RSS Hands-on with LED Group Buy’s Lumia 5.2

Discussion in 'RSS Feeds' started by MASA Admin, 27 Feb 2014.

  1. MASA Admin

    MASA Admin Moderator

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    Last year, LED Group Buy introduced the Lumia 5.1 to the DIY LED community, and has had great success with it. But while some loved the simple setup of this high power, full spectrum LED, there were others that were left wanting more, and corrections to a few shortcomings. Well, say hello to the Lumia 5.2.

    The Lumia 5.1 was a massive step in the right direction for DIY LED builds, with an easy to use multi-channel multi-chip solution that handily addressed the “disco effect” that many people are angered by with more traditional LED setups. Keeping the individual chips tightly packed, much like the Kessil Dense Matrix LED, the issue of color shadowing is virtually eliminated. Major bonus points there.

    Where the 5.1 fell a little short was in it’s connection scheme. The use of a generic LED package (one that has been around for many years in high power single channel LED versions) forced them to solder wires directly to the tabs of the LED itself. These tabs sadly are not that strong mechanically, and many users ended up breaking off the tabs, leaving the LED virtually useless unless you were crafty.*Others also weren’t all that thrilled about the relatively unknown properties of the chips included in this multi-chip offering, and would have preferred LED offerings from the likes of Cree and Philips.

    LED Group Buy was fortunately listening to the feedback of their customers and the community, and came up with a slightly different alternative. Where the 5.1 was a purely custom LED solution, the Lumia 5.2 is more of a custom MCPCB more than anything else. That’s certainly not a drawback, as the LEDs on offer will certainly please a lot of users.

    The first obvious difference is that the LEDs on this board are actual discrete LEDs rather than chips populated in a single package. This allows for an almost infinite number of options from a color standpoint when using standard 3535 package LEDs. The majority of the LEDs used here are Cree, and as a result, will offer top notch performance. The remainder of the LEDs are the same units that LED Group Buy sells individually, and have been proven as reliable performers.

    • Channel 1 – 3 Hyper Violet (430nm) and 2 Cree XT-E Royal Blue (18v @ 700mA)
    • Channel 2 – Cree XT-E Royal Blue (16.5V @ 1500mA)
    • Channel 3 – 3 Cree XT-E Netural White and 2 Cree XT-E Warm White (16.5V @ 1500mA)
    • Channel 4 – 2 Turquoise*and 3 Cree XP-E2 Blue (17.2V @ 700mA)
    • Channel 5 – 3 Hyper Violet (430nm) and 2 Cree XT-E Royal Blue (18v @ 700mA)

    One thing that many may notice about the LED setup this time around is that there is no deep red channel. LED Group Buy decided that using warm white would be a better option for adding additional red spectrum to the light. While the impact may not be as great as dedicated red LEDs, the warm whites will blend better overall, while producing a similar effect. Some may notice from the pictures that all of the white LEDs look the same.

    The Lumia 5.2 that was sent to us happened to be a pre-production unit that only had neutral white LEDs populated on the white channel. While having warm white LEDs added to the mix would have been nice for testing, the use of only neutral white LEDs really didn’t seem to do all that bad. Color overall was nice, and of course, infinitely adjustable.

    The base that these LEDs are riding on is solid copper, just like the Lumia 5.1. It’s a seriously heavy chunk of metal that will do just fine at pulling all the heat from the 70W of LED power away from the LEDs and to the heatsink below. The profile is nicely machined, and looks very clean. The bolt pattern is set up to work with the MakersLED line of heatsinks, but it can be adapted to any heatsink with a little creativity.

    The correction to probably the biggest issue with the Lumia 5.1 lies in the surface mounted Molex connectors situated on each end of the MCPCB. The Lumia 5.2 ships with a few different choices of wire harness to allow you to connect a single unit to your drivers, or to connect multiple units together in series (you can connect two in series safely on most common drivers). Much like the unit itself, the harnesses pictured are pre-production, and may look a little different from what actually ships. The difference will only be in the wire color, as the Molex connector will be the same. The connectors fit snugly, and the whole assembly feels very solid compared to the Lumia 5.1.

    So, what do you use for optics? LED Group Buy thought of that too by adding mounting points for the same optics that they introduced for the Lumia 5.1. These adjustable lenses offer a wide range of angle options to suit almost any need, and fit easily with a little bit of silicone to keep them in place.

    The new Lumia 5.2 isn’t intended to be a replacement to the original 5.1, as they both have slightly different spectral profiles, and costs. The additional $25 in cost may sway some to the Lumia 5.1 if they are on a budget. Some may look at the difference in power and think that the 5.1 has higher output due to the 30W increase in power, but because of the higher efficiency LEDs on the 5.2, the total optical power should be pretty close.

    Overall, this is a fantastic LED offering, and certainly one that stands out in an already crowded segment. The use of premium LEDs and a solid connection scheme shows that LED Group Buy is serious about taking care of the communities wants and needs, and they have certainly delivered. The Lumia 5.2 is currently for sale, but quantities are limited at the moment as production ramps up.
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