Jolida JD-100 New unit with bad HUM.....hum

Mine is dead quiet. Except for a slight tube hiss when I have the volume very exaggerated. e.g. to hear the tube hiss!

If you power down the CDP (with the switch on the front panel) do you still get a hum? Try unplugging the power from the back of the CDP, do you still get a hum?

Hum is usually associated with ground or AC issues. It could be an an internal issue with the CDP.

Hiss, just like tape only much much lower in volume, is typical with tubes. Usually hiss is not an issue, very faint to inaudible at normal listening levels.

Macrophonics, or tube ringing, can be an issue. It can also be a hum (usually not though). Macrophonics occurs when your tubes are being vibrated, either by an outside force or even by your speakers themselves. Isolation feet, boards, slabs, devices, cones, and spikes can all help. I use Vibrapods under my CDP. Place the CDP on a nice sturdy shelf all to themselves. This is better than stacking. Nearby speakers, magnets, or power supplies may have a negative effect on tubes too (although I am not sure of this, other A'goners probably will).

Thanks guys for the response,
I do think this is a defective unit after a long listening session last night. I tried classical (piano solo’s) and some chamber stuff and unfortunately it was a lesson in frustration. Completely unlistenable. Spinning some rock and r & b stuff was much better as it veiled the hum and gave me a glimpse of the sonic qualities of this unit. My first instinct was an AC problem. The hum is audible at just over ½” power (200watt per side adcom amp) at my listening chair almost 10’ away even with the Jolida powered off. Turning the amp up from ½” power and it gets exponentially worst. Hum disappears as soon as I unplug the cdp's power at IEC. I’m reasonable confident that is not an isolation problem as the Jolida sits on the top TT shelf of an Atlantis Reference 5 rack with a basement slab floor under it. Speakers are 130lb NHT 3.3 again with spikes on slab. Regarding the hiss ??? maybe there……under the hum somewhere???? I guess when it rains..........the reverse on this unit is very jumpy also. Looks like I will be talking with Wally from Underwood hifi first thing in the am. Thanks so much for the help. T. J.

P.S. Last nights listen to John Hiatt’s mofi Bring the Family with Ry Cooder’s slide work on Lipstick Sunset made me forget about all bad vibrations in the world………for a little while.

If its humming when its plugged in but not powered up. It is reasonable to conclude that its an AC issue (ground loop). That doesnt rule out defective internals of course.

Do you have cable (video) running into or through this system? If so, unplug it and see what happens.

You say you tried grounding the unit. Without checking any manuals (meaning I could be wrong) did you tie your components together via the chassis'? Off the top of my head, I think thats how it should be done. I'll look it up later or maybe a fellow A'goner who knows can help us with this one. Right now I am making a pot of chili so I can't dig out the manuals just yet.

Dont worry about tube hiss. Unless you have a bad tube, it is so low that you have to turn the volume up well past any reasonable level just to hear it. If you had a CD playing while it was turned up you would probably be well into audible distortion or even speaker damage volume levels.

Thanks again Distortion
I do have video running as I'm using a HTR as my pre amp. I'll go try the disconnect and see what happens. I’ll let ya know. I do believe that daisy chaining the grounds on each case is correct method as it would give all the same ground reference but still the nasty hum!!
Great day for Chile here in Colorado with a mild snowstorm here in the foothills and major up on the passes (2’ or more). I made a batch 3 Sundays ago that had to amount to about 12 to 15 lbs. I think I’ll pull some out of the freezer!!! Do you think a Chile recipe thread would get us booted????

Just a thought I forgot until now, when I bought my JD100 it replaced a 15 year old Philips CD carousel. The Philips only had a 2-pronged plug, the JD100 of course has a 3 prongged plug (ground). When I first hooked up the JD100, I had a tremendous humm. I e-mailed my dealer and he told me I may have a ground loop. I put a cheeter plug on the Jolida cord at the outlet and problem solved. I have since installed dedicated lines and no humm at all even with the grounded plug. I guesss I'm asking if the cdp that you replaced had a 2-pronged plug? You may be experiencing the same thing? Let me know.