John Curl's Blowtorch preamplifier part II

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#89,181
First digital delay line install I can find reference to is 1973. One would have thought by now the OCD vinyl types would have done a complete X-ref of all analogue vs evil digital delay lines.

But hey I think the early soundstream recordings by Telarc etc sound pretty good.
 
#89,182
PMA said:
Yes Jan, in majority cases when there is a reconstruction and LP filter in the DAC. If not, like in the old days of TDA, DAC output keeps the last analog output voltage before new sample comes and you can see the staircase on scope screen. It affects spectrum and amplitude response as well.
Click to expand...

Redbook CD specifies a mandatory reconstruction filter. There is no staircase in a CD system that follows the specifications. I know there are some misguided diy systems that avoid these, but that is mostly based on misunderstanding/not knowing.

If you see staircases, your system is broken. Period.

Jan
 
#89,183
jan.didden said:
Redbook CD specifies a mandatory reconstruction filter. There is no staircase in a CD system that follows the specifications. I know there are some misguided diy systems that avoid these, but that is mostly based on misunderstanding/not knowing.

If you see staircases, your system is broken. Period.

Jan
Click to expand...

You are of course wrong in your assumption that only some DIY systems have staircase output.

Audio Note CD-4.1x CD player Measurements | Stereophile.com
 
#89,190
PMA said:
You are of course wrong in your assumption that only some DIY systems have staircase output.

Audio Note CD-4.1x CD player Measurements | Stereophile.com
Click to expand...

Well that is remarkable, a $ 12k CD player not conforming to the basic requirements for good CD replay. Or maybe they follow the principle: you need to sound different, not better.

But maybe there's another confusion here: the staircase shows the output when you leave out the mandatory reconstruction filter. But what is the connection to the non-oversampling case?

Jan
 
#89,195
For those of you interested in audibility of distortion this is an interesting starting point: QuantAsylum Home Page It gives you an easy ability to dial the distortion up and down and has several different types of distortion to explore. It is an A/B/X type of application so, of course, your ability to hear anything will be extremely suppressed with no peeking allowed.

I, for one, will be interested in the sensitivity to the different types and levels of distortion.
 
#89,196
jan.didden said:
Well that is remarkable, a $ 12k CD player not conforming to the basic requirements for good CD replay. Or maybe they follow the principle: you need to sound different, not better.

But maybe there's another confusion here: the staircase shows the output when you leave out the mandatory reconstruction filter. But what is the connection to the non-oversampling case?

Jan
Click to expand...

I'm pretty sure you're right. The last audio show I was at I heard numerous things that sounded gimmicky, as the best way to describe them. Now I haven't heard that CD player but I wouldn't mind hearing it because who knows maybe I'd like it? But mine sounds pretty darn good with great specs - I did have to modify it a little bit however.

In general I think that sounding different is a requirement that comes up because so many fail to sound good without manipulation.
 
#89,197
billshurv said:
for a larf and fresh from RMAF aqua - acoustic quality & CLONES audio | AudioStream

Its almost like a FUD focus group specified it.
Click to expand...

That's really impressive. USB Audio Class rev. 3 was released at the end of Sept. and they already support it!! (Not that anything significant changed.) It also has every buzzword in one box- R2R DAC (someone called this an "analog DAC" the essence of misnomer) DSD and vacuum tubes. With all of that it doesn't need to even work!
 
#89,198
PMA said:
I have repeated my measurements of clicks
Click to expand...

Thank you Pavel for the contribution. As always proper setup and proper documentation.
(I am eyeballing the entry level Picoscope 2000 myself).


jan.didden said:
Of course the staircase doesn't actually exist. It's just the representation on the screen. In reality only the samples are defined, and if you DA convert, it turns into a continuous wave.
Click to expand...

Jan
The content of each sample is quantized.
What comes out of the DAC and what comes out of the reconstruction filter is based on the staircase but it shouldn’t be a staircase.
The newbies won’t have a problem to understand it. The problem is with us the oldies.

George
 
#89,199
PMA, I'm sure that your measurements of the phono cartridge are OK, but this is a low end typical case, not reasonable worst case. Incidentally, the real problem, besides clicks and pops is cartridge mistracking. It is in no way as slow as what you measured: See my examples measured with analog hi speed test equipment almost 40 years ago. MY rise-time peak is 5us! (figure 7) This closely corresponds to a (TIM 30) test signal, differentiated with an inverse RIAA network or TIM(30,30) (see figure 8). Precise measurements of a phono cartridge with a 13.5KHz passive resonance and the highest tip mass that Ortofon makes is not necessarily the best representative for determinining reasonable worst case design limits.
 

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