USB to SPDIF ? skipping dac / interface and going digital only with Genelec GLM Kit.

[Danks]

Dear ASR's

hence the title,

The 8331 has AES/EBU digital inputs, so I need a way to output a compatible digital signal from my computer. (Macbook) (used for pro mix/mastering purposes)
I obviously need USB-to-digital converter (like a USB to SPDIF/coaxial box) and then a coaxial-to-AES/EBU adapter (or cable). right?

GLM software can control the volume digitally without degrading sound quality, maybe i'll get the external volume control by Genelec (9310BM) they charge 85 Euro for a Metal Knob but Hey it's Genelec . but this means I don’t need a dedicated DAC or preamp for volume control. I sold by RME Babyface cause it couldn't handle my Hifiman Arya Organic (Got the JDS Element IV instead)
my main concern is the Reliability of cheap USB to SPDIF devices cause some USB-to-coax adapters may have jitter or driver issues.

so my main question is can anyone recommend a good USB to SPDIF (coaxial) adapter, that won't introduce Jitter or other artifacts?
RME Digiface costs 400 Euro and would be completely overkill.
or maybe should skip digital-only?

help -)

 

[Danks]

edit, i think AES/EBU would make more sense as its more immune to noise as S/PDIF ? sorry i am pretty new to this..

 

[Rednaxela]

Anything in here?

USB to AES converter

I want to convert a usb output from a MacMini to an aes/ebu connection on an active speaker. I’ve seen some devices that do this but they are very pricey. Like this https://www.matrix-digi.com/product/82/X-SPDIF3 This device costs $500. While I’m sure this would do the job it’s alot more than I...

www.diyaudio.com

 

[Rednaxela]

coaxial-to-AES/EBU adapter

For a similar use case I'm looking at this unit myself.

Neutrik NA2 FP MF

Adaptor Plug From XLR female to RCA socket, Wired in accordance with IEC 268-12, Pin 2: Signal, Pin 1 and 3: Connected to ground, Colour: Silver

www.thomann.co.uk

I'm no expert, but at least one reviewer states that it does the trick for them.

 

[mcdn]

Topping D10 balanced and a cable with coax on one end and XLR on the other should do it. Or Audiophonics have something with a native AES XLR output: https://www.audiophonics.fr/fr/inte...aes-i2s-2x-tcxo-otg-24bit-192khz-p-10547.html

Don't worry about audio quality. bits are bits.

 

[phofman]

maybe i'll get the external volume control by Genelec (9310BM) they charge 85 Euro for a Metal Knob but Hey it's Genelec

IIUC there is just a standard log potentiometer inside https://www.diyaudio.com/community/...r-remote-volume-control-diy-prototype.306512/ https://gearspace.com/board/high-end/1279456-diy-genelec-glm-adapter-volume-controller.html

 

[phofman]

For a similar use case I'm looking at this unit myself.

IIUC that is XLR (differential) -> RCA (single-ended). The opposite direction would either produce non-differential signal (which may work OK anyway but the advantages of the differential path are lost), or an active solution with differential line driver.

 

[Rednaxela]

@phofman

Thanks. So do you advise against using the unit as a

coaxial-to-AES/EBU adapter

, or is it a headsup re. going

coaxial-to-AES/EBU

in the first place?

Open question. Genuinely trying to get what you say.

 

[phofman]

A correct conversion between single-ended (RCA SPDIF) and differential (AES/EBU XLR) cannot be passive, it requires an active line driver which generates the negated signal for the differential line. That device is a convertor in the other direction - differential -> single-ended which can be done passively (only one line of the differential pair is used). It may work (because there is still a signal difference between signal line and 0V, half the level), but the advantage of using a differential signal is lost (rejection of common-mode signals). It may not be a problem if the line is short, likely you may not even notice it. The differential version uses higher voltage levels but again if the receiver is OK with the low levels of SPDIF, it may work too.

To sum up - it may work perfectly fine, but is not technically correct.

 

[Danks]

IIUC there is just a standard log potentiometer inside https://www.diyaudio.com/community/...r-remote-volume-control-diy-prototype.306512/ https://gearspace.com/board/high-end/1279456-diy-genelec-glm-adapter-volume-controller.html

ufff, that's a bit too advanced for me, can't DIY, hardly any knowledge about this. still very interresting. ty

 

[mcdn]

A correct conversion between single-ended (RCA SPDIF) and differential (AES/EBU XLR) cannot be passive, it requires an active line driver which generates the negated signal for the differential line. That device is a convertor in the other direction - differential -> single-ended which can be done passively (only one line of the differential pair is used). It may work (because there is still a signal difference between signal line and 0V, half the level), but the advantage of using a differential signal is lost (rejection of common-mode signals). It may not be a problem if the line is short, likely you may not even notice it. The differential version uses higher voltage levels but again if the receiver is OK with the low levels of SPDIF, it may work too.

