Come on Petr, you know this waveform is nonsense. You have connected samples with straight vertical and horizontal lines, and that is completely artificial, the signal does not look like this.
Run it through a band limiting filter or an ADC anti-aliasing filter like in the real world.
Don't try to prove something with stuff that doesn't exist.
I will give you the benefit of the doubt and assume that this is a result of your not knowing and not a deliberate misleading.
Jan
Run it through a band limiting filter or an ADC anti-aliasing filter like in the real world.
Don't try to prove something with stuff that doesn't exist.
I will give you the benefit of the doubt and assume that this is a result of your not knowing and not a deliberate misleading.
Jan
Jan, there are people in this forum using 'NOS' dacs without any output filtering (zero-order hold outputs). They produce technically improper analog audio signals such as Petr posted. Some people think it sounds good; no idea why.
Amazing the length people go to be 'different'.
Even if it totally messes up their amplifiers. 😱
Jan
Even if it totally messes up their amplifiers. 😱
Jan
Eh, nothing in this world can produce signals as posted by Petr. According to him, they all change value in the infinitely short time.
Even NOS DAC will have some RC filter between output and next stage, at least RC filtering formed by wire resistance and cable capacitance. This integrates signal and we have real word signal change speed.
To be clear, idealizing a circuit or a waveform is often used to clarify the discussion of a technical issue, and can be valuable.
However, in this case, the issue itself is caused by the idealized waveform, so that's complete nonsense.
Jan
However, in this case, the issue itself is caused by the idealized waveform, so that's complete nonsense.
Jan
"As we can see here nothing resembles a sinusoid, even its half-cycle."
Whoosh!
That went straight over your head. Missing the point that I took a deliberately simple example.
And that waveform woefully misrepresents a real signal, most likely due to far too low a sampling frequency, if, indeed, it is a "real" digitised one.
Whoosh!
That went straight over your head. Missing the point that I took a deliberately simple example.
And that waveform woefully misrepresents a real signal, most likely due to far too low a sampling frequency, if, indeed, it is a "real" digitised one.
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Jan - I agree that amplifier bandwidth in the market place is somewhat of a "faster is better" approach.
My own approach for choosing 200kHz is for a few reasons. First, it is a realistic possibility to achieve, even with 4MHz transistors, but easier with modern 30MHz devices. Secondly, it is "ten times" the audio bandwidth, which seemed to me to be an optimum target to achieve a good 20kHz response with low phase shift. Thirdly, and this is where some judgement applies, the slew rate of a higher power amplifier needs to be faster than a lower power one to maintain a similar phase response. Fourthly, I've been convinced of a more realistic sound since comparing Arthur Bailey's 30W amp with my first 2N3055 (now H, made of unobtainium) which I later found struggled beyond 10kHz, despite improving the compensation (some designs at the time being somewhat substandard, shall we say). Bailey's design pumped out a few watts at 200kHz, although the bandwidth was never explicitly stated was about 200kHz.
Lastly, in a chain of systems, all of the RC limitations add up, and I considered that keeping the power amp to a realistic minimum would minimise the cumulative impact.
I'm sure commercial designers will have different priorities.
My own approach for choosing 200kHz is for a few reasons. First, it is a realistic possibility to achieve, even with 4MHz transistors, but easier with modern 30MHz devices. Secondly, it is "ten times" the audio bandwidth, which seemed to me to be an optimum target to achieve a good 20kHz response with low phase shift. Thirdly, and this is where some judgement applies, the slew rate of a higher power amplifier needs to be faster than a lower power one to maintain a similar phase response. Fourthly, I've been convinced of a more realistic sound since comparing Arthur Bailey's 30W amp with my first 2N3055 (now H, made of unobtainium) which I later found struggled beyond 10kHz, despite improving the compensation (some designs at the time being somewhat substandard, shall we say). Bailey's design pumped out a few watts at 200kHz, although the bandwidth was never explicitly stated was about 200kHz.
