So, this is my first cob build, but not my first DIY light. I built to a modest budget, and chose Citizen over Vero 29s after crunching the numbers and realizing Citizen is way ahead of Bridgelux at the moment, likely because they are a generation ahead right now.
These are a minimalist design, meant to be easy to build in modular chunks, with aluminum angle, pre-drilled heatsinks, and hand tools.
The parts for one lamp, not including screws and wire:
4x Citizen CLU048-1818 $100
1x Meanwell HLG-120H-C700B $52
4x Mechatronix 9980 Xtra heatsinks $38
4ft 3/4 x 1/8 aluminum angle $10
Total with CLU048-1818: $200
Draws 160W at the wall, ~167lm/W @ 3500k
Same build with CLU048-1212 would be $150, and ~160lm/W. 1212 is a great deal, if it was easily available. It isn't. This type of build would work fine with anything smaller than a 3590, like a CXB3070 or Vero 29.
I wanted one cob per square foot, so with the heatsinks that ended up being two 16" and two 12" lengths of aluminum angle, in an H shape like so:
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Honestly, single rivets and a dab of epoxy would have been just as effective as two screws in preventing slippage. I just wanted to be able to dismantle if I forgot anything, but it all went together fine.
Then the heatsinks, which I attached with two thread rolling M4 bolts each. The holes are already drilled in the heatsink for a different cob holder. Test fitting the driver as well. The HLG-120H is a perfect fit for the 12" spacing.
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And the hard part was over at that point. I only snapped one bolt head, which is pretty good for me.
Skipping to the finished light, I used solid core wire. If this was something that would be flexed a lot or taken apart and put back together a lot, no way. But I wanted something that stayed neat without being fussy, so it was perfect here.
Editing to add, I forgot to mention the wire routing holes were sanded smooth to prevent wear on the insulation. Alesh shows safer and potentially neater routing aids here
https://www.rollitup.org/t/cheap-and-cheerful-diy-using-citizen-cobs.909460/#post-12606160
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Love these cob holders. I ordered the Ideal to try as well, but they were fiddly as hell, and these allow an Angelina to attach directly.
The only other interesting bit is the switch. A bit of magic with some resistors and a DPDT on-on-on, and et voila:
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Basically just putting one or two 24k resistors in series, using crap I had around the house. The 100% setting is an open connection between the dim wires, so it runs about 10W over the 150W it pulls with a 100k resistor.
And that is about that. Some more pictures:
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