Lumin U1. What does it bring to the table?

I have my library on a Synology NAS and the core on a MacBook Pro which is connected via USB to a Chord Qutest.
I consider the MBP to be the weak link in the chain, being not optimised for audio, so I was looking to replace it.
Initially I was very interested in the Lumin U1, but I have since learned that it can not run Roon core, so I would still need to run the MBP (not interested in running Roon server on the NAS due to performance restraints) and the Lumin D1 would sit between the MBP and the Qutest.
So what improvements in SQ would I get in such a situation? At the moment it seems to me that it would be just another obstacle in the audio chain.

Sounds like you need a Nucleus or NUC to run Roon Core.

I understand. But I’m still puzzled what the role of a product like the U1 is.

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A network streamer and alternative to Roon Core. Broadly equivalent to a Nucleus plus Roon subscription. If you’re running Roon it’s a very expensive Roon Ready transport. No benefit whatsoever in your scenario.

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Thank you for explaining

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None of the current Lumin products run Roon Core.

We have customers who were using MacBook Pro with Chord Dave. Upon using Lumin U1 instead of MacBook Pro, they all reported improvements with sound quality. There are factors that affect sound quality even if the digital bits are the same.

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I am interested in the U1. Is the external power supply a linear power supply? Thanks.

Yes. Lumin U1 comes with an external LPS. The unit itself has a heavy aluminium chassis.

Lumin U1 MINI has an internal SMPS built-in. Its price is much lower.

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Thanks for the quick reply.

I did know the U1 has an external power supply but did not know if it was considered a linear power supply.

Actually I do not know what makes a linear power supply better than a standard power supply, other than it is supposed to be better.

I just purchased the U1 and waiting to receive it.

I read that it upsamples and downsamples. What is the purpose of downsampling?

When playing PCM music, can it be outputted as PCM, or does it automatically have to be converted to DSD?

For USB and AES/EBU, is one sonically better than the other?

Thanks in advance.

For people with older DAC that cannot handle a high sample rate, or a PCM-only DAC that cannot handle DSD. When using Roon, you may leave Lumin built-in re-sampling turned off (default), and perform any such tasks (if necessary) via Roon DSP Engine.

Music is output in a bit perfect manner by default. You may use Roon DSP Engine to upsample PCM to DSD if you want to.

This is setup dependent. I’ve received more users reporting AES sounding better than USB, then the other way round. For DSD, AES output is limited to DoP64, and many DSD DAC do not support DoP from a non-USB input.

Thanks for the quick reply.

I have a dCS Debussy DAC. It is discontinued and had it’s last firmware update in early 2018.
dCS is pleased to announce the release of software version 2.30 for the Debussy Plus USB DAC.

This is from the dCS update:

"The update adds DXD and DSD/128 capability to the USB and Dual AES interfaces, so that files recorded at these rates can be played directly.

The Dual AES interface will also accept dCS-encrypted DSD/64 data from dCS CD/SACD Transports, so the Debussy is now compatible with the Vivaldi Transport, as well as the final versions (v1.11) of the Scarlatti & Paganini Transports when set to “Vivaldi Mode”."

I guess I have to check if it will play DSD over single AES/EBU?

I just read that the AES1 and AES2 inputs can be used individually at 32, 44.1, 48, 88.2, 96, 176.4 or 192kS/s or with DSD/64 in DoP format.

I was told Lumin U1 DoP over AES output to dCS Vivaldi works. So I assume it would work on dCS Debussy too.

Please let me know your results.

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The Vivaldi is a newer and current model and so they may not be capable of the same things.

It looks like maybe only what I typed above your message.

“AES1 and AES2 inputs can be used individually at 32, 44.1, 48, 88.2, 96, 176.4 or 192kS/s or with DSD/64 in DoP format.”

I found out that my unit will arrive in the USA tomorrow and I will have it next week. Can’t wait!

I got my U1 this evening. Even ice cold out of the box I like the sound. How many hours typically for break in?

A couple of questions.

  1. Can I play music from a SSD plugged into one of the USB ports?

  2. Under cumin options, should I leave all of the sample rates at native?

  3. I had heard that the U1 will sound better with the audio outputs turned off that are not being used. I see in the app that there is Optical, Coax BNC, Coax RCA, AES/EBU. What is the USB labeled as? Optical?


I remember a recent customer report said he heard improvements after a few days.

  1. You may play music from a USB flash drive using Lumin app, not Roon. We have not tested USB SSD - if it draws too much power there may be a problem.

  2. Please set re-sampling to Off. Any such needs should be done using Roon DSP Engine.

  3. There is no option to turn off USB audio output. It is automatically detected.

If you don’t use Spotify Connect or AirPlay, please turn off Spotify Connect and Lumin Streaming respectively. (Some customers also turn off the front panel as well.)

Is this working for you?

I’ll have to copy songs to a flash drive then. I had hooked up an SSD and didn’t work.

Noted regarding the re-sampling, USB audio output, and turning off the other items you recommended.

I did listen to AES/EBU but wasn’t listening to DSD. I was surprised that USB was so much more open and dynamic sounding. The difference wasn’t that much when I used the AES/EBU cable from my Mark Levinson CD transport to my DAC versus USB from NUC to the DAC. I wonder why? The AES/EBU cable is a Synergistic Research Galileo and is an excellent cable.

What should I set MQA to? Off, Pass through, or digital out? I don’t think my DAC does MQA. I did play some Tidal that said MQA 29/192 on the front panel though of the U1.


Please set MQA to digital - it should be the default.

I’m glad you find the USB to sound good. This way you can play DSD128.

You may also experiment with Roon DSP upsampling to 352.8kHz for 44.1kHz family music and 384kHz for 48kHz family music, or everything to DSD128. See which sounds better to you.

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Thanks, Peter.

This would normally sound like a dumb question, but then again this is the audio hobby. Is there any certain brand or storage size I should get for the USB flash drive for ripped files? Also where in the Lumin app will the files be shown?