Lumin X1: Enabling an Even Simpler Yet Better Sounding System

[tmallin]

I finally bit the bullet and added an ethernet cable connection to my audio room. Thus, now both my Roon Nucleus Plus and my Lumin X1 are ethernet connected all the way back to my Comcast Advanced Gateway (combination modem/router). This allowed elimination of the TP-Link Wireless N300 2T2R Access Point used in client mode which I was using to provide a wired ethernet connection from a few feet away from the Lumin to the Lumin. The Wi-Fi path length between my router and this TP-Link device was at most 10 feet, straight down through the floor and the ceiling of the room below.

Since my house is circa 1904, it has plaster walls and firestop horizontal 2x4s built into the exterior walls on both the first and second floors of the house. I knew from previous experience of adding dedicated electrical circuits that running cable in this house is not in easy or inexpensive proposition, especially if you don't want to rip out a wall to gain access to the firestop boards to ease vertical passage of cables. And I didn't want an exterior raceway since they are ugly. In 2015 it cost me over $2,000 to add four dedicated circuits, two each in my downstairs living room (where I at first had my Harbeth system) and my current upstairs audio room. For the audio room, the electrical had to be routed from the basement panel up the chimney raceway, up into the attic and then back down into the wall where I wanted the electrical outlets--not a direct path by any means.

So since I moved into the home in 2014 I've lived with Wi-Fi connections to my audio systems. Fortunately given where I placed the router and where my audio room is, the audio room gets very strong Wi-Fi signal. With my Comcast 1 Gig service (that speed is only guaranteed to be approached by a short direct wired connection) I regularly clock W--Fi speeds in excess of 600 Mbytes/sec in my audio room using Ookla's SpeedTest app. And since I've been very pleased with the sound of all the streamers I've had in this room compared to direct CD playback by my old Oppo UDP-205, I didn't think I was missing much, if any, potential further quality.

As expected, adding the ethernet connection to my audio room was neither easy nor inexpensive. The job cost $1,000, involved eight solid hours from an extremely hard working technician, and well over 100 feet of cable to go that 10-foot distance. The ethernet cable had to be routed down to the basement from the existing cable TV wall box, along the basement ceiling, up the drain flue to the attic, across the attic space and then back down that same wall where I had the electrical outlets installed, into an existing unused cable TV outlet box. Even with fiber-optic camera assistance it took the installer a good four hours to fish the cable from the attic through the small existing hole in the firestop board (put there long ago by a previous owner when the cable TV or attic antenna was installed, I suppose). There was insulation in the way since this wall was originally the exterior wall of the house before the first of several remodeling/addition projects undertaken by prior owners. This insulation impeded the progress of the fishing job enormously. The only small damage done was a slight plaster crack off near the outlet box in the audio room. The installer fixed that with a bit of spackling compound and all I have to do to finalize that repair is apply a bit of matching paint to that area. I still have the original paint can and formula so I can get a fresh pint of matching paint, so that shouldn't be too hard to fix.

Given the anticipated circuitous path of the cable pull, I decided on an enhanced version of CAT 6 cable, one with an overall shield braid which adds strength to the cable without adding too much stiffness. Its a verified rated cable, rated for 550 MBpsec. Sure, this is a far cry from the rating of the newest CAT 8 cables. But CAT 8 cables--good ones, at least--tend to be thick and stiff, not good for the type of cable routing I anticipated.

And since this cable is for audio only, the CAT 6 rating is entirely adequate. Even DSD 512 rates at something less than 23 MBpsec are still quite slow compared to such a cable's data transmission capability. And as far as my library and streaming goes, unless I'm resampling, even 24/192 PCM material has a transmission rate of only 192 KBpsec, practically motionless compared to the cable's rating.

So now I finally have that ethernet connection to my audio room. Was it worth the trouble and expense? I can honestly say "yes!" Despite the quality of the Wi-Fi signal I had, either the elimination of the TP-Link device, the hardwiring of everything, or a combination of those factors, eliminates a bit of high frequency grunge, blackens the background, deepens the depth of field, further stabilizes the images, and just generally provides a more "relaxed" sounding presentation. I would also say that the elements of PRAT are somehow improved. This is despite the length of ethernet cable needed make the connection.

Is this a subtle sonic change? Perhaps. I don't think it's something which would be obvious at first hearing to most people. The frequency response seems basically unchanged. But, to my ears at least, it is the type of change which makes an important difference in the subjective quality of the presentation. It might be difficult to measure, but there is a new "rightness" to the sound which is disarming. Was it worth $1,000? To me, yes, certainly, but that may be because of the much larger sunk cost I have invested in the many changes and upgrades needed to get my system to its current performance level.

