Simple parallel SMD LED circuit(need help)
No, it won't work, or at least not very well.

But not because you have red and blue LEDs.

It won't work because even LEDs with the same color will have slightly different forward voltages, especially if they are at (even slightly) different temperatures.

So your three blue LEDs in parallel won't light up equally, and your three red LEDs in parallel won't light up equally. Possibly the difference in characteristics will even be enough to damage the LEDs.

The better solution is just to use a separate resistor for each LED.







simulate this circuit &ndash; Schematic created using CircuitLab

Or, if you have a higher-value voltage source available, place all the LEDs of the same color in series so that they are sure to all get the same current.