To sum up - it may work perfectly fine, but is not technically correct.

To alternately sum it up, it is technically fine. The differential receiver sees pin 2 (hot) from the sender, pin 1 (shield), and pin3 (cold) both connected to the sender's ground [note, other wiring options are available, it doesn't really matter for these low bandwidth low distance situations]. The differential signal is then received perfectly fine as the difference between pin 2 and pin 1. Maybe not over a hundred metres in an auditorium, but certainly without problem in a house.

 

[Danks]

ty for all the answers so far friends!
seems a bit complicated. maybe i should just use the RCA outs of my JDS 4 and connect them via RCA to XLR to my Genelec, and just use my GLM Kit for Room Correction?
if use it nearfield so my cables are very short, maybe i can get away w/ little to no noise. otherwise I would have to buy a a passive RCA-to-XLR transformer (like Neutrik NA2F-D0B-TX) (not the Neutrik Na2 FP MF that @Rednaxela mentioned, as it's the other way around?)
I was just cruious what possibilities are left to use the GLM Kit, since it's 315 Euro and just a one trick pony.

​

 

[staticV3]

so my main question is can anyone recommend a good USB to SPDIF (coaxial) adapter, that won't introduce Jitter or other artifacts?

The SMSL PO100 2024 is great and supports UAC2 Hardware volume control, so you can continue using the default OS volume controls in macOS.

A simple Coax to XLR cable is usually sufficient:

https://support.genelec.com/hc/en-us/articles/360019582539-Can-I-connect-my-digital-SAM-monitors-to-S-PDIF-coaxial-directly

 

[Danks]

hmm maybe this: https://audiosciencereview.com/foru...oing-digital-genelec-9320a.57080/post-2086108

 

[Danks]

The SMSL PO100 2024 is great and supports UAC2 Hardware volume control, so you can continue using the default OS volume controls in macOS.

ahh i've waited for you )) ty

 

[juliand]

A correct conversion between single-ended (RCA SPDIF) and differential (AES/EBU XLR) cannot be passive, it requires an active line driver which generates the negated signal for the differential line. That device is a convertor in the other direction - differential -> single-ended which can be done passively (only one line of the differential pair is used). It may work (because there is still a signal difference between signal line and 0V, half the level), but the advantage of using a differential signal is lost (rejection of common-mode signals). It may not be a problem if the line is short, likely you may not even notice it. The differential version uses higher voltage levels but again if the receiver is OK with the low levels of SPDIF, it may work too.

To sum up - it may work perfectly fine, but is not technically correct.

That's a lot of words to say "I have no clue about how transformers work".

 

[phofman]

That's a lot of words to say "I have no clue about how transformers work".

Well, I do not see how a passive transformer could provide the specced AES/EBU levels from SPDIF. IIUC SPDIF is specced 0.5V to 75 ohm, which is 3.3mW of power. This power, transformed to 110 ohm of AES/EBU, can at most (with 100% efficiency transformer) generate 0.6V which is way below the specced 2V minimum for transmitter (2 - 7V). While there are passive transformers, e.g. by Neutrik, I do not see how they could generate specced AES/EBU signal from specced SPDIF signal. E.g. a discussion at https://www.audiophonics.fr/en/vari...r-spdif-coaxial-75-to-aesebu-110-p-16821.html - translating the french response:

Message from Audiophonics service
Do not use coax to AES cords. They do exist but do not correspond to any standard and do not respect the necessary impedance. This product is active and has an internal battery, it is indeed necessary to recharge it.

So IMHO it still holds - it may work perfectly fine, but is not technically correct, even if there was a transformer inside (which almost certainly is not).

 

[multichannel_guy]

so my main question is can anyone recommend a good USB to SPDIF (coaxial) adapter, that won't introduce Jitter or other artifacts?
RME Digiface costs 400 Euro and would be completely overkill.
or maybe should skip digital-only?

help -)

The SMSL DP5 SE is a high quality device that will take a PC USB input and give you a aes/ebu output. Analog XLR out could be used with some 2nd setup, it could be a multitasker.

https://smsl.shop/products/dp5se?srsltid=AfmBOoou-g9YYHgUJDuejWZrJalDBLXW4nG06WWDUEmeiRGkE8_n2P4r

 

[Danks]

thanks! but i am looking for no new devices at this point, happy with my jds labs element 4

 

[soundwave76]

Any ideas here for an USB-AES interface with airplay streaming capability? SMSL SD-9 seems to be the only one I can find, which doesnt break the bank, though it’s discontinued. I have a working digital Genelec desktop system, but I now need to connect a Macbook to the same system and switch between both.