• Here is a link to the full explanation: https://rollitup.org/t/welcome-back-did-you-try-turning-it-off-and-on-again.1104810/

COB color temps: (3000K + 4000K)/2 = 3500K?

miggaman

miggaman

Member
Greetz fam,

I cannot find the 3500K COBs that I want.. but I can find 3000K and 4000K of the COBs that I want. I wonder: is it then advisable to mix an equal number of 3000K and 4000K COBs to get an average of 3500K? Does it even work like that?

For the record, COB series in question is the Bridgelux Vero 29 Gen 7
 
H

HardG

Member
Some plants will have less red (4000k) than the others (3000k)... An example it could be mix 2700k with 5000k... the average it couldnt be 3850K ;)
 
S

Shugglet

Well-Known Member
HardG said:
Some plants will have less red (4000k) than the others (3000k)... An example it could be mix 2700k with 5000k... the average it couldnt be 3850K ;)
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This makes no sense. Reads like a mad lib.

Light does not mix like this last I checked.
 
The Dawg

The Dawg

Well-Known Member
Olive Drab Green

Olive Drab Green

Well-Known Member
Why are people saying the light "doesn't mix?" I'm under the impression LEDs which overlap with each other amplify their PPFD where the overlap occurs. That said, not sure how spectrums blend. I kind of believe they do, but I think the 3500k is probably better than using either/both a 4000k and/or a 3000k. You don't need to focus on reds or blues depending on the stage of life. Just get something closest to neutral, bright white that peaks naturally in blues and reds. Pretty sure that's your best option. Then again, "your best" is subjective, so take what I'm saying with a grain of salt.
 
Olive Drab Green

Olive Drab Green

Well-Known Member
miggaman said:
Greetz fam,

I cannot find the 3500K COBs that I want.. but I can find 3000K and 4000K of the COBs that I want. I wonder: is it then advisable to mix an equal number of 3000K and 4000K COBs to get an average of 3500K? Does it even work like that?

For the record, COB series in question is the Bridgelux Vero 29 Gen 7
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Why are you unable to acquire a 3500k 7th Gen Vero29C? Talk to @Rahz, or @CobKits; maybe they can send you the right direction. Rahz/Tasty makes fixtures with 3500k 90CRI 7th Gen Vero29Cs, so he probably knows where you can get some. Likely COBKits, as well.
 
miggaman

miggaman

Member
@Olive Drab Green It didn't occur to me to ask people here. I've been limited to what Digikey has to offer. They only have 3000K/4000K/5000K, in various array configurations. Will ask, thanks!!
 
miggaman

miggaman

Member
Olive Drab Green

Olive Drab Green

Well-Known Member
miggaman said:
Looks like really good stuff, @The Dawg . I want to do something similar, in a smaller space, maybe 3x3", or 4x4" foot. The challenge is now staying under 200W per driver but getting drivers that allow 4 COBs per bar and therefore, lower voltage COBs. These newer Gen 7's have not yet flooded the market :(
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In a 4x2 closet, I use 3 COBs/270w total to round out my closet of all shade, but I probably could have grown with just two, or about 178w (156w being used by the emitters.) I use higher-amperage lights than most I've seen until more recently. Like, I believe in his vids, Growmau5 uses between 700-1400mA. I use two separate dimmable 2150mA drivers for my two Crees and one 1670mA driver for my Vero29C.
 
F

Fevs

Well-Known Member
I know it ain't led, but I prefer the growth under 4200k 315w cmh daylight lamp, over the 315w 3100k elite agro lamp. I have used them both together too and the plants just loved it! (: If i had to choose 1, it would be the daylight lamp, which I got over 1 gram per watt with in flowering + the buds looked greasy with resin.

If you have the option, mix and match. Go for 50% daylight 4000k cobs and 50% flowering 3000k cobs on each bar! I think the sun is about 5500k, but the 4000k sure takes care of veg nicely. No need for anything higher than 4000k.

I did an excellent grow with a 4500k crisp white metal halide, but reckon it was right on the borderline... Extremely good plant health, but yielded 1/3 less than a hps grow running alongside it. But quality was better under the mh.