I noticed the same sort of sonic changes in my prior home when I switched from Wi-Fi to ethernet connections. But that was back in the "early days" of Wi-Fi and streaming and I didn't really know what to expect with more modern equipment. Back then, my streamer of choice was a Logitech Squeezebox Touch--not a bad-sounding unit at all, really. I still use one in my audio system in our commercial office building, along with a pair of vintage AR-4x speakers.

Lumin recommends a wired ethernet connection and does not include any built-in Wi-Fi capability in its products. Most high-end streamer companies, other than Auralic, recommend ethernet connections even if they do include native Wi-Fi capability.

 

[Empirical Audio]

Such a long Ethernet run should get an audiophile switch at the end, like the SOtM. And then a good Ethernet cable like the SOtM to your component.

 

[tmallin]

Since I only have one cable coming into the room and will soon have three components in the room needing ethernet connection, yes, I soon will need an ethernet switch. As far as switch and cable quality goes, I'll start with an ordinary TP Link 5-port switch, an iFi power supply for it, and Blue Jeans Cable Cat 6 individually tested and verified ethernet cables. I can always "upgrade" to "audiophile" quality later. Half the fun is getting there.

Further listening (plus perhaps break in of the new ethernet cable and further warm up of the equipment which had all been turned off for a day while this job was being done) indicates that the elimination of that single 10-foot wireless link in my signal chain has made a substantial improvement in the sound quality. I wish I'd done it sooner, but, again, half the fun is getting there.

 

[tmallin]

Now that I've switched to the Dutch & Dutch 8c speakers, I need three ethernet cable connections in my audio room. Thus the need for an ethernet switch in this room. One ethernet cable is needed for my Lumin X1 streamer and one for each of the D&D speakers.

It also occurred to me that now that I had ethernet in this this room, I could also move my Roon Nucleus+ and the Keces P8 linear power supply for it to my audio room. Until now, they had been in my dining room immediately below my audio room, where the Nucleus+ could be attached via a short ethernet cable to my Xfinity Advanced Gateway modem/router. That router is in a great spot for supplying strong Wi-Fi signal throughout my old plaster-walled two-story house. I had tucked the Nucleus+ and its power supply under a hutch where they were out of the way of foot traffic. The router sits on the floor under a stationary stool right next to the hutch--I'm not sure why that location works so well for Wi-Fi in my home, but so it does.

I did not want to also move the router to the audio room for three reasons. First, the router has a fan which operates most of the time and thus would be audible during quiet passages of music. Second, I would have to route a cable connection to the audio room in addition to the ethernet connection and didn't want to incur the expense for that, given the $1,000 I just spent to get the ethernet connection to this room. Third, putting the router in this room probably would not give me the great Wi-Fi coverage I currently have in the house, necessitating some sort of mesh router system. Most of those (if not all) do not have the Wi-Fi bandwidth I currently get from my Xfinity router with Gigabit service. Even with Wi-Fi I regularly clock speeds of 600 mbps and above in my audio room. Most mesh systems are only rated for 100 to 200 mbps.

The advantage of moving the Roon Nucleus+ and its Keces P8 power supply to the audio room is that I could take advantage of the vibration isolation and purer powerlines available in the audio room, courtesy of my Salmander Archetype rack, A/V Room Service EVP isolation feet, the dedicated power lines, and P.I. Audio Group outlets and UberBusses in this room.

I also thought I'd take this opportunity to try out the fiber optical connection my Lumin X1 offers in place of the copper ethernet connection I'd been using. This type of wired connection is explained on the Lumin website at this fibre networking page. This required swapping out my TP Link gigabit switch for a switch with an SFP slot. Since I know little about fibre networking and did not want to have to learn how to troubleshoot such network connections, I followed Lumin's instructions to the letter, figuring that they know what fibre networking equipment works with their Lumin X1.

Thus, going by the recommendations on the Lumin Fibre Networking page I purchased the recommended Cisco switch (about $170 through Amazon), plus two of the 10GTek single-mode 1310nm SFP modules (about $40 from Amazon), plus a one-meter fibre optic cable from FS (about $10), for a total investment of about $220 to move from a copper ethernet connection between the Cisco switch and the Lumin X1 to a fibre optic ethernet connection between those two components.

