LOL Funny thing the internet.
I had
THE EXACT same PSU (Hyper Type R 530 watt) and I found the noise from the second fan also disturbing, especially during heavy sessions of gaming.
Therefore, I decided to disconnect (disconnect meaning cut the wire as too lazy to open the PSU) the smaller, after a few months, the PSU blew up, although the process was gradual, whereby, I started to smell (you know that particular smell PSU produce when they burn) something from a couple of weeks before the PSU went. I did not know what the smell was and so ignored it, as Inever had a PSU go before this.
Basically, the answer is sure, you can disconnect the fan, BUT make sure you are insured


btw, that Hyper was quite expensive when I bought it, and after that I have had two cheap (£10-£15) pSUs and both were fine (one was noisy so swapped it), however, both worked perfectly with 4 hard drives, X1900XTX, AMD X2 4600 + loads of extra cards.
Actually, thinking about it, that Hyper took out my X1900XTX, which I found out about from someone on these forums who bought it off me. My computer would shut during heavy gaming, and I hought that it was the new cheap PSU, but when I sold it, the person still had the same issue, so I refunded them their money and it now sits somewhere.
HYPER=DO NOT TOUCH