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

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.

Thanks Mijknarf,
My old cdp is indeed a 2-pronged plug (Yamaha carousel). Although I am not positive that the hum is not a problem of the supply power on my end and not an internal problem with the unit I don’t think it’s on my end. I have tried both standard utility power (110v) and a power system that incorporatea a 5 kva copper wound isolation transformer 230v primary and 110v secondary witch feeds a 125amp sub panel. The center tap of the transformer derives the neutral and ground and does not have a physical tie to the utility company, rather a grounding electrode system made of (4) 3/8” 8’ driven ground rods and develops the ground reference from that (no grounding or grounded tie no utility “noise”) 4 separate dedicated 20amp circuits serve my components each with #10 grounding conductor using #10 stranded wire from sub panel, terminated with sta-con spades connectors to Leviton hospital grade 20amp receptacles. The transformer is active and pulls almost 8 amps at idle so I installed a contactor ahead of the transformer with a 120-volt coil wired to a single pole switch to turn the system off when not in use. Although this system is not NEC compliant (don’t try this at home) is has worked wonders in terms of power quality and got rid of a nasty ground loop I had on my turntable for years. Nonetheless the Jolida when powered by the utility company or the transformer hums like…. er……. well it hums. Any problems with the reverse on your unit??? I did try removing the video connections to my HTR with no success. Thanks again!! T. J.