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Review and Measurements of Pro-Ject Pre Box S2 Digital

DonH56

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#81
:D Some Watkins-Johnson guys snuck it into an old datasheet. National Semi was another company famous for inserting a gag datasheet or two in their databooks.
 

Music1969

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#82
So as you see the filter choice is invariant in this equation.

But this does show some extreme issues with Optimal transient and to much smaller extent the min phase modes.
From here:

"The Audio Quality menu has two options, "Best" and "Test".

"Best" is the way it sounds best to John: Distortion Compensation is disabled and the filter is Optimal Transient.

"Test" is the way John's test instruments like it: Distortion Compensation is enabled and the filter is Brickwall. You can also go into the menus to individually adjust those however you'd like including several other filter options, after which Audio Quality will display "User".


This is why I thought perhaps the filters are actually involved - in this case, you've found a potential issue with optimal transient.

Thanks for the additional measurements. They've isolated optimal transient filter, at least.

And your results now shows more clearly (to me) the distortion compensation effects, against all filters - interesting that it shows some small differences in absolute values, very slightly worse with the feature enabled.
 

Music1969

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#83
Also Amir, I don't know if you have the ability to do PCM up-sampling (via Roon) to 768kHz, to see if you by-pass the DAC's internal digital filters, does distortion reduce?

This is what Jussi's measurements show on the CA Forum thread.

Roon's PCM up-sampling, even to 768kHz, is fortunately not that CPU intensive, compared with DSD up-sampling.
 

Jimster480

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#84
No as I am keen on having one for future testing. That said, when I asked to buy Topping DX7s, they offered to send one to me without charge. So maybe they do the same. :)

BTW, they just contacted me back asking me where I am so that they can refer me to local people. Let's see what comes out of it.
Who is the "they" you are referring to here? Do you mean Topping/TPDZ?
If so, I know that so far in dealing with them they have been very transparent and straight forward even when it isn't to their advantage.
 

Jimster480

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#85
With all due respect to Topping, but they can't price themselves at the same level as well established audio manufactures, even if their products are the same or better.
Personally I think they can justify the price if their goods are matching in quality. Maybe right now some people are skeptical, but I wrote a nice review of the A30 (subjective ofc) almost a year ago and the D30/A30 stack became quite popular after that. Going on massdrop quite a few times aswell with many units ordered. I didn't intend for any specific outcome, I just shared my thoughts because when I bought the A30 nobody that I could find had one and there were no reviews on headfi or any other forum I Could find.

So now that the DX7 has proven itself, as the D30 has aswell I think that after the DX7S measurements are in and there are some more units tested with similar great reviews they will establish their worth quickly. Especially with their transparency, customer support and hard work at delivering on their promises (atleast so far it seems).
 

sonci

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#86
Personally I think they can justify the price if their goods are matching in quality. Maybe right now some people are skeptical, but I wrote a nice review of the A30 (subjective ofc) almost a year ago and the D30/A30 stack became quite popular after that. Going on massdrop quite a few times aswell with many units ordered. I didn't intend for any specific outcome, I just shared my thoughts because when I bought the A30 nobody that I could find had one and there were no reviews on headfi or any other forum I Could find.

So now that the DX7 has proven itself, as the D30 has aswell I think that after the DX7S measurements are in and there are some more units tested with similar great reviews they will establish their worth quickly. Especially with their transparency, customer support and hard work at delivering on their promises (atleast so far it seems).
I still think they will make a lot more money keeping their prices low.
More people will try, and hear that there's not much difference comparing to big bucks audiophile names.
If I have already a high end dac, I could buy D30 just for trying, but I cannot justify buying another expensive Noname Dac, that it will be hard to sell..
 

Jimster480

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#87
I still think they will make a lot more money keeping their prices low.
More people will try, and hear that there's not much difference comparing to big bucks audiophile names.
If I have already a high end dac, I could buy D30 just for trying, but I cannot justify buying another expensive Noname Dac, that it will be hard to sell..
Well remember they are testing every device on the analyzer before they send it... That isn't cheap as it adds alot to production time.
They aren't trying to be a cheap no name brand or they wouldn't be chasing the high end with something like the DX7...
Also if you had bought a DX7, then selling it wouldn't be hard.
Actually selling a D30 or A30 wouldn't be too hard either....

I mean when I went to sell my modi multibit it took some weeks, and my Fulla 2 never sold after many months...

My denon D7200 didn't sell easily either.
So it's really about what is in demand.
 

amirm

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#91
We don't have any AKM chip measurements yet, then :) ?
I am pretty sure we have tested some. I just don't keep track of them. :)

What are some of the most popular DACs that use AKM parts?
 

drconopoima

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#92
I am pretty sure we have tested some. I just don't keep track of them. :)

What are some of the most popular DACs that use AKM parts?
From the ones that you've measured

  • Schiit Modi 2
  • JDS Labs OL DAC

Other:
  • Schiit Bifrost (not the multibit)

A DAC that you have bought I think:
  • SMSL m8a

And it's also in the SMSL Sanskrit Pro-B.
 

RayDunzl

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#94
I am pretty sure we have tested some. I just don't keep track of them.
If you are going to test Velvet Sound you'll have to include The Velvet Fog in any listening tests.
 

amirm

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#95
From the ones that you've measured

  • Schiit Modi 2
  • JDS Labs OL DAC

Other:
  • Schiit Bifrost (not the multibit)

A DAC that you have bought I think:
  • SMSL m8a

And it's also in the SMSL Sanskrit Pro-B.
Thanks a bunch. Please stay on top of me to document this in my future reviews. :)
 
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