The newest QB-75 uses 144xLM301B
We've upgraded to the 92% efficient XLG-100-24-A driver, hence the small upgrade in price.
The diodes can achieve 3.03 μmol/J (approx. 224lm/W) efficiency at 65mA.
At 75W, the diodes are running at 0.172A, for 187.3lm/W pre-driver, 172.3lm/W post-driver, for >2.4uMol/J efficiency.
eg. Compare to HLG-65v2 2.35uMol/J (R3000)