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

I am in the process of breaking in a Jolida JD-100 C. Johnson’s mod #1. I received the cdp last night and have played on repeat for 15 or so hours. Out of the box listening was a little rough but improving every few hours. I like rock and roll and a bit Loud (so I’m told). I’m very concerned of a distinct hum that I am hearing at moderately high listening levels especially when I pause the cd. I have checked the power on both a house supplies and through a 5kva isolation transformer the I installed for my components. Tried grounding the JD-100 case from the ground terminal provided on the unit but no help. I have changed interconnects still the hum is there. I have change inputs to my pre and still get the hum. The CJ mod has upgraded output (RCA’s) so I tried the original and still the hum. This is the first experience with tubes I have had since the 70’s and I don’t know if it is just the normal tube hum or if I have a defective unit. Anyone’s advice would be greatly appreciated. Thanks T. J.
Can't help you beyond the fact that mine is mummless at any volume. Dosen't sound normal for this unit.
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.
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.
Call Chris at Parts Connexion and describe your problem. He is enormously helpful and friendly. I had to send back the first JD-100 I had modded from him because there was a problem with the volume in one channel. He had me Express mail it to him (at his expense) and replaced it with another express mailed to me the next day.
Holy cow! My degree is in Mechanical engineering so naturally, if I can't see it I can't understand it! My head is still spinning after reading your detailed response. I'll just let it go and assume that my little 3-pronged vs. 2 pronged response was as helpful to you as my wife asking me if a sharper pencil would help me with a particular difficult kitchen remodel last year! I'm sure the rest of us are curious to know what your dealer has to say tomorrow. It really is too bad because the Jolida is one fine player in it's price range. Good luck.
The Chili came out great. Needless to say I ate to much. I doubt they will boot us for Chili recipes, although if it gives the powers that be indigestion.....Hehe.

If you're like me, I have neat and tidy little boxes with all my leftover goodies. See if you have a powercord without a ground (the original Yamaha PC) and give it a try. Essentially lifting the ground. Of course if you have chased a ground loop off from your turntable you will be well able to track this one down. The AC setup BTW, is much better than mine, I can understand your frustration after such painstaking preparation.

I assume both channels are humming, which rules out a tube failure. Unless they both failed (what are the odds) or a catastrophic failure effects both outputs (I dont know, maybe). You could try out different tubes. I presume with the Mod package that you got upgraded tubes, so you probably have the stock tubes.

After RF hum from the cable, ground loops, and fragged tubes, I begin to run out of ideas. I am sorry you're having this trouble. I agree with Mijknarf, once you get the ghost out of this machine, I think you will be very pleased.

As far as the Chili, its pretty much standard fare chunky style. I dice a couple of Jalepenos and saute them in olive oil in the bottom of the pot. Open a window if you try this. The fumes are distressful to say the least. 'bout an update?? What did you find out?