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Review and Measurements of Topping D10 DAC

Discussion in 'Digital Audio Converters (DACs)' started by amirm, Mar 20, 2018.

  1. Krunok

    Krunok Active Member

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    @amirm When do you think you will find time to repeat the measurements of the D10 with OPA1612 and the other op amps guys sent you? :)

    Btw, Topping just confirmed that the replaceable Op amp is doing the filtering. That means its impact on signal is not as high as those 2 op amps doing I/V conversion but it is still on the signal path, so it makes sense to measure what will happen if it is replaced with the op amp with better specs.

    Here is a nice article where different op aps have been tested acting as I/V converter and LP filtering, OPA134 (single version of OPA 2134) being one of them. According to the author, this I/V and LP circuit was meant to be at the output of the DAC in a CD player:

    https://www.by-rutgers.nl/IV-converter.html

    Keep in mind that LME 49710/49720 has come to end of life and that OPA1612 has much better specs, which explains why Topping chose it for D50 and DX7s.
     
    Last edited: Apr 16, 2018
  2. rvsixer

    rvsixer New Member

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    I am also curious, as I am looking for a inexpensive'ish decent performing USB to RCA SPDIF converter. D10 seems a better option than a Schiit Eitr (given the other Schiit measurements here).

    BTW Amirm thanks for this site and what you do for the audio community. There's simply no/few places to go for objective measurements.
     
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  3. Krunok

    Krunok Active Member

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    I was using this for a while and it worked excellent. It's based on XMOS XU208 chip and works with Singxer drivers. If you don't need D/A to be performed it should do well and it's cheaper than the devices with D/A converter.

    https://www.ebay.com/itm/XMOS-XU208...515693&hash=item1c9a5ad84f:g:A5UAAOSwmwtaKTNE
     
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  4. Zek

    Zek Member

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  5. rvsixer

    rvsixer New Member

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    Decent as in measures well. Can't find measurements anywhere...
     
  6. DonH56

    DonH56 Major Contributor Patreon Donor Technical Expert

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    Other than BER what measurements do you want to see for the converter? Unless it corrupts the data, or adds a ground loop, there will be no sonic impact.
     
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  7. Krunok

    Krunok Active Member

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    Maybe jitter at the SPDIF outputs, but I don't expect it to be high and modern DACs shouldn't really have an issue with it.

    This is an example of such measurement: http://archimago.blogspot.hr/2013/06/measurements-do-bit-perfect-digital.html
     
    Last edited: Apr 17, 2018
  8. Arnold Krueger

    Arnold Krueger Active Member

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  9. Krunok

    Krunok Active Member

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    I mentioned jitter in the context of what COULD be measured. As I said, I don't expect it to be high nor to cause problems with modern DACs. ;)
     
  10. Arnold Krueger

    Arnold Krueger Active Member

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    Not to be overly grim, but having to put his name on a jitter spec this lax could have conceivably had some effect on Julian Dunn's health.

    Science is a bitch!
     
    Last edited: Apr 17, 2018
  11. Krunok

    Krunok Active Member

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    LOOL :D
     
  12. Arnold Krueger

    Arnold Krueger Active Member

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    I have to admit that I have some technical questions about the AES3 jitter spec.

    There is a transition in audibility of FM distortion or jitter at low frequencies,. The mode of perception changes from hearing jitter sidebands subject to masking (which is the stated justification for setting AES3 where it is) and where it is heard based on the perception of an added "roughness" of low frequency tones, which is mentioned and quantified by Zwicker and Fastl's classic tome: Perception: Facts and Models.

    This is similar to the perception of changes in phase, which has a transition around 1 kHz where the ear actually starts tracking the signal wave instead of just relying on bandpass filtering. By 100 Hz and lower, our perception of phase in a free field is pretty good, but it is still rotten in typical listening rooms because room acoustics cause so much ambiguity.


    I would expect a breakpoint someplace on the far left of the graph and a different, even upward slope going down to 10 Hz and below. Bottom line, had someone actually done some crazy thing like ABX testing, they might have changed the basic AES standard.

    I suspect based on the evidence of my own ABX tests that the change in threshold would have far more impact on the vinyl and analog tape people than the digital people. They are in so much trouble and we are so golden when it comes to audible jitter. But, nobody seems to know!
     
    Last edited: Apr 17, 2018
  13. Krunok

    Krunok Active Member

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    I fully agree.
     
  14. Arnold Krueger

    Arnold Krueger Active Member

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    Executive summary of that incomplete article might be "grab the right op amp and run!" :)
     
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  15. Krunok

    Krunok Active Member

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    Hahaha - you have obviously evolved from "grumpy" to "cynic"! :)
     
  16. Krunok

    Krunok Active Member

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    [​IMG]


    I need a piece of advice from you audio op-amps gurus.. :)

    This is a block scheme of my Rotel RSP-1066 processor/preamp that I intend to use only for volume control with my D10 to come. THD and IM of the device are declared as <0.05% but it is not specified using which inputs (digital or analog) is that.

    Here are some of the additional info I have from the Rotel Service manual:

    IC301 (Zone 2 volume) : TC9459N
    IC706 (Pre out volume): TC9459F
    IC709 (Pre out tone control): TC9184P

    IC712 (and probably the rest of the op-amps) : NJM5532M

    Now, the question is if it would make sense to replace those NJM5532M with some other op-amps for better performance or is it better to leave them as they are?

    Only left channel is shown, right channel is of course the same. Operating voltage is +/- 15V.

    P.S. There is an error in the schematics - IC201 is "Zone 2" and IC203 is "Listening"
     
    Last edited: Apr 17, 2018
  17. Krunok

    Krunok Active Member

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    Additional info from specs:

    Input Sensitivity/Impedance
    Line Level: 200 mV/47 kohms

    Preamp Output Level
    1.2 V (200 mV Input)

    Now, here is the part that I don't really understand: what happens when I connect my CD player or D10, which both have 2V output, to the CD or Tape input? What happens when that signal, for example, hits IC712 with 16dB of gain? Will it make 12V on the output? :D
     
    Last edited: Apr 17, 2018
  18. Arnold Krueger

    Arnold Krueger Active Member

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    The NE 5532 is one of those old chestnuts from the early 80s that was soooo overkill then, and for line level stuff with typical low gain that does not need to be happy with flea power, it is still just fine today and needs to be left alone.

    The TC9459 is a digitally-controlled analog volume control, and other than pin-compatible replacements that *you* can research, also probably wants to be left alone.

    Op amp rolling when the device is already populated with highly adequate chips like the 5532 is a fool's mission.

    Also, depending on the vintage of the target device, there could be a lot of SMT inside, and figure on $100 or so for special tools including the hot air soldering iron and weeks of practice getting up to speed with it. And a big magnifier.
     
  19. Krunok

    Krunok Active Member

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    Well, your arguments sound very fine to me so the old guy stays as it is. Thank you Arnold! :)
     
  20. Krunok

    Krunok Active Member

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    @Arnold Krueger Can you please help me understand what happens with the 16dB gain and the output voltage when I connect 2V source (like CD player or D10) to the line input of my RSP 1066?
     
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