you have some time while trying to find another cut-and-paste fragment on the internet to change the subject.
Ohh, and I forgot, you don't know REW: it is not only to measure HD, all kind of spectrum representations, any time domain measurement, freq response, phase response, Group Delay, single tone, burst, multitone.
And of course all matter of acoustic measurements. And if you need something that isn't in it yet, John M will quickly put it in.
Of course it is free, what were you thinking?
To be honest, this system gets very close to my AP 2722 for -40dB of the price!
Jan
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+1, strong point of sound card is versatility (weak point is calibration and interfacing, need attenuators etc) ; the excellently specified Virtins does it, even Ap saw the light and added an ASIO mode so their gear can act as a soundcard with user's choice of software, heck even Quantasylum did.
I wonder if someone did a listening test on APx555 as a soundcard 😀
Here's a challenge for petr:
Design a test signal to measure First Cycle Distortion with a soundcard. 192ksps, so you get 96kHz bandwidth to play with. This includes the extraction algo to pull the data out of the recorded waveform, of course.
I wonder if someone did a listening test on APx555 as a soundcard 😀
Here's a challenge for petr:
Design a test signal to measure First Cycle Distortion with a soundcard. 192ksps, so you get 96kHz bandwidth to play with. This includes the extraction algo to pull the data out of the recorded waveform, of course.
But you say "Basically, these are speed distortions that depend on tPD".
Do you claim that tPD is not constant?
/örjan
There are no more 'velocity distortions' starting at the 2nd period, this is ONLY valid for amplifier bandwidth significantly higher than de signal frequency. So you can't say that as a general rule.
This is connected to the rise time or overshoot on a square wave. You can have the situation that the square wave response hasn't returned to steady state yet by the start of the next polarity period.
Jan
This is connected to the rise time or overshoot on a square wave. You can have the situation that the square wave response hasn't returned to steady state yet by the start of the next polarity period.
Jan
Agree. My point was that this system, which is not perfect as you say, is still orders of magnitude better than the old tired Hafler test. No competition.
And yes, I have listened to an APx555 acting as a DAC when I was visiting SY last time. Sounded pretty nice to me ;-)
Jan
Do you use a real oscilloscope or in the simulation?
I don't think the small wiggle before/after the wave form really happens. It is due to the limited bandwidth of the oscilloscope. At the corner of wave form starting/ending, there are infinity frequency components. However, there is limited bandwidth in FFT algorism.
I guess that you will not see the wiggle when you use analog oscilloscope.
PS: "Wiggles" also happens in the simulation, if the software chooses "time step" not small enough.
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You will get the wiggles. If you create a signal with a few cycles of sinewave in the middle and all the rest filled with zeros, then this is only a digital representation of an actual signal, which has limited bandwidth, therefore it cannot have a perfectly sharp corner. When the soundcard plays it, it is upsampled to whatever frequency the DAC uses internally. If it uses a sinc filter, you will get the wiggles. If it uses some other form of filter they may be phase shifted after the rising edge, and you will get a rounded corner.
I guess you are right. It may happen in DAC, also ADC.
However, I don't think an amplifier will introduce this error.
No, it is not in the analog input signal, it is caused by the sampling process.
Jan
Jan
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To refute the position you have taken, you first need to fix it and start to understand it consistently, refuting the theses and erroneous statements included in it. But you are spinning like a weather vane on the roof and at the slightest attempt to start a scientific discussion, you change the topic or the model on which the analysis is carried out. Yes, you are right, in such conditions it is impossible to refute your words correctly and unambiguously.
You continue to refer to authorities, although even this you do with mistakes. From the list of manufacturers you have given, Threshold and Krell use negative feedback and do not disdain. And so in almost every statement you make, there are errors and inaccuracies, unverified information, references to authorities, etc. So yes, the flag is in my hands. At least it's real for me, and not Korean, like yours.
When communicating through a translator, it is better to use a service from yandex, not from google. There is no policy or advertising, just a comparison of the quality of translations is not in favor of the latter. And sometimes your posts are full of surprises for our foreign colleagues and I'm surprised that they still understand you. I can't say that there are no mistakes in mine, but I try to read and check the translated text as far as my poor knowledge of English allows.
Petr,
When you have confidence in the table you published in posting #632, why then are you still wasting your time on solid state amps.
According to this table tube amps are far superior in perceived sound reproduction.
It would be still interesting to get a link or a copy of this article.
Hans
When you have confidence in the table you published in posting #632, why then are you still wasting your time on solid state amps.
According to this table tube amps are far superior in perceived sound reproduction.
It would be still interesting to get a link or a copy of this article.
Hans
Jan, when calculating, I use at least 1000 samples per signal period. How many samples does the sound card take for a 20 kHz signal? Even if we take the spectrum only up to 80 kHz, how many samples will it take to calculate the 4 harmonic of the signal? Therefore, do not make me laugh (my slippers) with your laboratories on sound cards.
orjan, I repeat again: velocity distortions occur mainly at the very beginning of the first period, as well as with changes in frequency and amplitude, even with an ideally constant GDT. This is why there is a big difference between tests using noise-like signals (pink noise) and multi-tone tests.
of course, we are talking about the first period of the sinusoidal signal.
fagos, your flood has already got me, don't you think you're acting mean?
orjan, I repeat again: velocity distortions occur mainly at the very beginning of the first period, as well as with changes in frequency and amplitude, even with an ideally constant GDT. This is why there is a big difference between tests using noise-like signals (pink noise) and multi-tone tests.
of course, we are talking about the first period of the sinusoidal signal.
fagos, your flood has already got me, don't you think you're acting mean?
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So Petr, which equipment do you then use to get 1000 samples at 20kHz? That sounds very interesting.
My best sound card has up to 768kHz sample rate. My AP SYS 2722 goes up to 262kHz for the wideband ADC.
So I am very curious about your super duper equipment!
Jan
My best sound card has up to 768kHz sample rate. My AP SYS 2722 goes up to 262kHz for the wideband ADC.
So I am very curious about your super duper equipment!
Jan
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It is possible to measure phase shift to the picosecond with a soundcard. I've done it before, it is not complicated for anyone who understands the basics of sampling and signal processing.
Now, please post the link to the article with the noise intermodulation test, the one where the tube amp got a high score. That's interesting.
Now, please post the link to the article with the noise intermodulation test, the one where the tube amp got a high score. That's interesting.
My 16 bit Picoscope samples at 1Gs/sec.
So let Petr tell me what signal to sample in a real test setup and what to measure.
I’ll do it within hours after having received the full and exact instructions.
Hans