If the LED fv is '3.6V' remember that's a 'typical' figure. You need to allow some voltage margin for production tolerance plus current-limiting circuitry (which may be no more than a resistor, depending on the power supply characteristics). So if you're putting ten LEDs in series, 36V won't be enough. IMHO you would need at least 38V. But as Colin says above, you can do without the extra supply by using LED strings of 3 + 3 + 3 (+1 if you really need 10 altogether). I'd use a respective constant current source for each string (not constant voltage, because the LED vf may change as the LED heats up) .