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Review: ZERO 24 BIT/192KHz DAC/Headphone Amp/Pre-Amp
Jun 4, 2009 at 4:55 AM Post #8,941 of 9,388
Quote:

Originally Posted by Currawong /img/forum/go_quote.gif
More to the point, is there any benefit in feeding the Zero a 192k signal? The only benefit is a measuredly imperceptibly lower noise floor.


I think the benefit of upsampling is more on the final anti-imaging filter stage. Virtually every CDP/DAC nowadays upsamples. AD1852 used by Zero is a Delta-Sigma modulation DAC. The DAC chip 8x upsamples a 44.1K signal before feeding it to Delta-Sigma Modulator, in order to avoid the need for a sharp analog low-pass filter. And this is where I got confused, since the DAC itself upsamples, then why external upsampling is ever needed? DAC-1 uses AD1853 and actually upsamples everything to 110K. They claim upsampling provides '20dB filter-performance improvement'. Is it because the SRC they use better than the AD1853 internal interpolator? I don't know, but would like to experiment and see if there is actually audible differences
wink.gif
Plus, I happen to have a DVD-Audio disc w/ 192K/24bit tracks.
BTW, I can't tell the differences between the original 44.1K and the upsampled 88.2K/96K on my system. Maybe my system is not good enough
biggrin.gif
 
Jun 9, 2009 at 3:48 AM Post #8,942 of 9,388
Anyone know what is the voltage socket for zero+? also the voltage for the h/amp socket?
 
Jun 9, 2009 at 5:00 AM Post #8,943 of 9,388
The AD1852 oversamples and does not upsample. Most DACs and CDP's do not upsample.

Peete.
 
Jun 9, 2009 at 6:34 AM Post #8,944 of 9,388
Quote:

Originally Posted by Pricklely Peete /img/forum/go_quote.gif
The AD1852 oversamples and does not upsample. Most DACs and CDP's do not upsample.

Peete.


I admire you, Peete, but can't agree with you on this one. In data sheet of AD1852, 'interpolation' is used as synonyms referring the upsampling process. Oversampling does serve the same purpose, but it has to happen at the ADC stage. Since tracks on CD have a fixed sampling rate of 44.1K, how can you oversample already sampled signals? Besides AD1852/53, both CS43XX and AK43XX use similar 8x interpolators internally.
 
Jun 9, 2009 at 7:04 AM Post #8,945 of 9,388
Quote:

Originally Posted by x_lk /img/forum/go_quote.gif
I admire you, Peete, but can't agree with you on this one. In data sheet of AD1852, 'interpolation' is used as synonyms referring the upsampling process. Oversampling does serve the same purpose, but it has to happen at the ADC stage. Since tracks on CD have a fixed sampling rate of 44.1K, how can you oversample already sampled signals? Besides AD1852/53, both CS43XX and AK43XX use similar 8x interpolators internally.


I think we're getting bogged down in badly understood terminology.

Upsampling vs. Oversampling

Lavry Engineering: Sampling
 
Jun 10, 2009 at 5:59 PM Post #8,946 of 9,388
Hey there.

Do you think it's ok to place the zero on it's side, kind of like the way the dac magic can? (I've got space constraints) I would build some kind of base for it, like the dac magic. & if it's ok, which way up do you think it should go, ie, headphone jack near the top or the bottom? (I haven't done any mods to it, so nothing's flapping around in there (hopefully!))

Thanks. By the way, mine's been working fine since day 1 (bought from wsz last year some time)...just a little bit of hum that you have to get close to to hear.
 
Jun 10, 2009 at 7:18 PM Post #8,947 of 9,388
Thanks for the links Dro !!

I think that settles the differences rather plainly.

Peete.
 
Jun 10, 2009 at 9:43 PM Post #8,948 of 9,388
Going back and forth on the Zero and my friend's Theta DS Pro prime, and the Zero (w/ the OPA-Earth in it) is definitely sounding harsher than the Theta. The Theta in comparison is smooth and flowing, while the Zero has an edge to the music. I'm guessing the OPA-Moon would help out in that regard? The Sun was murder on the ears with the MS-2is, so I'm leaving it far far away from the Zero.
 