I moved the outboard Lumin X1 linear power supply up to the top shelf of my three-shelf Salamander rack alongside the main chassis. I mounted the Roon Nucleus+ and its Keces P8 outboard linear power supply side by side on the middle shelf. I mounted the Cisco switch atop the two P.I. Audio Group UberBusses on the lower shelf. Each piece of equipment is mounted atop four A/V Room Service EVP (Equipment Vibration Protectors) of the proper weight rating for each component. All equipment, including the D&D 8c speakers, is plugged into the UburBusses.

Here's a picture of this new set up:



Note that if you want to try the fibre optic connection with the Lumin X1, I recommend that under options in the Lumin App you first select that the Network LED be on. I had it off before. While I don't know for sure, I think this is necessary for the fibre optic network connection. I did not call Lumin about this and can't find any online discussion about that option, but it makes sense that the option refers to enabling the fibre optic networking option. It does not refer to anything visible on the Lumin X1's screen display since the display stays the same with that option on or off.

Also note that the instructions for installing the SFP modules stress that these are static sensitive devices. In other words, you are advised to wear a wrist strap grounding device when working with these. I attached the grounding cable of mine to the ground screw on the back of my Lumin X1 and had no mishaps. There were no instructions supplied as to how to attach the two "wires" of the fibre optic cable to the modules or which side is "up" when you insert the modules. I saw what I thought was color coding (white and yellow) on both the cable and modules, but when I tried to match up these color codings the cable would not fit into the modules. I went with the way everything physically went together easily and got a reassuring click when the fibre cables mated with the modules. Similarly, the modules would only physically insert into the ports in one orientation, so that was decided for me. I "got sound" immediately the first time I hooked up the new connections with no "network error" messages.

So, how does it sound compared to the previous ethernet connections? More marvelous!

This system was already marvelous in sound, the best by far I've had in this room. But the combination of better vibration protection, purer powerlines, and the fibre optic connection between the switch and the Lumin moves the performance up to a level of naturalness and a freedom from distortion which I had to hear to believe. There is simultaneously an increased smoothness and transparency to the sound without any real detail being lost. What is lost is distortion which was adding just a bit of edge that was not really noticed until I heard its absence.

I did A/B the Lumin with a copper ethernet link, then with the optical link. That change in itself is a significant part of the transformation I'm hearing.

Changing from copper ethernet to the fibre optic connection between the switch and the Lumin X1 meant even less "grunge" in the background, blacker backgrounds, even less high frequency digital nasties, and a generally more open sound. This is true regardless of the quality of the program--it applies from low-bit-rate internet radio up through high-res programs from Tidal or Qobuz. Lumin and the reviewers who have commented on this type of connection's performance are correct. This is better yet than an ethernet connection, which itself was better than a single Wi-Fi link in the streaming connection.

I can heartily recommend that those of you who have a Lumin X1 (or another streamer with a fibre connection potential built in--are there any others?) try this right away. The money spent, at least in my system, was way out of proportion to the audible improvement. What was obviously already a top streamer before in terms of sound quality is now at another level entirely, qualitatively superior to anything I've previously heard in network streaming.

 

[chungjh]

I currently have U1 mini > Lampizator Big 7 DAC >Don Sachs 2 tube preamp >Pass labs X250.5 > Sound lab speakers. I was thinking of upgrading to U1 mini+Keces P8, but I hear that the full U1 is much better than U1M+LPS. Then, I read your blog and hear so many good things about X1, but it is very very expensive. So, I was thinking of selling my tube preamp to make up for the cost since X1 has digital preamp. Then I heard about all the loud volume issues when playing X1 without an analogue preamp. This discouraged me because I know my wife, who is not electronic savvy, will get startled with the sound level. Is there a idiot-proof way of preventing the blasting volume problem? Also, do you think the digital volume control on X1 is good enough to take the place of a very good preamp? I would love to hear your inputs on all these questions as it will decide what I buy.

 

[chungjh]

Oh, one more thing. I guess if I go with X1, I don't have to worry about all the potential for interference from all the interconnections that I would need compared to U1>Lampizator DAC>preamp>Pass Labs amp.

 

[tmallin]

In Post #1 of this thread I explain how the sound of the digital volume control in the Lumin X1 bested the sound of controlling my system volume via the Benchmark HPA4. The HPA4 was the best volume control/preamp I'd ever experienced until the Lumin X1. I do not agree that any tube-based preamp is at the Benchmark's level of clarity, lack of distortion, etc. That's just not the way I hear it.

Anyway, despite how good the Benchmark sounded controlling my system volume, it was soon quite clear that the digital volume control of the Lumin X1 bested it directly controlling my Benchmark ABH2 amps.

And that was long before Lumin incorporated the Leedh DSP volume control, see post 35 and 36 above. I feel confident in saying that the X1's volume control is certainly better sounding than whatever you've been using before. Far better.

