Knowledge is power, but experience is knowing
This is my third instalment for my experiences of testing and messing around with different networking solutions, mostly SFP based, to see if there is a better way I can recommend to you to achieve the best sound quality experience from streamed music. I have had a passion for this dating back more than a decade when I started building my own dedicated to music computer servers, something we all take for granted these days. This whole process has reminded me of getting into vinyl for the first time, something I did only about two years ago so its still a fresh memory. By this I mean I started with a goal but only knowing a little about the topic but gradually the more I explore, test and research the clearer things are becoming, helping me see the wood through the trees, especially when it comes to other people’s information and suggestions.
One of the greatest things about audio is the community, the other like minded audiophiles that seem to find you when you are out there and open minded enough to learn. I have to thank Tom Weustink who contacted me after my last article suggesting I look into the DAC cable. What’s been interesting about this is the DAC cable or Direct-Attached Copper is designed as a short distance alternative to using fibre optics for SFP networking, so it’s not designed to be used to send a signal from a computer music server to a DAC, however that is how I have found a great use for it.
SFP and HiFi Rose
One of the main digital front ends I have been using this year has been the HiFi Rose RS130 music server and the HiFi Rose RD160 DAC and these products are what catapulted me down the SFP rabbit hole to begin with. That is because with the RD160, Henley Audio, UK distributor for Rose, also sent me an SFP fibre cable that is HiFi Rose branded to some degree, to connect between the server and DAC instead of a traditional maybe USB or other digital connection. So essentially a fibre optic link between the music server and DAC and I was excited by this as I could see some potential benefits such as galvanic isolation of any noise transferring between to the very important DAC.
However in practice testing between the Rose SFP cable link and my preferred USB cable, the Tellurium Q Statement II, I did end up preferring the SFP fibre but not in every regard. What was interesting is my experiences and how they closely mirrored what I have been hearing when comparing SFP fibre for networking compared to copper based RJ45 and CAT cabling. I detailed my findings in my RD160 video review found here but in summary there seemed to be more slightly more clarity and detail using SFP where masses of music energy had detail and layers to them that there were slightly mushier sounding when using USB, however USB had a more bold and more warm tonally pleasing presentation, so fibre sounded cleaner but leaner. I concluded that SFP was the better of the two, however I felt something just was not complete here or could be better, I had no idea what that might be at this stage.
Roll on several months and now with all of the other SFP testing I have done I could start to see things more clearly, however a situation was forced on me. I had been listening to the Eversolo A10 music server with dual Eversolo F10 power amplifiers for a few weeks to complete their reviews. Going back to the Rose setup I could not get the RS130 to see the RD160 DAC using the Rose SFP fibre cable, clearly something was wrong with it. I am wondering if something was wrong from the start as I found the link was a little temperamental, sometimes the RS130 would auto select back to USB like the SFP connection was lost, but I didn’t know any different to see this as anything more than user error. However a total failure is not my fault, I hope, but it prompted me to look for an alternative solution.
SFP+ and the DAC cable
One of the things that confused me initially was the difference between SFP and SFP+ and what did I need or not need to use? With the Eversolo A10 it says specifically on the website to use SFP only and not SFP+. Doing some research it seemed like the HiFi Rose also needed SFP only and not SFP+ for its network connection. The SFP fibre modules I purchased recently link, as detailed in my SFP exploration part II article have been working fine with both the Rose and Eversolo so I was confident I had this right at least.
One thing that has been different about the SFP cable link between the Rose server and DAC is that its using a different type of SFP module and only a single fibre cable or simplex compared to the networking SFP that uses dual fibre cables or duplex. That has had me confused as to why and now I needed to replace this broken link I needed to better understand it. I looked at the SFP modules Rose use for their branded solution and it turns out they are SFP+ 10Gb Base-T modules and so I went looking for a solution.
At the same time I am doing all of this I was also considering purchasing a DAC cable to test for networking uses to see if it might be a better sounding solution compared to using fibre. The DAC cable has SFP modules at either end of the cable the same as with fibre, however instead of fibre optic cable, shielded copper is used and this is intended for short signal runs as HiFi is, at least for me 1-2 metres is all I needed. So straight away there is the obvious difference here of no conversion process to and from light and maybe that would sound better, however do we still now get galvanic isolation? I guessed probably not. The great thing about networking solutions is that they are not expensive to buy to test, but getting them is not always as easy as going on Amazon.
Luckily there is an excellent supplier in FS.com and they had everything I needed and more. I had the SFP DAC cable that is Cisco compatible in my basket with a total delivered cost of £22.80 and I thought at that price it would be worth also buying an SFP+ 10G DAC cable to test between the Rose server and DAC as well. With its total delivered cost of £19.80 yes I had spent more money on this exploration but it was within what I felt was ok if the testing proved fruitless, but the result ended up not being far from that and better than what I expected.
