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Coax Digital Out -> XLR Digital Input cable?

Discussion in 'Audio Hardware' started by sangbro, Jan 14, 2021 at 3:03 AM.

  1. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    Hello,

    This is for Blue Node 2i Streamer -> Boulder 866 Int Amp.



    Blue Node 2i has Coax digital out (coaxial rca out from blue node 2i)

    And Boulder 866 has XLR digital input (3-pin xlr convertible to s/pdif on rca).


    For this connection, can I use this kind of cable? (RCA to XLR Male)


    Mogami Gold RCA Male to XLR Male Cable (20')


    Thank you.
     
  2. shug4476

    shug4476 Forum Resident

    Location:
    London
    It must specifically be digital unfortunately. You would need a converter.
     
    sangbro likes this.
  3. Oatp1b1

    Oatp1b1 Forum Resident

    Location:
    Sweden
    You should use RCA->XLR cables from the analog outputs of the Node 2i to the analog inputs on the Boulder. E.g. Monoprice sells cables like that.
     
    sangbro likes this.
  4. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
  5. Jim N.

    Jim N. Get off my lawn, punk, or hear my Mossberg sing!

    Location:
    So Cal
    sangbro likes this.
  6. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    The cable I link in the thread has the same shape as the Monoprice one.

    I also happen to find the cable used Canare.

    Sescom Canare Star-Quad 3-Pin XLR Male to RCA Male Audio Cable (6', Black)

    They all look same. I’m wondering there is any other specific point that I need to check.
    Like there is “digital specific?”
     
  7. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    Thank you.

    This is indeed very confusing to me. I try to google search but some said ohm doesn’t really matter in my case (and just use the cable)
    Like this
    Sescom Canare Star-Quad 3-Pin XLR Male to RCA Male Audio Cable (6', Black)

    And there are other people saying impedance is critical like you stated.
     
  8. Jim N.

    Jim N. Get off my lawn, punk, or hear my Mossberg sing!

    Location:
    So Cal
    Try the cable first if it is cheap enough. If it works, great, but I have serious doubts that it would. However I have not tried it so I cannot speak about it from experience. The RCA/XLR cables are mainly for audio and microphones. You can have RCA/BNC cables because they are both 75 ohm. I saw some posts about this awhile back in other forums and am simply repeating what was said there.

    Why not contact Boulder? The HiFi plus review of the 866 states that it lacks SPDIF input so maybe the manufacturer has a solution. I read the manual and ask them how you would convert from digital AES to SPDIF RCA as stated is possible in the manual.

    Also it looks like your Blue Node has optical out and the Boulder has optical in. Get a decent toslink cable.

    And there is also this: Hosa CDL-313 S/PDIF Coax to AES/EBU Digital Audio Interface
     
    Last edited: Jan 14, 2021 at 6:06 AM
    rodentdog and sangbro like this.
  9. Lowrider75

    Lowrider75 Forum Resident

    Location:
    Philadelphia, PA
    That is an an unbalanced analogue cable, not applicable for digital.

    This would be the way to go. No worries about connectors and impedance.
     
    sangbro likes this.
  10. Vincent Kars

    Vincent Kars Forum Resident

    Location:
    Europa
    sangbro likes this.
  11. Sterling1

    Sterling1 Forum Resident

    Location:
    Louisville, KY
    sangbro likes this.
  12. Sterling1

    Sterling1 Forum Resident

    Location:
    Louisville, KY
    Yep, no worries, optical Toslink is S/PDIF. Now, a sidebar, there is a good reason to connect digital recorders to AES-EBU rather than coax or optical S/PDIF as AES-EBU receivers are not subject to receive and transmit SCMS data, unless instructed by user.
     
    sangbro likes this.
  13. timind

    timind phorum rezident

    Location:
    Westfield, IN USA
    sangbro likes this.
  14. Vincent Kars

    Vincent Kars Forum Resident

    Location:
    Europa
    Of course one could connect the units analog as well.
    I do think if you fork out $14,450 for the analog+digital version of the 866 instead of $12,250 for the analog only version, you want to give the digital part a shot.
    Would be a pity if the DA conversion of the 866 is not able to beat the $ 549 Node.
    But certainly something to try in a direct A/B
     
  15. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    I contact them both. :( Has been couple days.