To get the full benefit of the Lumin X1, you must also be sure to use ethernet connections to the Lumin. Better yet, as I discuss in post 44 above, use a switch and go with a fiber optic connection between the switch and the Lumin X1.

As far as volume blasting when connecting the X1 directly to the amps, this is only a problem if you are using an internet radio source that is coming in via AirPlay from your control device, like an iPad. For any source "native" to the Lumin app (Roon, Qobuz, Tidal, Spotify, any Tune-In radio station, and all your local music files) there is never a problem with volume control. It is only for sources like Sirius/XM, Jazz Radio, and other internet radio sources you can't get through Tune-In that there is a potential problem.

I think I explain this issue about as well as it can be explained in Post #3 above. But since I wrote that, Lumin has made a firmware change which could ameliorate this potential problem. You can now set the variable volume control to max out at less than 100% so that the maximum volume blast can be lessened. Of course then you'd either have to be satisfied with that maximum volume level or go into the options and switch the max volume to a higher level--a few touches on the iPad.

Yes, if you use the X1 from its analog output you would be eliminating some wiring connections since you'd no longer need your preamp or your Lampizator. That's why "Simpler" is in the title of this thread.

The X1's DAC is excellent. I would not say it any better than the Benchmark DAC3 HGC I was using before. The Benchmark DAC is definitely a bit clearer, more detailed, and has yet lower noise, but the Lumin is a bit less edgy and bright. Not that the Benchmark is bright, but the Lumin is definitely in the "smooth" sounding camp without losing any appreciable real detail that matters musically.

Also, the Lumin X1, used via its balanced analog outputs is the first DAC that I thought really makes MQA recordings on Tidal competitive with Hi-Res PCM on Qobuz of the same material. Not that MQA now sounds the same as the Qobuz Hi-Res, but MQA now has pluses which make it truly competitive despite its minuses. Prior MQA renderings I've heard just weren't in the same league as true Hi-Res from Qobuz.

 

[lscangus]

I currently have U1 mini > Lampizator Big 7 DAC >Don Sachs 2 tube preamp >Pass labs X250.5 > Sound lab speakers. I was thinking of upgrading to U1 mini+Keces P8, but I hear that the full U1 is much better than U1M+LPS. Then, I read your blog and hear so many good things about X1, but it is very very expensive. So, I was thinking of selling my tube preamp to make up for the cost since X1 has digital preamp. Then I heard about all the loud volume issues when playing X1 without an analogue preamp. This discouraged me because I know my wife, who is not electronic savvy, will get startled with the sound level. Is there a idiot-proof way of preventing the blasting volume problem? Also, do you think the digital volume control on X1 is good enough to take the place of a very good preamp? I would love to hear your inputs on all these questions as it will decide what I buy.

A preamp is more than just a volume control. I think is best for you to try it with your system with or without the preamp.

 

[tmallin]

I agree that it is always better to get a loaner first and try it both ways. If you can get a loaner X1 before committing to purchase, by all means do that. But that is not always possible since many Lumin dealers don't have an X1 available for loan.

One thing you should keep in mind is that Lumin's own factory reference system is set up with the Lumin X1 directly driving the Lumin Amp with no intermediary preamp. Another thing to note is that the X1's normal output through its balanced analog outputs is 6 volts. In the low output mode it is 4 volts. Either way, this is plenty of output voltage to drive most amps to and beyond their rated output. Check the specs on your amp, but most X-series Pass amps seem to have the "normal" amount of gain of 26 dB, which is a lot, allowing driving the amp to full output with a mere one or two volts of input. Thus, no preamp is needed to increase the available input voltage to the amp from the Lumin X1.

You say, "A preamp is more than just a volume control" as if that statement is self evident. Well, yes, it's a source selector. But with a digital streaming system where all the sources can be selected by the Lumin X1, there is no additional source selector needed. Yes, for a system with analog sources like a turntable or reel-to-reel tape deck, you would need an analog preamp to select those sources and provide any special preamp gain and EQ functions, such as the RIAA phono EQ and a ton of gain to increase the millivolt or microvolt output of the cartridge to the line level of at least a volt or two. But if you don't have such analog sources, you don't need a preamp for additional gain or source selection.

