After owning a non-DSD (no FireWire interface) Delius for a year, I recently found a sensibly priced Purcell upsampler (Purcell is later version, with integrated FireWire).
So I’ve connected it up using dual-AES, and am happy with the upgrade upsampling to 176k.
However, I made my own cables and used standard Neutrik Swissflex NX2 studio cable I had to hand. I also made them 1.5m long.
I’ve no problems locking to signals, but my question - is there an audible difference if I swap to proper 110 ohm cable? And does the length of cable matter (Ionly need 30cm as they’re stacked currently :))?
Congratulations on finding a matching Purcell. Classic dCS sounds really good still.
True 110 Ohm digital cable might be better if you would like to try, if you can then try at least 1.5m lengths. This is said to be better due to reflections in the cable.
VanDamme green digital are a pretty good budget option to start with.
Thanks August - Neutrik cables are pretty good, and my go to for audio use given I have so much of it. What I’m interested in has anyone heard a difference moving to proper 110 ohm, and is the 1.5m recommendation relevant for AES/EBU operation?
That is almost impossible to say as cables may sound different to each other even if all are specified as 110 ohm. As there is no firm or universally accepted audible correlation between any electrical or physical characteristic in properly manufactured audio cables it is difficult to isolate the subjective impact of a single characteristic. Further it cannot be predicted whether or not you may be sensitive to the change nor the value that you may place upon it.
Nevertheless keeping to the manufacturer’s or industry standard bodies’ specification is good practice and should enable the most efficient electrical path. Though subjective audibility to individuals cannot be predicted.
Good cables properly specified as 110 ohm and properly terminated are available for quite reasonable sums. ( well under £100 pair). I can only suggest risking the small investment in such a pair and finding out for yourself how they compare with your home brew pair. Or even better find someone to loan you some.
As several people here have pointed out the 110 Ω specification for AES3 is designed to eliminate impedance mismatches along the transmission line. These cause signal reflections which can cause jitter. Since the characteristic impedance is part of the actual specification is it generally a good idea to adhere to it if you want things to work properly.
The relevance of the cable’s length is that it will determine whether or not any reflections arrive within the rise time “window” of the original signal, if they do they are far more likely to cause jitter. Signal rise times differ from transmitter to transmitter and are a compromise. The ideal rise time from a signal perspective (very short) would mean the transmitter would generate a lot of EMI which could cause the device to fail emissions tests. So most commercial products have transmitters with slower rise times which increase the risk of reflections interfering with the signal if used with shorter cables. The 1.5m guideline is a very rough rule of thumb for most transmitters when used with most cables, it is not part of the AES3 specification.
How audible any jitter is will depend on how much is being generated and how good the receiving equipment is at rejecting it. Jitter is quite easy to measure (if you have the right equipment) but is difficult to “hear” since it doesn’t have a characteristic sonic signature. It is quite diffuse and can manifest in different ways such as a lack of focus or a sense of roughness. It’s easier to hear when it is reduced or removed, the music seems more “natural” and “makes more sense”.
As far as your “home brew” cable is concerned I am familiar with Neutrik connectors but not with their cables. What sort of cable is this Swissflex NX2 exactly? I can’t find any trace of it on Neutrik’s website. Have you measured the characteristic impedance? That might be a good place to start as it would tell you whether it is in spec for AES3 or if not by how much.
So what’s the bottom line? Well, maybe you don’t have a problem at all and even if you do it might not be audible. The only real way to find out would to be to compare your cable with an in-spec 110 Ω AES3 cable by listening.
OK, looks like a standard microphone cable, so designed to avoid reflections in the analog frequency spectrum, not digital. Likely then that the characteristic impedance is well below 110Ω. It will be interesting to hear what if any difference you perceive with the Mogami. Please report back!
Got the delivery from France today - they gave me more cable than I ordered so I made up a 30cm pair initially as my Delius and Purcell are stacked (still have enough cable to make a 1m pair if I need to).
Made up the cables and just swapped them out - initial response, bass seems a bit more textured, but really hard to say at this level - will keep them in for a few weeks and then swap back to the 1.5m long microphone 75 ohm cable. If nothing else, much tidier behind my rack now
My two cents.
Mogami 3080 is my standard AES/EBU cable and is widely used by professionals as well.
The thicker Mogami 3173 might be an alternative.
Recommended are Neutrik’s 3-pole XCC Series for even better HF protection, but they require a crimp tool.
Thanks all, can’t see me changing from the 3080, system sounds great. I’ll still swap back in a few weeks just to see if I notice a difference…think I do, but I did invest 30 mins in making them up
Just a standard but good audio grade studio cable.
