Upgrade Your Lumin! A Step-by-Step Guide

How to add an Sbooster power-supply to your Lumin U1 MINI, D2, or T2

The one-box Lumins contain a high-quality switch-mode power supply (SMPS) that’s well-shielded and efficient. As you move up the Lumin line, you see external power supply units based on toroidal transformers. This offers a number of improvements:

1) It moves the electrically noisy power-supply circuitry away from the streamer and DAC circuits that carry delicate signal information. 

2) SMPS's produce high-frequency switching noise. Some audio manufacturers filter this noise before it enters the component, but it can still affect other components in the system. 

3) A toroidal transformer offers low impedance to dynamic current devices, such as the output stage of DAC circuits, allowing them to draw lots of power very quickly when required by music transients.

Note: The generic or laboratory LPSUs used by many audiophiles can improve some areas, but cause problems in others*. The Sbooster is a filtered, low impedance, full-bandwidth power supply that’s fully optimized for audio by ensuring its performance is linear across and beyond the audio band.

*Many non-filtered linear power supplies improve bass extension because of their bigger transformers, cloud the “air” frequencies, mask micro-detail, and ruin the flow of the music. 

What improvements can you expect?

A properly matched power-supply upgrade to any component improves every aspect of the presentation. Here’s what you can expect:

1) A smoothing over of graininess to the sound that you didn’t even know was there until it went away. 

2) Improved bass extension--the sound will go noticeably deeper, but stay tight. It often gets more textured and detailed.

3) Improved dynamics--drums will have more snap, plucked strings more bite. 

4) More “meat on the bones”. You get better texture and a fuller sound. 

5) Better separation. Voices and instruments seem to occupy their space more realistically, not seeming to bleed into each other, especially during complex passages. 

6) More air, ease, and flow. A greater sense of the recording space, a better connection to the emotion of the music, a greater sense of the motivation, and even physical movement, of the musicians. 

Remember--every product is a constellation of compromises allowing it to be built to a price point. Even great products can be upgraded! 

Here’s the original Lumin PSU:

And here's what you'll be replacing it with:

Sboostering Your Lumin

The Lumin Connection Kit

Unlike say, a Mytek Brooklyn, Lumins don't come with a separate DC input as well as the AC IEC input. So you need to remove the IEC connector and replace it with the plate that has the proprietary two pin connector used by Sbooster. The kit also comes with basic tools and an instruction booklet with, frankly, really hard-to-see black and white photos. Hence this guide.

Lumin T2 Instructions

The photos here show the procedure on a Lumin D2 which, for the purposes of this guide, is identical to the U1 MINI. The T2 uses a slightly different method, and is easier to upgrade than the D2. Fewer screws have to be removed, and there's a lot more room inside to maneuver.

Below, the rear panel of the Lumin T2. To remove the top cover, unscrew only the three Torx screws outlined in red. The cover is held to the face-plate by two rubber-covered clamps. They hold tight, so cover needs to be pulled straight backwards with some force to dislodge them.

Step 1: Gather All the Tools

The Sbooster Lumin Connection Kit comes with a small box wrench, and a jeweler’s T10 Torx driver. The wrench works well, but we advise using a larger, sturdier Torx driver because the screws holding the Lumin PSU are pretty tight. The Philips screwdriver is to disconnect the wires from the Lumin PSU. There’s one wire (leading from the switch to the IEC connector) that needs to be cut, hence the cutter.

Step 2: Remove the Top Cover

There are eight Torx screws holding the top of the Lumin D2 in place. (The T2 has only three screws at the back, as noted above.) Remove these, slide the top of the unit back, and lift it off. 

Step 3: Remove the PSU

There are six screws holding the PSU in place. Take care with these--they are tight, so use a larger Torx driver and press down so it doesn't slip. Holding the PSU in place as you remove the screws will make this easier. The T2 has more room, so removing the PSU screws in an earlier step is okay. On the D2, you run the risk of the loose PSU making it hard to remove the top.

Step 4: Disconnect the Board Connector

The stock-PSU output cable (with yellow and black wires) clips onto the Lumin motherboard in the same way for the D2 and T2. Press the clip and pull upwards with a slow, steady force. It’s tight, but keep up the pressure, and it will come off. 

Step 5: Remove the PSU Cover

The outer shield of the stock PSU has a lip that needs to be worked around the circuit board. This step is much easier on the T2. Notice Lumin’s attention to detail. Not only is the PSU under a metal cover, there’s a cage shield underneath.

Step 6: Unscrew the PSU Wires

Use the Philips screwdriver to remove the wires from switch and IEC inlet to the PSU. They use ring connectors, so you need to take the screws out completely.

Step 7: Remove the IEC Connector

This step is far more straightforward on the T2 because you don't need the box wrench. On the U1 MINI or D2, use the wrench to remove the internal nuts on the IEC connector. Then remove the Torx bolts on the outside of the unit. Now comes the one wire-cut of this procedure--cut the red wire running from the switch to the IEC inlet. Bonus points for shaking, sweating, and cueing tense music as you do so. 

Step 8: Connect the Sbooster Wire Tail

You can use the silver screws that came with the Sbooster kit if you don’t want to futz with those nuts again. Make sure that the Sbooster logo on the connector (shown in the photo above) is facing upwards. 

Click the white connector back into the motherboard, making sure the black-marked wire is positioned towards the back of the unit (just align the latch the same way).

Step 9: Replace the Cover

This might need a little finessing to slide back completely. Fasten the eight Torx screws on the D2, and the three on the T2 to secure the cover.  

So what did we hear?

Lumin U1 MINI

Don't think for a second think that a digital-only product is immune to power-supply upgrades. Read more about this here. Check back for our report once we try this on one of our units. Customer feedback has been great--one of our regular customers upgraded his U1 MINI, and reports an increase in bass extension and a very noticeable drop in the noise floor. 

Lumin D2

We performed this upgrade on our trusty Lumin D2 that has driven so many listening sessions in our smaller demo room. Many of our PrimaLuna integrated amp customers have this rich Wolfson-chip DAC as their ‘happily ever after’ digital front end (until now, haha). We set up a stock D2 on one amp input, and an Sboostered D2 on another, gave them a night to settle in, and did some listening. 

Now, we’re not going to pretend this one is night and day, but the improvements are important. It is testament to the quality of Lumin’s internal SMPS that it’s this close. Other DAC brands show a much bigger jump in quality, showing how they much less optimized they are in stock form than the Lumin. In general, some areas of improvement are more important than others. An improvement to ease and flow may not be as dramatic as a huge increase in bass extension, but in the long term, the former is so much more important to your enjoyment of the music. Our test listeners could reliably pick out which input was the Sbooster-enhanced Lumin--especially after another day of run time. It had more air and ease to it, the music seemed more emotional and engaging. Switching back to stock made the sound tighten and harden up, especially in the upper mids. Bass with the Sbooster was more textured and had more bounce, and overall the instruments had more weight, without any bleed between them.

One customer wrote in an Instagram comment about the improvement he experienced: "The Stage! The stage became deeper again! The stage was much wider. the voices are a bit higher, so they are where they belong."

He also reported improvements to bass, and a more silky, less sibilant presentation in the highs. 

Lumin T2

One of the first things we noticed when testing a unit we'd modified for a customer, was the increased bass after the Sbooster. It's clear that the more dynamic and higher bandwidth T2 benefits from the low-impedance Sbooster supply. Customers have reported a startling improvement in all areas. We'll write more about this as we try it on either store demos or personally owned units.