So what else does a preamp do? In some cases it can act as an impedance matcher. Some devices have rather high output impedance and a good solid-state (NOT tube) preamp will have a very low output impedance of 10 ohms or less so that regardless of how low the input impedance of the amp is, the source can drive it to full rated output with no overload, low distortion, and no unintended frequency response coloration. For example, some high-end amps have a 600 ohm input impedance and are highly reliant on low very output impedance sources to avoid response colorations and avoid overloading the source's output with resulting distortion. But the Lumin X1 already has a low output impedance and plenty of voltage drive for most amps like the Pass models. And take a look at the X1's outboard power supply--it's quite a design.

In addition, tube preamps usually have a high-ish output impedance and cannot be relied upon to drive an amp any better than the Lumin X1. Many people apparently like what they hear from tube preamps, but this is usually the result of frequency response colorations due to the interaction of their high output impedance with amps which have low-ish input impedances. Use a tube preamp with an amp with a megaohm input impedance to hear what a tube preamp really sounds like. Even so, the distortion and noise figures of tube preamps are usually 10 or 20 dB worse than those of solid-state preamps.

So what do you really usually get from a preamp, especially a tube preamp? Added distortion and noise from additional unneeded active circuitry, cables, and connections. Frequency response colorations from impedance mismatches with amps. You may like the way it sounds--many people like added second harmonic distortion, for example, since it tends to "sweeten" the sound. But it is usually just added coloration. And the analog volume pots of most preamps just aren't remotely in the same league as the Leedh DSP volume control available through the X1 (and all Lumin streamers, for that matter). Most analog volume controls have rather obvious channel tracking problems at low levels so that the left/right balance changes with changes of the volume control.

Some preamps are advertised as "passive." This can mean that there is no active output stage and/or no buffering. Extreme examples of such units don't even need to be plugged into AC power. The old Mod Squad Line Drive was one of the first such designs. (Decades ago I owned two different versions of this device and even modified them for "better sound.") These are at the mercy of the volume pot used, the capacitance of the downstream connecting cable, and the input impedance of the downstream amp. The output impedance of such a unit will vary with the setting of the volume control. The cables on its output must be kept very short and must be low capacitance to avoid rolling off the bass. The variable output impedance with volume setting will make the unit a true chameleon in some systems. Despite these problems some audiophiles still view such units as a "holy grail" of preamps.

For a great discussion of the importance of system volume control, and the strengths and weaknesses of various designs, see Benchmark's discussion here.

I'm not saying that preamps cannot perform well. It's just that in the context of a system for which the Lumin X1 provides all the sources you need, the preamp is superfluous and can only degrade the sound, however slightly. For a contrast of how well solid-state line-level preamps can perform compared to tubed preamps, see Stereophile's measurements of the Audio Research LS5 MkII (solid state) here and the PrimaLuna EVO 400 preamp (tubed) here.

 

[José luis]

 

[José luis]

agregar un melco s100 en el kit da una gran actualización al x1

 

[chungjh]

Has anyone tried to insert 10 MHz master clock (e.g. Mutec REF10) upstream of X1. Would you expect a noticeable improvement in SQ?

 

[chungjh]

Now that I've switched to the Dutch & Dutch 8c speakers, I need three ethernet cable connections in my audio room. Thus the need for an ethernet switch in this room. One ethernet cable is needed for my Lumin X1 streamer and one for each of the D&D speakers.

It also occurred to me that now that I had ethernet in this this room, I could also move my Roon Nucleus+ and the Keces P8 linear power supply for it to my audio room. Until now, they had been in my dining room immediately below my audio room, where the Nucleus+ could be attached via a short ethernet cable to my Xfinity Advanced Gateway modem/router. That router is in a great spot for supplying strong Wi-Fi signal throughout my old plaster-walled two-story house. I had tucked the Nucleus+ and its power supply under a hutch where they were out of the way of foot traffic. The router sits on the floor under a stationary stool right next to the hutch--I'm not sure why that location works so well for Wi-Fi in my home, but so it does.

I did not want to also move the router to the audio room for three reasons. First, the router has a fan which operates most of the time and thus would be audible during quiet passages of music. Second, I would have to route a cable connection to the audio room in addition to the ethernet connection and didn't want to incur the expense for that, given the $1,000 I just spent to get the ethernet connection to this room. Third, putting the router in this room probably would not give me the great Wi-Fi coverage I currently have in the house, necessitating some sort of mesh router system. Most of those (if not all) do not have the Wi-Fi bandwidth I currently get from my Xfinity router with Gigabit service. Even with Wi-Fi I regularly clock speeds of 600 mbps and above in my audio room. Most mesh systems are only rated for 100 to 200 mbps.

