Help! I'm having a problem with hum/buzz from my Reference 5.2
I don't hear it when using balance XLR connections, only RCA. It's audible (just) when connected to my Violectric v200 with the volume cranked right up, but much more noticeable with my tube amp. At beyond normal listening levels it's actually pretty loud.
I've checked my other two DACs and both are completely silent, so it only happens with the 5.2. My impression is that it gets gradually worse the longer the unit is running. I assumed at first that I had a faulty tube but after checking I've concluded that it's definitely the DAC and I can even hear the hum through headphones when the amp is powered down. The hum is much more noticeable when the DAC is set to the high output setting - it becomes quite an angry buzz at full volume (with no music playing). It is loud enough that I can just hear it during quiet passages of music, although the sound is otherwise good. It's sufficiently annoying that I don't really want to use it with my tube amp.
Any thoughts? Has anyone else experienced this problem? The DAC is connected to my Mac Power Book via USB.