[midfi]

only 2 caps replaced in my unit, and those are Obligatto's.  New Burr-Brown opamps as well.

got some longer RCA's so I could move TT away from the JD9 and swapped back the stock opamps, no change.


gonna do some tube rolling (and I got plenty!!) and see if that does anything...

[midfi]

figure I'd ask this question (no dumb questions right!?!) being there is no woofer cone movement does this rule out subsonic harmonics?  I've always been told by the elders if you have a good cart on a decent table that SS filters aren't necessary.

[Æ]

figure I'd ask this question (no dumb questions right!?!) being there is no woofer cone movement does this rule out subsonic harmonics?  I've always been told by the elders if you have a good cart on a decent table that SS filters aren't necessary.

Just plain ole infrasonics, not "sub"sonics. Fundamentals always come before harmonics. If you were to pick up your tone arm and accidentally "drop" it on the record, you'd definitely see your woofer cone jump. But it kind of depends on the enclosure. A sealed enclosure controls the woofer below the woofer resonance. A woofer in a reflex or open baffle enclosure is unloaded below the woofer's resonance. If the amplifier volume is turned up loud, the woofer can literally jump right out of the box!

[midfi]

okey dokey then!  update. took obbligato's from position that everyone else have them soldered to and installed them to the same spots that the factory caps came from, still humming...   I'm going to bed I am bummed the %$#@ out...   pee's me off too because it sounds so danged good.

[Ericus Rex]

figure I'd ask this question (no dumb questions right!?!) being there is no woofer cone movement does this rule out subsonic harmonics?  I've always been told by the elders if you have a good cart on a decent table that SS filters aren't necessary.

It's not a matter of good vs bad cartridge or arm.  It's the compatibility of arm and cartridge.  If you see no strange woofer movement you should be ok as is.

[midfi]

no woofer movement at all so I'll check that off. I switched my 721 with the 1219 in the bedroom and the hum didn't follow it so I can rule that out as well. Both units have the same brand RCA's (Dayton Audio) on them so I'm kinda at a loss...  Switched between 3 different carts too. 

[midfi]

I would unplug your turntable/tonearm/cartridge from the Jolida and insert shorting plugs (RCA) into the Phono input jacks and listen. You Jolida should be dead quiet, if not then your Jolida has a problem.

hacked up some junk RCA's and yes it still hums while shorted...  Gonna chap my hide to put a 3 week old piece in the shop 

[SteveFord]

I don't know if this has anything to do with your situation but mine just had a heallcious hum and then one channel was weak.
After much cursing and screwing around it turned out to be one of the leads to the cartridge. 
Did you swap tubes yet?

[Æ]

I was just reading about a certain Grado cartridge. Apparently some phono cartridges aren't happy in the presence of unshielded turntable motors. Many a motor "radiates" an electrical field and the cartridge can pick it up.

I also remember reading a magazine article with Corey Greenberg modding a Rega turntable. He installed some shielding material over the motor, motor compartment, to deal with this sort of problem.

(for Rega 2/3, from an article in Audio 1998 by Cory Greenberg)

The material used comes from Magnetic Shield Corporation and is called Mu-Metal. There is a lab kit that contains several sheets for $80, CO-NETIC AA for low intensity fields and NETIC for high intensity fields.

Shielding the motor with the NETIC didn't work so he tried placing the CO-NETIC sheets on the base under the platter, and this did it.


One can buy directly from the company 630/766-7800; ask for product LK-110. 

[midfi]

Fixed!

All I can come up with was maybe one of the power cords or something was loose.  I tore the entire system down (it needed dusting bad anyways...) and cleaned and checked everything.  Hooked up the basics with it spread across the living room (wife not happy  , oh well) and no buzz.  Hmmm....
System is back together and quiet as a church mouse, hope it stays that way. Thanks to all of you'ze guys for your input 

[AllynW]

 ! would like thank Midfi and all the responders to this thread.  I had the same issue with my JD9, searched yahoo which got me here.  Before the search I had checked connects, except power cord. I even changed the cartridge.  This thread helped and the hair on the sides of my head will grow back soon. Thanks again and have a Happy Thanksgiving!