In this work we show the results of low frequency noise measurements (LFNMs) in staggered bottom gate top contact organic thin film transistors (OTFTs) made with dinaphtho-[2,3-b: $2^{\prime} $ , $3^{\prime} $ -f]thieno[3,2-b]thiophene (DNTT) as semiconductor layer and CYTOP $^{\text {TM}}$ as dielectric layer. The measured 1/f noise follows a correlated number-mobility fluctuation mechanism with an extracted trap density $ < {10}^{{10}}$ cm $^{{-{2}}}$ eV $^{-{1}}$ , the lower value ever reported for OTFTs and comparable to c-Si devices. On the other hand, the extracted Coulomb scattering parameter is in the order of $10^{{7}}$ Vs/C, in line with previous measurements on organic transistors. In particular we found similar results from device batches with technological differences and a much lower noise from reference devices with SiO2 dielectric, suggesting that the low noise and extracted trap density can be mainly attributed to the quality of the DNTT/Cytop $^{\text {TM}}$ interface.