Just a reminder for PC users: make sure you've spent time optimizing your PC. Go through your bios, check your control panel/Power options, format your drives properly (FAT sounds best), etc. If you have ASIO or similar drivers like XMOS etc., play with all the settings, doublecheck your Audio adapter settings (sometimes your PC will reset sample rates, you never know). Test different USB outputs. All of this is free.
I myself forgot to turn off C-States in Bios and some other settings and now I get another bump in sound quality. Cost me nothing.
Make sure to use Deoxit to clean contacts before using. All contacts actually in your chain. Another little bump in sq for very little money. Tested last night with SATA for instance, dac jack and usb inputs and it definitely helped. Easy to forget little things like that.