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Any quality loss by using SPDIF?

Discussion in 'Recording' started by Johnjm22, Aug 29, 2004.

  1. Johnjm22

    Johnjm22 Guest

    Is there any quality loss by transferring digital information via an RCA SPDIF connection?

    The reason I ask is because I want to take in 10 inputs at once on my digi 002 at 96k.

    I was planning on going from a Rosetta's RCA SPDIF output into my 002.
     
  2. David French

    David French Well-Known Member

    The quick answer is "No". Just make sure you use a true 75 ohm cable.
     
  3. Kurt Foster

    Kurt Foster Distinguished Member

    Actually, the quality will be better most likely due to bypassing the cheezy 002 pres and converters .... especially if you are using a high quality mic and mic pre in front of the Rosetta ....
     
  4. Johnjm22

    Johnjm22 Guest

    Thanks for the quick replies. I am extremely happy to hear that. :D

    I had read somwhere on these boards that if you used SPDIF it would smear the high end.

    Yeah I plan on getting a sebatron vmp-2000e. I can't wait to hear how it sounds going through my rosetta!!!
     
  5. Ammitsboel

    Ammitsboel Member

    That's another story but you will only have degradation(Jitter) of you have a bad clock... +Jitter also happens in AES/EBU and most of all in Light pipe.

    Basically there is no difference in bit to bit transfering when using SPDIF, AES/EBU or light pipe but to understand more about this you can visit http://www.digido.com

    Best Regards,
     
  6. Kurt Foster

    Kurt Foster Distinguished Member

    I can't see why .... s/pdif (sony/phillips diigital interface) is simply a digital transfer protocol ... As David pointed out, as long as you use a true 75 ohm cable and keep the run to a reasonable length (less than 10 feet / 12 meters) , there should not be a problem. ADAT lightpipe runs longer than 12 meters can introduce jitter as well ....
     
  7. Opus2000

    Opus2000 Well-Known Member

    Optical at any distance is worse than anything. By nature it's got jitter due to the reflections within the cable. If you used the Glass Fiber ADAT cables that would be reduced greatly.

    SPDIF and AES will "sound" the same in the long run.

    The only way SPDIF would kill the high end is if the box that is outputting it was not designed properly!

    Being the Apogee tech that I am I can tell you the Rosetta AD is built very well of course :)

    Opus
     
  8. Kurt Foster

    Kurt Foster Distinguished Member

    Opus,
    Do you know who has these glass fiber ADAT cables available?
     
  9. Johnjm22

    Johnjm22 Guest

    Okay I'm a little bit confused. Are you now saying that transferring digital information will cause jitter no matter what?

    Is an RCA cable considered optical?
     
  10. Kurt Foster

    Kurt Foster Distinguished Member

    John, No .... Opus means an optical cable like the ones used for ADAT lightpipes.. aes and spdif don not have those problems ...
     
  11. Johnjm22

    Johnjm22 Guest

  12. maintiger

    maintiger Well-Known Member

    there is definitely an improvement in the sound
    when I use my pres via the rosetta into the motu 828 mkii than when I go into the 828 from my pres using motus AD. Also if your program allows use the rosettas word clock or even the spdif instead of your normal clock. you will notice that everything will be tighter, especially the drums.
     
  13. Kurt Foster

    Kurt Foster Distinguished Member

    Xavier,
    Try clocking the MOTU off the Rosetta if you can . I suspect the MOTUs conversion will approach that of the Apogee when re clocked by the Apogee.

    Many of the high end convereters that employ ADAT lightpipes, use the same chips from ALESIS ... the difference is in the analog circuts and the digital clocks.
     
  14. Johnjm22

    Johnjm22 Guest

    I think he's talking about these:

    http://apogeedigital.com/products/wydeeyecables.php

    BTW, I see that SPDIF coaxial cables are available in 75ohm and 110ohm, why do they make them with different amounts of ohm's?
     
  15. David French

    David French Well-Known Member

    Never heard of a 110 ohm SPDIF cable. Perhaps you're confusing it with the AES/EBU protocol, which uses a 110 ohm cable.
     
  16. Johnjm22

    Johnjm22 Guest

    Yeah, your right they just have 75ohm. The way they wrote it on there website made it kinda confusing.
     

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