The advantage of moving the Roon Nucleus+ and its Keces P8 power supply to the audio room is that I could take advantage of the vibration isolation and purer powerlines available in the audio room, courtesy of my Salmander Archetype rack, A/V Room Service EVP isolation feet, the dedicated power lines, and P.I. Audio Group outlets and UberBusses in this room.

I also thought I'd take this opportunity to try out the fiber optical connection my Lumin X1 offers in place of the copper ethernet connection I'd been using. This type of wired connection is explained on the Lumin website at this fibre networking page. This required swapping out my TP Link gigabit switch for a switch with an SFP slot. Since I know little about fibre networking and did not want to have to learn how to troubleshoot such network connections, I followed Lumin's instructions to the letter, figuring that they know what fibre networking equipment works with their Lumin X1.

Thus, going by the recommendations on the Lumin Fibre Networking page I purchased the recommended Cisco switch (about $170 through Amazon), plus two of the 10GTek single-mode 1310nm SFP modules (about $40 from Amazon), plus a one-meter fibre optic cable from FS (about $10), for a total investment of about $220 to move from a copper ethernet connection between the Cisco switch and the Lumin X1 to a fibre optic ethernet connection between those two components.

I moved the outboard Lumin X1 linear power supply up to the top shelf of my three-shelf Salamander rack alongside the main chassis. I mounted the Roon Nucleus+ and its Keces P8 outboard linear power supply side by side on the middle shelf. I mounted the Cisco switch atop the two P.I. Audio Group UberBusses on the lower shelf. Each piece of equipment is mounted atop four A/V Room Service EVP (Equipment Vibration Protectors) of the proper weight rating for each component. All equipment, including the D&D 8c speakers, is plugged into the UburBusses.

Here's a picture of this new set up:

View attachment 68809

Note that if you want to try the fibre optic connection with the Lumin X1, I recommend that under options in the Lumin App you first select that the Network LED be on. I had it off before. While I don't know for sure, I think this is necessary for the fibre optic network connection. I did not call Lumin about this and can't find any online discussion about that option, but it makes sense that the option refers to enabling the fibre optic networking option. It does not refer to anything visible on the Lumin X1's screen display since the display stays the same with that option on or off.

Also note that the instructions for installing the SFP modules stress that these are static sensitive devices. In other words, you are advised to wear a wrist strap grounding device when working with these. I attached the grounding cable of mine to the ground screw on the back of my Lumin X1 and had no mishaps. There were no instructions supplied as to how to attach the two "wires" of the fibre optic cable to the modules or which side is "up" when you insert the modules. I saw what I thought was color coding (white and yellow) on both the cable and modules, but when I tried to match up these color codings the cable would not fit into the modules. I went with the way everything physically went together easily and got a reassuring click when the fibre cables mated with the modules. Similarly, the modules would only physically insert into the ports in one orientation, so that was decided for me. I "got sound" immediately the first time I hooked up the new connections with no "network error" messages.

So, how does it sound compared to the previous ethernet connections? More marvelous!

This system was already marvelous in sound, the best by far I've had in this room. But the combination of better vibration protection, purer powerlines, and the fibre optic connection between the switch and the Lumin moves the performance up to a level of naturalness and a freedom from distortion which I had to hear to believe. There is simultaneously an increased smoothness and transparency to the sound without any real detail being lost. What is lost is distortion which was adding just a bit of edge that was not really noticed until I heard its absence.

I did A/B the Lumin with a copper ethernet link, then with the optical link. That change in itself is a significant part of the transformation I'm hearing.

Changing from copper ethernet to the fibre optic connection between the switch and the Lumin X1 meant even less "grunge" in the background, blacker backgrounds, even less high frequency digital nasties, and a generally more open sound. This is true regardless of the quality of the program--it applies from low-bit-rate internet radio up through high-res programs from Tidal or Qobuz. Lumin and the reviewers who have commented on this type of connection's performance are correct. This is better yet than an ethernet connection, which itself was better than a single Wi-Fi link in the streaming connection.

I can heartily recommend that those of you who have a Lumin X1 (or another streamer with a fibre connection potential built in--are there any others?) try this right away. The money spent, at least in my system, was way out of proportion to the audible improvement. What was obviously already a top streamer before in terms of sound quality is now at another level entirely, qualitatively superior to anything I've previously heard in network streaming.

 

[chungjh]

tmallin

A number of X1 users seem to use EVPs to minimize vibration. How do EVPs compare with other vibration isolators such as IsoAcoustics, which are comparably priced?

 

[AMR / iFi audio]

Thanks again for your detailed report. I was considering upgrading my system by connecting it with the Ethernet cable, and I am wondering, which CAT to go for.

