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.
tjtrout20
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.