Quote:Hey guys, thanks again for the info. I got the DWX speakers in today. I really like the sound, though they are a little bigger than I was expecting! However, I am having a somewhat unanticipated problem. I have a low hum that is audible when the speakers are not playing music. The hum starts maybe 5 seconds or so after turning on the Zen Torii Jr. v2. I tried swapping out the input tubes and even the rectifier tube, but it makes no difference. The hum remains constant no matter what I do to the volume of the Torii. I'm guessing this is a ground loop issue that is perhaps exacerbated by having very efficient speakers?
I would very much appreciate any tips on how to deal with this. It is essentially inaudible while playing a record so not the end of the world, but I'd like to solve it if I can.
First thing I would like to throw out here is that our simple rule is that if you don't hear hum from the listening chair, 'it doesn't hum'.
Setting the hum level in an amplifier during it's design phase is a balancing act against dynamics. More hum, more dynamics, less hum, less dynamics. This is why there is a low level background hum present with sensitive speakers. It is by design and ensures the sound is good. Without it, the soft would be softer and less dynamic, less fast, more like everyone else's hifi crap. Whoops, I thought that out loud didn't I?
Second, if a rectifier fuse blows the hum can be heard across the house. What hasn't been mentioned here is that in a push pull amplifier like the TORII and ZMA, the output tubes have to be matched pairs. The tighter the match the less hum there will be.
Steve : )