I just built a trial COB set-up...it's too ugly to show, but it was my intent to learn about this type of lighting by getting my hands dirty and mostly winging it.
I know nothing about BIN's and other LED specific lingo....All those acronyms hurt my head. I read most of this stuff and my eyes glaze over.
I'm a computer tech and have tons of computer crap laying around including piles of power supplies and CPU heat sinks. I went with CXA 3050 mostly due to the price....It seemed to produce the right wavelengths and if I was going to screw up a COB....it might as well be a cheap one.
I'm lighting four of these using a 500w PC power supply and DC power boosters...one for each cob....I have them running at 35 volts and all I know is that they're bright as shit.
Everything seems to be working as anticipated and now have two plants starting their 12/12 under this set-up. They haven't died.....so I guess that's a good sign.
I've re-ordered eight more of the CXA's based on my 6 days of experience with the trial set-up. I've gutted a 6 bulb T5 fixture and plan on using it for the new light. I'll be using the 4.2ish (it's just over 4") heatsinks and 70mm low profile CPU fans. I'll be using the PC power supplies....maybe one for each two cobs....why....I don't know. They will be driving the boosters as I am in the first light.
I'm telling you all this to ask your opinion of what I've done right and what I've done wrong....so far. Don't spare my feelings, I wouldn't ask if I was sure I know what the hell I'm doing. Please spare me as many acronyms and math as much as possible.
P.S. My focus has not been about efficiency as it seems both you and Supra are driven to get the best efficiency possible...considering I've been running four 600w HPS the past few years, anything would be more efficient than that. What I'm looking to do is effectively replace my 600's with COB LED's....any savings is secondary....I just want the same yield and quality from LED's.