The difference between CAT5 all the way to CAT8 is significant. The data transfer is apparently 250 to 400 times faster. CAT6's capability is sufficient to pass DSD 512, but the shielding plays a vital role as well. Cat7 and up tend to use gold plates for shielding. I am really allergic to even the slightest interference, so I am considering getting a cable with S/FTP or SF/FTP - reduces crosstalk even further. Any advice or update since the last report?

 

[chungjh]

I listened more late last night, after I wrote that prior post. Even at extremely low volume levels (didn't want to wake my sleeping spouse, of course!) of between 8 to 10 on the 100-point volume scale ("normal" high volume for me in this system is about 72 or so), the added clarity and transparency were amazing. It's like I suddenly had Quad 57s or some other speaker known for extreme transparency even at very low volume levels.

The Leedh volume processing can be toggled on and off at will within the Lumin App for comparison. The switchover takes less than five seconds. Thus, pretty good A/B testing of the Leedh processing is available. (This assumes, of course, that Lumin has not somehow "dumbed down" the volume control when Leedh is not engaged in the new firmware. There's no way to quickly A/B the new version of the firmware with the old version.) The difference is the proverbial "night and day." And this is even though the direct connection before seemed surprisingly sonically purer than using the special relay-controlled volume control of my Benchmark HPA4 "preamp" which I thought was pretty special indeed at the time.

If you are using Roon Nucleus+, are you not using X1 streamer function? Nucleus is a streamer too, correct?
I have been trying to like the volume control on Leedh, but I like to skip around different albums and different tracks, which means I have to constantly adjust the volume level via Leedh. This is very cumbersome since VC is not visible until: settings>option>scroll>and then adjust. I would prefer not to use my preamp for SQ reasons as tmallin recommends but I would like to be able to change volume quickly. Any suggestions?

 

[tmallin]

The Lumin X1 (and other Lumin streamers) is a Roon Ready device. In the Lumin App settings, I just turn on the Roon Ready function. With that activated, and Roon set up to allow the Lumin (rather than Roon itself) to control the volume, the Leedh volume control is available to control the system volume directly from either the Lumin App screen or Roon screen. It couldn't be easier. In Roon, you can see in the signal path window that DSP Volume is being applied within the Lumin.

In my current set up, I do not use the Lumin DAC, but use the Lumin X1 as a streaming transport, sending digital signal to the DACs in my Dutch & Dutch 8c speakers.

 

[tmallin]

As discussed above, I'm no longer relying on Wi-Fi for streaming in my audio room. I still use the Comcast/Xfinity Advanced Gateway, but connect to it via about 100 feet of shielded ethernet cable to my audio room. See My Current Audio Systems thread for my current system description.

Just before my streamer I was eliminating noise on this lengthy ethernet line by using a fiber optic connection from my Cisco switch to my Lumin X1 streamer exactly as Lumin recommends at Lumin's Fiber Networking page.

But a few days ago I pulled out that fiber optic link and substituted the GigaFOILv4 Inline Ethernet Filter discussed in this thread on the AudioShark forum. I'll be writing more about the GigaFOIL once I get a "proper" LPS for it. Right now I'm powering the GigaFOIL from an iFi SMPS instead of its stock SMPS. Just yesterday I swapped out the Cisco switch with the fiber optic ports for a Netgear Nighthawk S8000 low-latency managed switch aimed at gamers which I just won in an eBay auction.

That new switch allows me to put the internet connections to my Dutch & Dutch 8c speakers on a low priority with connections to the Lumin X1 streamer, Roon Nucleus+, and my Advanced Gateway at critical priority. I have on order a Keces P3 LPS to power the Netgear switch and the GigaFOIL. I already use the Keces P8 LPS to power my Nucleus+. I also have aftermarket DC cables from Gotham Audio on order from Ghent Audio.

It's early yet, but for those who may find the Lumin-recommended fiber network connections a bit too smooth and laid back, this new combination of the GigaFOIL and Netgear Nighthawk S8000 switch may be just the ticket.

The audible difference between the Cisco and Netgear switch is especially startling and all in favor of the Netgear. I thought the subjective comments about the sonic qualities of this switch quoted in Archimago's blog must have been a joke--until I heard this switch in my system. While I still think the description of the positive sonic qualities of the switch found in Archimago's blog are audiophile exaggeration, they are all in the direction of change I hear and the change is not subtle. The TP Link switch and Cisco switch sounded similar to each other in my system; the Netgear Nighthawk switch is a significant improvement.