    Due to Covid, their response gets too delayed / non responsive. I need to figure out something for now.

    I broke Toslink flap door already so I’m not a fan of it but it seems I need to use it. I’ll just tape it to fix the cable.
     
  16. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    I broke the toslink flap door. So I now have cable in with duck tape holding it.
     
  17. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    I asked. Has been couple days.

    I need to contact them again. It’s a small company.

    Anyway I just plug in toslink with duck tape. (I broke the flap door.)
     
  18. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    Lowrider75 and timind like this.
  19. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    I used to use node 2i for different active speakers. Node 2i’s dac is pretty good considering the price.

    Boulder 866’s dac is in a totally different level. It’s not even $2500 difference between analogue / digital version. I think the key is optimized integration. I’m dare to even say that 866’s DAC is around $10k level quality if you like Boulder’s sound.
     
  20. Black Elk

    Black Elk Music Lover

    Location:
    Bay Area, U.S.A.
    Firstly, given the cost of their products, hugely disappointing to read the user manual for your Boulder amp and not see more about how to use the AES-EBU interface.

    AES-EBU and S/PDIF were both developed to work with standard analog audio cables, so, provided you are only using a short run, any analog XLR to RCA cable should work.

    You do not need a 75-ohm cable because there is no such thing as a 75-ohm RCA!

    Due to the much greater cable lengths needed in recording studios and broadcast situations, a 110-ohm, transformer coupled system with EQ was standardized for Pro situations, and those cables need to be identified as such, but transmission over standard balanced audio cables is still possible within studios.

    The frame contents are subtly different for AES-EBU and S/PDIF, but this should not matter for simple audio playback. The biggest difference is in operating signal level, so I presume the Boulder unit is capable of identifying and decoding the much smaller S/PDIF signal.

    Good luck!
     
    sangbro and Jim N. like this.
  21. Davey

    Davey like smoke from a lithium dream

    Location:
    SF Bay Area, USA
    Probably a dumb question, but why not just use the network connection on the Boulder instead of using the Bluesound? I guess if you are already fully invested in the Bluesound streaming apps, may not be the best solution.
     
    sangbro likes this.
  22. Jim N.

    Jim N. Get off my lawn, punk, or hear my Mossberg sing!

    Location:
    So Cal
    Black Elk knows his digital so go with what he says.
     
    sangbro likes this.
  23. harby

    harby Forum Resident

    Location:
    Portland, OR, USA
    - The Node has optical digital out. The integrated amp has optical digital in. That would be the first option.

    - The second option is to use transformers for SP/DIF to AES. The Neutriks below with a BNC would also need a BNC<>RCA cable. Note that XLR is unidirectional, below, the -M adapters are the AES3 output.

    [​IMG]

    The signal level of AES3 is specified differently. Matching the impedance doesn't solve the signal level mismatch. Since the integrated amp says it can use "converters", it will likely still detect the lower levels from SP/DIF conversion.


    - The only correct way to interface with pro gear is with full digital conversion.

    [​IMG]

    AES3 is not just a physical interface and signal level, it is also special subcodes and formats. Right off the bat, bit 0 of the channel status byte indicates if it is professional or consumer, and besides SCMS copy protection, there are other bits that have different meanings in the professional protocol, such as reference levels. This amp's AES3 is likely consumer chipset wrapped in an XLR upsell, though, so there is less chance of it locking up on bad bits. It is more likely to choke on pro AES3 from my Apogee.
     
    Last edited: Jan 14, 2021 at 5:55 PM
    sangbro likes this.
  24. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    The almost only problem I have with Boulder indeed. Boulder even makes the converter for this connection. So... I don’t know.

    I will get a converter to make this happen.
     
  25. sangbro

    sangbro Active Member Thread Starter

    Location:
    Costa Mesa
    Long story short, Apple doesn’t want to work with Boulder, so Apple blocks Boulder’s capability for Airplay.

    I basically need Airplay and Idagio Streaming - without this I need both Roon and Qobuz accounts plus Roon core.

    I try this and personally don’t find any real advantage for me (Sound Quality wise too. Most of music I listen to only available for CD quality.
    Also little up sampling from 16/44 with Qobuz doesn’t provide any perceivable advantage for me.)

    I only use Blue Node 2i as a streamer, and it is a great streamer.
     

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