Audial S5 settings question
I recently received a used Audial S5 that I purchased (I believe the owner notified Pedja via email). It has the optional rca transformer coupled outputs. I have the Audial connected to a bluesound node 2i (rca coax out) to the Audial Bnc (rca to bnc cable). It was not clear to me from the manual which setting I should use on the D/PLL/PA switch? What does each of these settings refer to and what exactly do they do. Apologies in advance if this question had been already answered. My second question is as follows. Assuming I am using the transformer couple rca outs, what would be the best option in terms of rca interconnects. Shield connected to Audial S5 ground connection or shield tied to ground at amplifier connection? It has only been a couple of hours so far but I am loving this DAC. Sounds amazing feeding into my OTL amplifier and ZMF Atrium headphones.
Yes, regarding the PLL mode switch, the S5 user manual information is not complete and requires an update in this part.
The S/PDIF inputs (applies to both BNC and optical) retrieve the sampling clock from the incoming S/PDIF stream, by using the PLL. This PLL is a classic, analog PLL, and it can operate in two ways: by using the S/PDIF data, or by using the S/PDIF frame pre-amble. If it locks on data, the susceptibility to data-related jitter is higher. If it locks on the pre-amble, the PLL's intrinsic jitter is higher. Generally, better results can be achieved with "data mode", however "pre-amble mode" is a great help with sub-optimal sources.
On the S5 page, you will find a jitter performance graph showing the difference between these two modes when S5 is used with a mediocre S/PDIF source.
Also, please note that the PLL mode change requires the restart to take the effect, so once you change this setting you also have to turn the S5 off (waiting for 10 seconds to let all the caps discharge is good practice) and on.
Regarding the interconnect cable, the term shield can be a bit misleading, taking into account different cable geometries. First, please note that you anyhow need the audio ground (return) paths connected at both cable ends. The shield which can (and should) be connected at one end only is only an "additional", or outer shield in the case of co-axial cables with a so-called double shield. I normally connect this (outer) shield at the source, so in this case, it would mean at the S5 (and for this purpose you can use a dedicated GND connector at the S5 backplate). However, most of my cables are not shielded at all and are made of two wires only, one for the signal, and the other for the ground, so with no shield at all.
Thank you for the fast response. From my brief listening session last night I did seem to prefer the data setting. The wire I am using to make my interconnects has two conductors and a separate shield. I usually only tie the shield to ground at the source but was unsure about how the transformer coupled connection affected things. I will make up some cables using the Audial ground connection as per your suggestion.
Yes, that is what, in my view, should be done. But transformer coupling indeed requires a bit different approach or at least more things to consider, sorry for not fully explaining this particular case.
First, the "outer" shield is generally best connected to the ground in a way that does not disturb the audio ground (return) path. It should be treated like an extension of the chassis, let's say similar to the XLR pin 1. And that is why the S5 GND connector can be handy (because it is the chassis earth/ground).
Transformer coupled interface makes a difference since it is essentially floating, and if you connect the outer cable shield to the ground tap of the coupling transformer (i.e. to the ground of the RCA connector of the transformer coupled output), it would have its path all along the cable ground lead to the other device ground connection (provided the other device input is classic, and not transformer coupled). Hence this would be an exception, and in this case it would be preferred to connect the shield to the ground on the other side.
But as I said, the S5 GND connector is really useful here.
Once again thank you for sharing knowledge. I will get to work making a set of interconnects. Shield separated from the hot and return at both ends and then tied to the external ground connection of the Audial. Only my second night of listening but still absolutely loving this dac. The combination of detail retrieval with the organic/analog sound is so much fun. Lastly I was not prepared for how heavy this component is. It is one thing to read that there are 10 separate power supply's, it is another thing to lift it in real life 🙂