Either way, good luck and enjoy the ride ;-)
 
miggaman

miggaman

Member
@Fevs I think I will do that: mix and match.. alternating COBs with 4 COBs per bar can make a checkerboard pattern to have mostly (?) even spectrum distribution. I'm doing a small build first (a "dry run" with 3500K Crees) and when it comes time for the larger build, I will do the checkerboard. It's a shame that Bridgelux hasn't made their new product line readily available :(
 
Olive Drab Green

Olive Drab Green

Well-Known Member
Fevs said:
I know it ain't led, but I prefer the growth under 4200k 315w cmh daylight lamp, over the 315w 3100k elite agro lamp. I have used them both together too and the plants just loved it! (: If i had to choose 1, it would be the daylight lamp, which I got over 1 gram per watt with in flowering + the buds looked greasy with resin.

If you have the option, mix and match. Go for 50% daylight 4000k cobs and 50% flowering 3000k cobs on each bar! I think the sun is about 5500k, but the 4000k sure takes care of veg nicely. No need for anything higher than 4000k.

I did an excellent grow with a 4500k crisp white metal halide, but reckon it was right on the borderline... Extremely good plant health, but yielded 1/3 less than a hps grow running alongside it. But quality was better under the mh.

Either way, good luck and enjoy the ride ;-)
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CMH/LEC is at least a new technology. HPS and MH are decades-old and inefficient. I can roll with anyone running CMH/LEC without any qualms at all.
 
Olive Drab Green

Olive Drab Green

Well-Known Member
miggaman said:
@Fevs I think I will do that: mix and match.. alternating COBs with 4 COBs per bar can make a checkerboard pattern to have mostly (?) even spectrum distribution. I'm doing a small build first (a "dry run" with 3500K Crees) and when it comes time for the larger build, I will do the checkerboard. It's a shame that Bridgelux hasn't made their new product line readily available :(
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How many plants for your grow.

And believe me, this hurts to say, but you should go with the new Seventh Gen Vero29Cs in 3500k/90CRI. I am a Cree fan and two of my fixtures use Cree CXB3590 CD/Top Bin 3500k/80CRI 36v emitters run at 2150mA each.

Between those two Crees, I have one more fixture utilizing a new Vero29C in the aforementioned specs running 1670mA. It puts out just about 100 more PPFD, and while lumens aren't really relevant, I get about 1,000+ more lumens. I hate to say it, but Cree is dropping the ball by not releasing a new generation of emitters. Bridgelux's Vero29C is proving to be better, although only slightly, but enough to make a noticeable difference. 100 more PPFD isn't a huge jump, but it isn't small, either.
 
The Dawg

The Dawg

Well-Known Member
miggaman said:
Looks like really good stuff, @The Dawg . I want to do something similar, in a smaller space, maybe 3x3", or 4x4" foot. The challenge is now staying under 200W per driver but getting drivers that allow 4 COBs per bar and therefore, lower voltage COBs. These newer Gen 7's have not yet flooded the market :(
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Here's Your Next Light Which Is The One I Would Build For A 3x3. (2) 44 Inch 420 Watt Bars Would Kick A 4x4 Azz. :hump:
 
F

Fevs

Well-Known Member
Olive Drab Green said:
CMH/LEC is at least a new technology. HPS and MH are decades-old and inefficient. I can roll with anyone running CMH/LEC without any qualms at all.
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Not debating whether cmh is better than cob or not, I posted the info purely about colour temperatures 'K'. Whether I used cob or cmh, I would still want a varied spectrum and a mix of 4000k with 3000k.
 
miggaman

miggaman

Member
Olive Drab Green said:
How many plants for your grow.
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I'm thinking 4 ladies in Scrog. Maybe 16 ladies and a little less Scrog. For sativas I'm thinking 1 lady in a 3x3 or 4x4 with some indicas/hybrids utilizing the rest of the space. Could get complicated---might lower some bars to be closer to the colas if I'm mixing breeds in the tent.

Olive Drab Green said:
How many plants for your grow.

And believe me, this hurts to say, but you should go with the new Seventh Gen Vero29Cs in 3500k/90CRI....
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Oh how nice it would be to get those COBs. This is what I'm looking at on Digikey:



So, this question goes out to everyone on RIU: which of you are down to pool some serious $$$ to someone you don't know so we can buy 50 COBs???
 
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