Jun 10, 2009 at 10:20 PM Post #8,949 of 9,388
Quote:

Originally Posted by azncookiecutter /img/forum/go_quote.gif
Going back and forth on the Zero and my friend's Theta DS Pro prime, and the Zero (w/ the OPA-Earth in it) is definitely sounding harsher than the Theta. The Theta in comparison is smooth and flowing, while the Zero has an edge to the music. I'm guessing the OPA-Moon would help out in that regard? The Sun was murder on the ears with the MS-2is, so I'm leaving it far far away from the Zero.


Would be interesting to hear the Theta up against the Audio-GD REF1, that would be fun!

.
 
Jun 11, 2009 at 12:53 AM Post #8,950 of 9,388
This is a random question, but does anyone know if while the unit is set in Preamp mode, if it bypasses the amplifier circuit?
 
Jun 11, 2009 at 4:49 AM Post #8,951 of 9,388
Quote:

Originally Posted by les_garten /img/forum/go_quote.gif
Would be interesting to hear the Theta up against the Audio-GD REF1, that would be fun!

.


Thing is, the Theta mates especially well with the MS-2is. Almost a magical match, especially with the Millet Hybrid in the audio chain. Would be interesting to see how the Moon stacks up, especially with the fact that it's more rounded off, and not as sharp as the Earth.
 
Jun 11, 2009 at 5:25 AM Post #8,952 of 9,388
Quote:

Originally Posted by azncookiecutter /img/forum/go_quote.gif
Thing is, the Theta mates especially well with the MS-2is. Almost a magical match, especially with the Millet Hybrid in the audio chain. Would be interesting to see how the Moon stacks up, especially with the fact that it's more rounded off, and not as sharp as the Earth.


Even with Grados, I'm not much of a Moon fan. Kinda dull sounding to me.

.
 
Jun 13, 2009 at 2:46 PM Post #8,953 of 9,388
Quote:

Originally Posted by brady7 /img/forum/go_quote.gif
Hey there.

Do you think it's ok to place the zero on it's side, kind of like the way the dac magic can? (I've got space constraints) I would build some kind of base for it, like the dac magic. & if it's ok, which way up do you think it should go, ie, headphone jack near the top or the bottom? (I haven't done any mods to it, so nothing's flapping around in there (hopefully!))

Thanks. By the way, mine's been working fine since day 1 (bought from wsz last year some time)...just a little bit of hum that you have to get close to to hear.


bump, hopefully someone who's poked around inside this thing sees this.

Thanks
 
Jun 13, 2009 at 3:09 PM Post #8,954 of 9,388
Quote:

Originally Posted by brady7 /img/forum/go_quote.gif
bump, hopefully someone who's poked around inside this thing sees this.

Thanks



Won't hurt it on it's side except for a few things;

1) Make sure there is ample ventilation around the case
2) Orient it with the Vents at the highest point, ie the headphone Jack at the top so heat can get out of the headamp
3) If you have an HDAM, open it up and make sure it is double sticked well or it may come loose.

If you don't know what an HDAM is, you probably don't have one.

.
 
Jun 16, 2009 at 12:57 AM Post #8,955 of 9,388
Quote:

Originally Posted by les_garten /img/forum/go_quote.gif
Won't hurt it on it's side except for a few things;

1) Make sure there is ample ventilation around the case
2) Orient it with the Vents at the highest point, ie the headphone Jack at the top so heat can get out of the headamp
3) If you have an HDAM, open it up and make sure it is double sticked well or it may come loose.

If you don't know what an HDAM is, you probably don't have one.

.


Thanks, will do. Right, it's one of the earlier models (no HDAM)...I ordered the zerodac after getting about halfway through this thread, then read the rest later & found out you'd all moved on to the HDAMs!
 
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