Hey Guys! Grand Master Level did an HPS vs LED comparison once before but it wasn't really a fair run as it was just a single LED fixture in a room off of his main HPS flowering room so he wasn't able to control the environment independently. He has switched one whole room over to HLG LED boards, I don't think these are quantum boards and I don't believe they are LM561C - they are a newer HLG model and i'm not sure if the diode is yet announced or if the fixture is released. He has 15750w of HPS vs 8755w of LED.
They are currently vegging under MH and will be flowered under HPS. should be an interesting comparison. here are the first couple episodes.
He is having his friday night live show starting in about 10 minutes. I haven't watched his show for a few weeks so this question may have already been answered previously, but I will be asking for more details about the fixtures and what diode is used.
Edit: The new fixture is called HLG Elite - it's water proof and a DE 1000w HID replacement. They have sent it off for third party testing to get the data like efficacy numbers etc
GML is using the HLG 550 which is the LM561C diodes - his previous test with the single fixture was with the HLG elite. apparently the new diodes won't have much difference in terms of efficacy but are water resistant and have a different form factor and maybe beam angle.