Lastly, in a chain of systems, all of the RC limitations add up, and I considered that keeping the power amp to a realistic minimum would minimise the cumulative impact.
I'm sure commercial designers will have different priorities.
John I have no issue with that, as long as we agree that all the given arguments are based on personal preference only.
Which means that others' personal preferences are equally valid.
Jan
Which means that others' personal preferences are equally valid.
Jan
Jan, I have said these are my reasons. Out of curiosity, what bandwidth do you think is adequate for a hifi amp?
Correction: Let's take a fragment of a square wave signal - please note the almost infinite BW content!! .....
//
I have no specific number at the top of my head. I would have to put the arguments together, do some calculations, add a safety factor or something, then arrive at a reasoned number. Lot of work ;-)
Jan
"Which means that others' personal preferences are equally valid."
Not quite, though. Someone may have an opinion that 5kHz is OK. But it would not be valid as it is well established that the majority of people can hear up to 20kHz. 5kHz barely scraped in the old DIN45500.
Is there a new agreed standard for hifi or has it just been left for individuals and manufacturers free rein?
Not quite, though. Someone may have an opinion that 5kHz is OK. But it would not be valid as it is well established that the majority of people can hear up to 20kHz. 5kHz barely scraped in the old DIN45500.
Is there a new agreed standard for hifi or has it just been left for individuals and manufacturers free rein?
So you feel that it should be equal to the hearing limit 20k? Then why would you want 200k?
Jan
Jan
I get the impression that Petr-1951 has never tried to see a real-time signal from the output of the same sound card. What appears to be a sharp front when stretched turns out to be a very smooth slope with a low rise rate, which is not a problem for a real amplifier. Moreover, I have not listened to any dense and saturated tracks - the result is unchanged, but natural.
On the other hand, what is visually visible and sent to the sound card is one thing, and what comes out of it into the amplifier is somewhat different)
On the other hand, what is visually visible and sent to the sound card is one thing, and what comes out of it into the amplifier is somewhat different)
Hypothetical signal for virtual amplifier. Sounds awful in simulated listening test. 😀
Jan, give me a filter circuit (good according to your concepts DAC) with which the signal from the CD sounds good.
I will process and show how the sound signal will look like
p.s.
fagos, it would be better if you kept your speculations to yourself and did not flood here
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So, which one is it Petr? Do you intentionally use false signal representation in support to your ‘arguments’ or do you believe that audio signal is like that?
Now running away from amplifiers to the DAC territory. For what? To prove that their output looks just like on your graph with another flawed simulation?
Now running away from amplifiers to the DAC territory. For what? To prove that their output looks just like on your graph with another flawed simulation?
200 kHz full power bandwidth of amplifier is easy to design today.
I like more bandwidth as possible with good stability margin. Sometime I trade of the bandwidth a bit for lower distortion in high frequency.
I like more bandwidth as possible with good stability margin. Sometime I trade of the bandwidth a bit for lower distortion in high frequency.
"So you feel that it should be equal to the hearing limit 20k? Then why would you want 200k?"
Do I detect a bit if mischievousness? Answering a question with a question? 🙂
I'm sure if you re-read my post 1127 you'll see why.
To put one number on this a 200kHz amplifier will have less than 0.05dB influence on a 20kHz signal. I'm sure you knew that too.
Do I detect a bit if mischievousness? Answering a question with a question? 🙂
I'm sure if you re-read my post 1127 you'll see why.
To put one number on this a 200kHz amplifier will have less than 0.05dB influence on a 20kHz signal. I'm sure you knew that too.
No intend to be mischievous! I'm just trying to get some idea on what your opinion is based.
As I said, personal preference is OK, but I am always on the lookout for views backed up by facts and figures.
I mean, 200kHz - great. But why not 150kHz? Or maybe 225kHz?
Jan
As I said, personal preference is OK, but I am always on the lookout for views backed up by facts and figures.
I mean, 200kHz - great. But why not 150kHz? Or maybe 225kHz?
Jan