I use 47 Labs OTA Sakura with my Supratek Syrah. I find them very good, but I haven't compared them to much. Some users changed from Valhalla to the OTA, so I kind of use these based on faith that they're very good. Check out the long thread on the OTA. I'd be keen to hear what others are using though.
For the hum and hiss, I recommend keeping the Chardonnay as far away from the power amps, and the Chardonnay power supply. I noticed some hum too, but once I rearranged stuff, the hum disappeared. I also got hum from using certain tubes. Again, careful choice of tubes (particularly the 6sn7 ones in the Supratek) can reduce or eliminate any hum. I'm using Sylvania metal base, which are awesome but incredibly expensive. I guess you get what you pay for sometimes though.
For the hum and hiss, I recommend keeping the Chardonnay as far away from the power amps, and the Chardonnay power supply. I noticed some hum too, but once I rearranged stuff, the hum disappeared. I also got hum from using certain tubes. Again, careful choice of tubes (particularly the 6sn7 ones in the Supratek) can reduce or eliminate any hum. I'm using Sylvania metal base, which are awesome but incredibly expensive. I guess you get what you pay for sometimes though.