The irony of being called a DAC cable
Its worth pointing out as a reminder that a DAC cable has nothing to with HiFi DAC’s, its short for Direct-Attached Copper, however maybe there is more to the name than first appears. To my initial joy, my research and gamble paid off, the SFP+ DAC cable installed really nicely into the back of both Rose products with a very tight and secure fit and it worked perfectly. The Rose RS130 server saw the RD160 DAC almost instantly and this link seemed more secure and locked in straight away compared to the Rose branded solution that could be temperamental making the connection initially. I didn’t expect that to have any effect on the sound quality but maybe it had its impossible to say.
As the HiFi Rose branded fibre SFP+ cable was not working I was unable to compare it to the FS.com DAC cable equivalent, however I was able to test it compared to USB. This was quite funnily back to where I started comparing an SFP to USB link between the Rose units but this time the result was totally different. Now the DAC SFP connection sounded louder and more immediate and the big surprise was more tonally substantial compared to USB. USB no longer had the more full bodied sounding advantage. I did not expect there to be so much difference but as much as I liked and preferred the SFP’s sound now music also sounded a little more unruly and edgy compared to USB. With the USB connection there was less, but the music sounded more controlled and composed and after listening between the two for a few hours I still concluded that SFP is the best way to connect both HiFi Rose products together from the two, but I needed to work out what was going on and how to maximise the DAC cables SFP benefit.
Straight away I thought about the quality of the FS.com cable, maybe the much more advanced Tellurium Q USB cable design was shielding more external noise better, but SFP still had a more direct connection within the RD160 DAC leading to the better sound quality differences. I still think this is a possibility so have reached out to Melco’s UK PR company to try and get one of their C1 D20 SFP+ DAC cables to try out. Melco are the only manufacturer I can find who make a “high end” SFP+ DAC cable and they have said yes to sending me one and I am now waiting to receive it. If there is any further improvements to be had I will report back on this in the future once I have had some testing time.
Mistakes realised and tweaks employed
I mentioned before that this SFP exploration has reminded me of getting into vinyl playback and another reason for that is I have been doing things without knowing why or giving them any serious consideration to wether they are the best things to do. One big one has with the HiFi Rose RS130 only having an SFP network connection and if you want to connect to it using a traditional network RJ45 you have to use the included adapter. For all of my testing using RJ45, so all of my comparison testing between SFP and the Network Acoustics Muon Pro streaming system I have been using the included Rose adaptor. Well this week the penny finally dropped, of course this is not an adaptor its a converter from RJ45 to SFP, so very similar to the different SFP modules I have bought and tested and realised don’t all sound the same. How much this convertor has been effecting things sonically I couldn’t say at the moment but I am at least now aware of it and there are two alternatives I am considering purchasing to test this. These will cost around £100 so that purchase has had to wait. Instead I have started testing the SFP DAC cable for networking and so far things seem good sonically but its very early days, but that is not all I am testing.
Network Acoustics have managed to catch up with their outstanding orders and have been able to ship me a Tempus network switch in the silver colour I requested. It’s larger than I expected and the hybrid power supply is different to how I thought it would be too, but its still all very nice and well designed. My very early impressions are positive but I cannot say anything concrete about it for the moment.
One thing I can definitely recommend to HiFi Rose users of either the RS130 or the RD160 DAC is a tweak I have been using for some time now. A few years ago JCAT sent me two of what they call USB Enhancers. At €250 each they are a little more expensive than I remembered, however I have one plugged into both Rose products and find they help make the high frequencies sound a little less sharp and the music a little more pleasing overall. Its not a night and day difference of course but its a tweak I will be doing with these two Rose units going forward. I plug one into any of the three USB sockets of the RS130 but do prefer to use the USB dedicated for audio, that seems a give a slightly better result. To use the USB enhancer with the RD160 I have to use a USB type A to type B adaptor but these are cheap on Amazon.
Final Thoughts
I can imagine this article could be very confusing to some one who is knew to SFP, it would have been to me three months ago and I apologise if that is the case. I have tried to explain things in as simple language as possible but I would suggest reading my previous articles too as hopefully that can help get you get to at least my still basic, but better experienced understanding.
In short, for £19.20 the FS.com SFP+ DAC cable for linking the HiFi Rose products together has been a great buy and I have to thank Tom for his suggestion to explore this area. I don’t think I am finished with this exploration but it would be the connection I would currently recommend as “best” for an all Rose digital front end.
My networking exploration continues and I am currently testing the FS.com SFP DAC cable here too but it has a lot more stiff competition from the Network Acoustics Muon Pro streaming system and fibre options I have here and I will report back my findings for you soon and anything else I discover that could be useful.
