since you asked, why yes i CAN hijack this thread
i have a bunch of 2015 CLW 170W fixtures (72 3W osrams driven at just over 2W ea) that are great, almost new and have 10 more good years in them
why dick around with adding 660 monos (well over $2/watt to DIY something decent) when these are mostly 630 660, pretty efficient, and on-hand plug and play?
my current scheme is 6 of those blurples in a tents with 4 cob bars (bars could be extruded if unit dissipation is low enough, or also could be passive at lower numbers of higher watt cobs.
so somehting like rows of
COB BAR | 2 x CLW | COB BAR | 2 x CLW | COB BAR | 2 x CLW | COB BAR
vs say 6 of the cob bars sans blurples
so shooting for the following criteria with and without blurples:
5x9 tent = 45SF
nominal 20 par W/SF in bloom with driver/heatsink headroom to go up to 25 parW/SF
tunable cob spectrum for veg and bloom
so the standard bar would be either citi 1212s or 1825s
something like 5 1825s at 60W ea (3x 2700k 90 cri + 2 x either 4000 or 5700k 90CRI) on individual dimmers
cob eff = ~60%
6 of those bars would be 1800W = ~1050 par W with room to dim
4 of those bars would be 1200W ( 700 par W) + 1000W of blurple (~450 PAR W) in between
if i did the 5 cobs per bar @ 60W ea as described above it would be passive pinfins, alternatively to get better coverage i might do 15 citi 1212s at 20W ea (same 60%ish eff.), so like 10 2700k and 5 of the 4000/5700K.
that last option would be straight up el cheapo glue em to bars with epoxy and solder, save considerably on holder and heatsink cost