Sort of…
At a given current, say 4 amps, the 219c and SST-20 will be very close in output.
But, the SST-20 has a higher Vf, so would be slightly less efficient.
The big difference is that the lower Vf of the 219c will draw more current in a FET based light, like the IF25a and the TS21.
This higher current will give you a higher Max Turbo output… for a little while. The addition heat from the higher current will also cause the light to heat up and step down sooner.
In the example at 4A, the Vf of the SSWT-20 is about 3.4v. The 219c is about 3.2v and doesn’t reach 3.4 until >7A. The 219c won’t draw that much more current because of other limitations in the flashlight (battery, contacts, driver, wires, etc). Let’s say it draws 6A with a good high current battery. So the 219c will be brighter, but at the cost of 50% more current… gets too hot quicker!
My numbers are approximate, but I hope they help get to the point.
There was a discussion just recently about improving the “green” of the SST-20. I suggested “shaving” or “slicing” the dome of the SST-20 to reduce duv. Another suggestion was to use some Lee minus green filter. Both of these methods can help. But, it really depends on the bin of the LED you are starting with and what your preferences are.
My experience… not all 219c are good, and not all SST-20s are bad. There are good and bad bins of both.
FB