Hi-Rez SACD
Hi Werner,
When my friend demonstrated his very expensive Sony SCD-1 SACD player I was pretty disappointed in the new format.
So we chatted a lot on what we are going to do about it.
Eventually we decided to order the Allen Wright mod. Allen bypasses all the opamps in the analog domain and the "current-pulse" converter, whatever that is, after the DAC. Allen also provided two clocks as part of the mod: a Tent clock and an LCaudio XO-2. Of course I also threw in my own clock. For me this was an interesting experience comparing clocks in a top of the line SACD player.
To make a long story short: my friend does not like the Allen Wright mod but I do! And my clock is still in his player.
So what I intended to say was not to abandon hi-rez but make the best of it. SACD has more dynamics, vastly improved definition, depth and imaging, more extended highs than the CD. However my CD sounds more "romantic". This maybe also an effect of the DAC used. I also heard on my system a Marantz SACD that sounded friendlier, almost too, but lacked slam and authority.
Hi Werner,
When my friend demonstrated his very expensive Sony SCD-1 SACD player I was pretty disappointed in the new format.
So we chatted a lot on what we are going to do about it.
Eventually we decided to order the Allen Wright mod. Allen bypasses all the opamps in the analog domain and the "current-pulse" converter, whatever that is, after the DAC. Allen also provided two clocks as part of the mod: a Tent clock and an LCaudio XO-2. Of course I also threw in my own clock. For me this was an interesting experience comparing clocks in a top of the line SACD player.
To make a long story short: my friend does not like the Allen Wright mod but I do! And my clock is still in his player.
So what I intended to say was not to abandon hi-rez but make the best of it. SACD has more dynamics, vastly improved definition, depth and imaging, more extended highs than the CD. However my CD sounds more "romantic". This maybe also an effect of the DAC used. I also heard on my system a Marantz SACD that sounded friendlier, almost too, but lacked slam and authority.
The linear phase filter 1
From TI AB-026A:
“The filter characteristic most desirable for sensitive DSP type applications is linear-phase. The linear-phase filter is sometimes called a Bessel (or Thomson) filter. The linear phase filter has constant group delay. This means that the phase of the filter changes linearly with frequency, or that the group delay is constant. These filters maintain phase information for sensitive DSP applications such as correlation, and preserve transient response. These characteristics are critical in audio applications as well, because they affect sound quality greatly.
FIGURE 1. Passive Third Order, Linear-Phase, Low-Pass Filter Prototype”
From TI AB-026A:
“The filter characteristic most desirable for sensitive DSP type applications is linear-phase. The linear-phase filter is sometimes called a Bessel (or Thomson) filter. The linear phase filter has constant group delay. This means that the phase of the filter changes linearly with frequency, or that the group delay is constant. These filters maintain phase information for sensitive DSP applications such as correlation, and preserve transient response. These characteristics are critical in audio applications as well, because they affect sound quality greatly.
FIGURE 1. Passive Third Order, Linear-Phase, Low-Pass Filter Prototype”
Attachments
The linear phase filter 3
OK, later they wrote in AB-026A:
“The passive design shown in Figure 1 is neither a Butterworth nor a Bessel response; it is
something in between. The component values for this particular response, optimized for phase linearity and stopband attenuation, were found through exhaustive computer simulations and empirical analysis.”
Then they derived active circuit based on the Generalized Immittance Converter. The measured phase response of the active filter is shown below.
How they got this figure? It is not correspond to simulations at all.
Can somebody check the handbook for T L-C-L Bessel filter component values?
OK, later they wrote in AB-026A:
“The passive design shown in Figure 1 is neither a Butterworth nor a Bessel response; it is
something in between. The component values for this particular response, optimized for phase linearity and stopband attenuation, were found through exhaustive computer simulations and empirical analysis.”
Then they derived active circuit based on the Generalized Immittance Converter. The measured phase response of the active filter is shown below.
How they got this figure? It is not correspond to simulations at all.
Can somebody check the handbook for T L-C-L Bessel filter component values?
Attachments
Jocko Homo said:
It sounds right in my system and...
I made several NOS Dacs with TDA1541A and TDA1543.
On my main system I have now my Philips CD650 with TDA1541A NOS Dac.
I have managed to put a TDA1543 NOS Dac, complete with transformer/PSU inside my Marantz CD52SE.
I took my Marantz to several people's homes (some of them with expen$ive systems) and I always have much difficulty in bringing my Marantz back home.
Simply because people's reactions is that they've never heard CD sounding as good as this.
So... it sounds very good on ALL the systems I've tested.
Now I've got to challenge a friend of mine and do an A/B test with the Linn CD12.
BTW, these two CDPs have Tent clocks.
I just stumbled across this old post and just wanted to mention that one such DAC exists, and I actually now have it in my system:
RATOC RAL-24192DM1
(dual mono using two PCM1704 chips, no oversampling and no digital filter)
I measured its frequency response when reproducing 24/96 material, and it's -1dB @ 20 kHz. With 16/44.1 files, instead, it's almost -6dB at 20 kHz (see attachments).
It sounds good with high-res, but a bit dull with redbook, IMHO.
Marco
Attachments
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