Is the XLR Input AES/EBU? Is this better than using the USB?

Hi folks,

I’ve been enjoying my Directstream these past 4-5 months, but have recently been wondering if I might get SQ and stability improvements by replacing my Mac Mini (2014 SSD with a linear power supply) and its USB connection (Audioquest Diamond) with a new Aurender device that has AES/EBU (and SPDIF etc) digital outputs.

  1. What’s the view on the Directstream’s SQ differences between USB and AES/EBU? Or would you pick another one (e.g. SPDIF)? The HDMI I2S connection isn’t really an option because I haven’t yet found a good source device with a decent iOS remote app…

  2. Is the XLR connection at the back of the DS an AES/EBU one?

Many thanks in advance and apologies for these newbie questions!


That is an AES/EBU input. I’ve never used it so can’t compare to the USB. I suspect which one is better is more a function of what it is connected to than the type of connection itself.

The Digital XLR in on the DirectStream is AES/EBU - and (for those that might be worried) unlike balanced analog it doesn’t matter what polarity the pins are with AES/EBU.

Personally I use USB just because it supports DXD (32 bit floating PCM at 352.8k) and double rate DSD and AES/EBU, S/PDIF and TOSLink top out at 192k (or often 96k for TOSLink)

Which sounds better is very system dependent: USB can be worse because of the 5V noise or better with better grounding.

In general AES/EBU has more common mode noise rejection than S/PDIF, but this often isn’t an issue for the shorter digital cables we tend to use in home audio. Except for 110 Ohm termination instead of 75 Ohm termination the DS uses the same receiver circuit for both.

Higher quality sources often swamp the differences between different digital inputs and in fact coming from the same source with a common ground I2S, AES/EBU, S/PDIF and TOSLink all sound essentially identical.

[Edit: stevem2 beat me :) ]

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One issue with USB is that those sources that offer dual femto clocks cannot utilize this over USB, but over AES/EBU this may give a change for the better.

With the DS (and many DACs) USB is running asynchronously and is locked to the DS’s clock.

I use a Bryston BDP-2 as my source, and I have it connected with both the Shunyata Venom USB and the Shunyata Zitron Anaconda AES/EBU.

I have also tried a Cardas Lightnng USB and Audioquest Carbon USB cables.

I easily prefer the AES/EBU connection. The cable costs at least 3 times as much as the USB’s, but it’s worth it to my ears.

I kept the Venom USB however, so I can switch to it on the rare occasion I listen to DSD.

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Many thanks for the quick responses folks! Always amazes me how responsive this community is!

Special thanks to Ted - I hadn’t realized about the sample rate limitations for the non-USB connections. This is a bummer as I have an increasing collection of DSFs I rip from SACDs.

One of the reasons I was thinking of making this change is as I’m trying to track down/reduce the source of some noise in my system. It used to be perfectly black before my recent equipment changes (macbook —> mac mini (but with linear power supply), Chord Hugo —> Directstream, Woo Audio WA5 —> WA234 monoblock amps), but now I get a distinct (though admittedly faint) crackling and squealing every so often (noticeable especially when using headphones).

The crackling disappears when I disconnect the source cables leading into my amps, so it looks like the problem is upstream from them…

There was quite a bit of improvement when changed my Directstream->WA234 from Chord RCAs to Nordost Valhalla2 XLRs last week, which is why I started thinking about trying a different connection between the Mac Mini and DS.

A friend suggested I try removing the ground pin on my main power cord, but I haven’t dared do that yet, and not sure if it will make a difference (I’m using a P10Power Plant and Valhalla 2 power cables). Do any of you think this will make a difference? Or could it be the Mac Mini, even though I’ve replaced the power supply with a linear one (Uptone Audio JS-2 and MMK kit)?

Just to be clear - S/PDIF and AES/EBU do single rate DSD (e.g. ripped SACDs) fine. Some TOSLink cables in some systems also do single rate DSD. They just don’t do double rate DSD (much more rare, but becoming more available for download.)

It might be worth running the bitperfect test to see if the source of some of the crackling is either a bad digital connection (unlikely) or upstream processing (a little more likely.) This probably wouldn’t explain squealing tho.

Crackling makes me think tube, or tube pins.

I do not even have a guess for squealing.

(I also have a WA5. Very nice headphone amp.)

I had my computer usb output connected to a M2tech Evo stack using its AES/EBU output for the DS. I have since changed to just using the computer usb output connected to the DS input. I can’t say that there is any difference in sq for my system. I was using a Transparent AES/EBU cable and am now using the Acoustic Revive usb-1.0sps so I was using very good cables in both cases.

I mostly changed because my system using Jplay6 and AO is very stable now. Before it would some times crash which I think was a problem with the computer/Evo connection.

Thanks again for all the great suggestions! I just purchased an UpTone Audio “Regen”, which hopefully will increase the signal/noise in my USB connection. Let’s see if that helps the situation. If not I may see if it goes away if I put back the Macbook I was using previously. Can’t be the tubes as there is no crackling from the speakers/headphones attached the the amps if I disconnect the source…