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Thoughts on a bunch of DACs (and why delta-sigma kinda sucks, just to get you to think about stuff)

Discussion in 'Dedicated Source Components' started by purrin, Dec 5, 2013.
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  1. blasjw

    Also possible.  Many vintage DACs have all four digital chips socketed i.e. the two DACs, digital filter, and input receiver.  For example, you can buy a kit with all four on eBay for a Parasound DAC 1000 to go from PCM63 to PCM1704 with full 96/24 support (see link below).  I just finished socketing all four chips on my GDA-600 yesterday so I may try rolling PCM1704s myself at some point.  Maybe after I try some PCM63-K2s or -Ys.  [​IMG]  Now, I'm just waiting for the opa627s to burn-in (I socketed the opamps as well).  [​IMG]
  2. DreamKing
    I see, but then you can say (from a quick glance) the PCM63 is a downgrade in SNR (despite A-weighting on the 63) and in DR from the 1704.
    https://secure.aes.org/forum/pubs/journal/?ID=2. It's been researched through and through. Cite what shows that a particular measurement at this level isn't transparent audibly.
  3. Jones Bob
    Anything is possible. I've seen a 440ci Mopar in a Karmann Ghia.
     I forgot what digital filter was in my old GDA600, probably was not a BB DF1700 as that was released later. Good luck with using that kit on a GDA600. You will learn ALOT. [​IMG]
    HemiSam likes this.
  4. DreamKing
    That certainly doesn't sound very pleasing to me..I'll do what I can to try both the 63 and 1704 at some point though, to get a better idea.
  5. DreamKing

    What a waste of time and dough then. I'll keep note of never taking up a self-performed dac upgrade. Has there ever been a case where it was effective (meaning with other chips)?
    Never mind, just saw blasjw's 1000 post about the Parasound DAC 1000.
  6. blasjw
    Actually it is DF1700.  Below are the chips.  CS8414 is pin-for-pin compatible with CS8412 BTW.  I'm always down for learning something new.  [​IMG]
    2 x Burr Brown PCM63 (20-bit). 
    1 x Burr Brown DF1700 digital filter.
    1 x CS8412  digital receiver.
  7. Unless I'm doing absolutely critical listening, sitting there concentrating on nothing else, am I really going to notice a difference in dacs on the lower end? 
    I'm considering music streamer II to music streamer HD right now. 
  8. Ableza
    In my opinion, you'll only notice issues.  So if one is noisy or has bad distortion then yes, you'll notice.  Otherwise... not so much.
  9. jacal01
    What I noticed with the M7 was a buzz or fuzz out at the very low bass frequencies with performance enhancing headphones, such as the TH900s.  I had thought at the time that it was a downside of the enhancing property of the headphones coloring, but that bass bottom looseness has never been duplicated using the Yggy inline with the TH900s.  The Yggy is somewhat brighter and sharper in attack in comparison with the M7, tho.
    ciphercomplete and HemiSam like this.
  10. Argo Duck
    ^ Wait! I can enhance my performance with headphones? TH900s?? Ordered! :p
  11. jacal01
    You caught that particular euphemistic buzz phrase, did you?  I was grinning while I wrote it.
    But yeah, non-consumable and everything...
  12. Jones Bob

    With the DF7000 stock in the Adcom, looks like you are close to actually being able to swap out the guts of your GDA600. If you do it, please post an update here.

    BTW, even though they share the same pin out, it will need an adapter for the CS8414. It's a SOIC and the CS8412 is a DIP.
  13. Sapientiam
    Yes, you can certainly cite some measurements which PCM1704 beats PCM63 on, but you didn't ask about those.
    As for Meyer and Moran, its a joke. But discussing its various flaws will land us in 'Sound science'. For a more carefully researched paper you could search for Belcher's work at the BBC in the 1970s, he wrote an article in 'Wireless World' titled 'A new amplifier measurement' which showed no correlation between THD and SQ in amplifiers.
  14. DreamKing
    I asked for waysplural, that you somehow reduced to a singular measurement you and I agree doesn't matter:
    Meaning as a whole dac chip to another dac chip, is the 1704 a downgrade.
    And as for Meyer and Moran, either way I don't care what research paper you like or don't like as long as we agree that measurements aren't conclusive to audible differences in almost any case. Especially not at the PCM63 and 1704 level.
  15. blasjw
    Sure, no problem.  If I swap out the chips, I will post an update.  So far, I just partially re-capped the power supply, socketed the 4 main digital ICs and the op-amps which I replaced with OPA627s. I'm still waiting for some additional caps for the power supply and some for the analog output stage to arrive.  Have some additional mods in mind for the future as well.
    Yes, that's correct.  The CS8414 is SOIC but fortunately, it's readily available on eBay with the adapter if you don't like soldering SMT. 
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