 

[lscangus]

I agree that it is always better to get a loaner first and try it both ways. If you can get a loaner X1 before committing to purchase, by all means do that. But that is not always possible since many Lumin dealers don't have an X1 available for loan.

One thing you should keep in mind is that Lumin's own factory reference system is set up with the Lumin X1 directly driving the Lumin Amp with no intermediary preamp. Another thing to note is that the X1's normal output through its balanced analog outputs is 6 volts. In the low output mode it is 4 volts. Either way, this is plenty of output voltage to drive most amps to and beyond their rated output. Check the specs on your amp, but most X-series Pass amps seem to have the "normal" amount of gain of 26 dB, which is a lot, allowing driving the amp to full output with a mere one or two volts of input. Thus, no preamp is needed to increase the available input voltage to the amp from the Lumin X1.

You say, "A preamp is more than just a volume control" as if that statement is self evident. Well, yes, it's a source selector. But with a digital streaming system where all the sources can be selected by the Lumin X1, there is no additional source selector needed. Yes, for a system with analog sources like a turntable or reel-to-reel tape deck, you would need an analog preamp to select those sources and provide any special preamp gain and EQ functions, such as the RIAA phono EQ and a ton of gain to increase the millivolt or microvolt output of the cartridge to the line level of at least a volt or two. But if you don't have such analog sources, you don't need a preamp for additional gain or source selection.

So what else does a preamp do? In some cases it can act as an impedance matcher. Some devices have rather high output impedance and a good solid-state (NOT tube) preamp will have a very low output impedance of 10 ohms or less so that regardless of how low the input impedance of the amp is, the source can drive it to full rated output with no overload, low distortion, and no unintended frequency response coloration. For example, some high-end amps have a 600 ohm input impedance and are highly reliant on low very output impedance sources to avoid response colorations and avoid overloading the source's output with resulting distortion. But the Lumin X1 already has a low output impedance and plenty of voltage drive for most amps like the Pass models. And take a look at the X1's outboard power supply--it's quite a design.

In addition, tube preamps usually have a high-ish output impedance and cannot be relied upon to drive an amp any better than the Lumin X1. Many people apparently like what they hear from tube preamps, but this is usually the result of frequency response colorations due to the interaction of their high output impedance with amps which have low-ish input impedances. Use a tube preamp with an amp with a megaohm input impedance to hear what a tube preamp really sounds like. Even so, the distortion and noise figures of tube preamps are usually 10 or 20 dB worse than those of solid-state preamps.

So what do you really usually get from a preamp, especially a tube preamp? Added distortion and noise from additional unneeded active circuitry, cables, and connections. Frequency response colorations from impedance mismatches with amps. You may like the way it sounds--many people like added second harmonic distortion, for example, since it tends to "sweeten" the sound. But it is usually just added coloration. And the analog volume pots of most preamps just aren't remotely in the same league as the Leedh DSP volume control available through the X1 (and all Lumin streamers, for that matter). Most analog volume controls have rather obvious channel tracking problems at low levels so that the left/right balance changes with changes of the volume control.

Some preamps are advertised as "passive." This can mean that there is no active output stage and/or no buffering. Extreme examples of such units don't even need to be plugged into AC power. The old Mod Squad Line Drive was one of the first such designs. (Decades ago I owned two different versions of this device and even modified them for "better sound.") These are at the mercy of the volume pot used, the capacitance of the downstream connecting cable, and the input impedance of the downstream amp. The output impedance of such a unit will vary with the setting of the volume control. The cables on its output must be kept very short and must be low capacitance to avoid rolling off the bass. The variable output impedance with volume setting will make the unit a true chameleon in some systems. Despite these problems some audiophiles still view such units as a "holy grail" of preamps.

For a great discussion of the importance of system volume control, and the strengths and weaknesses of various designs, see Benchmark's discussion here.

I'm not saying that preamps cannot perform well. It's just that in the context of a system for which the Lumin X1 provides all the sources you need, the preamp is superfluous and can only degrade the sound, however slightly. For a contrast of how well solid-state line-level preamps can perform compared to tubed preamps, see Stereophile's measurements of the Audio Research LS5 MkII (solid state) here and the PrimaLuna EVO 400 preamp (tubed) here.

There are limitations for both digital and analogue volume control. Is a give or take kind of thing.

 

[wbass]

@tmallin How many steps in the volume control are there? Is it 0 to 100 in steps of 1? How much usable range do you have before it gets too loud?

I've messed around with using a lowlier streamer--the Bluesound Node 2--as a volume control, but I really only have four to six steps in usable range. It's not very granular. So, if the Lumin has the range of an analog volume control, that's very interesting to me. Thanks!