This paper investigates the effects of non-ideal Digital-to-Analog Converters (DACs) on the modulated signal in Filter Bank Multi-Carrier (FBMC) transmitters. The mathematical model of the DAC for FBMC signals is described and evaluated. First, a closed-form expression for the optimal clipping threshold is given, considering uniform quantization in the DACs as a function of the bit resolution. Then, a further optimization for the placement of the quantization levels is proposed, considering non-uniform quantization to maximize the Signal-to-Distortion and Quantization Ratio (SDQR) at the output of the DACs. Finally, an upper limit for the SDQR is also presented using a Lloyd-Max quantizer.