CMoy hum, but strange...

[3Double]

The last 15% of the work on the CMoy has taken upo 75% of my time, but that's how it goes the first time around, I guess...gettin there slowly, but surely.

I've just connected my input and am testing it out.

Everything seems fine except when the amp is on, but the source (sony MZ-R50) isn't playing. When I touch the MZ-R50, I hear a humming/buzzing sound through the cans. HOWEVER, when the source is playing, even at extremely low volumes, I can touch the case of the R50 and not get any buzz at all. The source has to be off, or on but not playing, or even paused for the buzzing/humming to occur.

Frankly, I haven't been using the DMM that often (only during the one instance that Tangent specifies what we should be looking for), because I don't know what to look for. I hook up the cheap cans and fiddle until the sound comes out right.

Thanks in advance (again!)

 

[Kenny12]

it has to do with groudning, is the ground on your pot connected to the case?

 

[bpribadi]

It's the AC hum. You need coaxial, or any shielded cable for the input, the interconnect between your source and your headamp. I had the same thing, and when I use coax cable, with the shield/screen grounded, the hum completely gone.

 

[3Double]

I am quite curious about how grounding works. On Tangent's diagram ( http://tangentsoft.net/audio/cmoy-tu...nn-board-1.jpg ) the jumper at the very bottom (it's at the very bottom of the light green loop in case you can't see it) is designated as the ground. So for every item that needs to be connected to the ground (volume, input, output) I've been running a wire from one of the two ground jumper tips to the required area. Is this the correct procedure?

 

[Pars]

Yes, that is correct. The entire light green rows (the two center rows of the board, running vertically) are the ground, so you may ground to anywhere there.

 

[Yiggy]

That cleared something up for me too. Thanks.