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Need helps with hums, radio station in phono

My room seems to have all kinds of problem with some phono units. In the past, I had quite a bit of problem with getting radio station noise in some phono units but not others. The biggest problem seems to be in my Io Eclipse. I used to be able to fix it by connecting ground lead from tonearm to ground on SUT first (signal went straight to Io). Then last month or so radio station noise came back again and there is nothing much that help short of removing tubes from 3rd stage and reduced gain to 50 dB then use a SUT in the pathway. Sonically, I had not complain with using Dynavector 1:13 SUT although overall the gain is a tad on the high side. With Reed tonearm, I am still quite happy with the result.

Recently I installed Graham arm on my turntable and it gave a new hum problem. As soon as cartridge touch LP, I get quite a bit of a hum but no hum when the needle is lifted. I did not have this problem with Reed. I tried moving Io around as much as my shelf/cable/AC cords allowed. Playing with ferrite thing around cable, lift ground from AC, float ground on SUT, trying placing ERS paper around SUT, cables, Io, connecting ground cable from chassis to chassis of isolated transformer, nothing works. Everything I have is plugged into a power conditioner and Isoclean Isolated transformer. Sometimes the hum went away for a few days then it came back again. My Lamm phono has no such problem. I still really like Io Eclipse sound very much and definitely wants to keep it but I am at my wit's end.
I was told that Versa Dynamic used to make something that supposed to help with this problem but have not been able to locate any on Ebay or a'gon.
suteetat
tbromgard
787 posts
 
This is weird but will work-
Get a ferrite core and wrap it around your power core. All your radio interference wil be gone.

Here's an article:

Ferrite cores are small semi-magnetic iron pieces encased in a plastic snap enclosure. Designed to fit around power cords and interconnects, they block electromagnetic interference and unwanted high frequency information. Since ferrite shields can often affect these frequencies in the analog domain, it is usually used for digital and power cables where frequency manipulation is not audible. Ferrite cores have been used for years in the engineering, computing, and electronics industries
tbromgard
787 posts
 
Sorry-just saw you tried the ferrite core...did you try one on every power cord? wrap it twice? good luck.
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
You don't have a ground wire tied to your turntable? I have a Basis and VPI tables and both of them have a ground wire attached to the steel hub that seats the platter bearing under the turntable, as well as a ground for the tonearm.
suteetat OP
435 posts
 
Tbromgard, I tried it only with phono cable as I use Stealth Dream AC cord on my phono unit, not sure where I would find ferrite ring that big!.

Jmcgrogan2, hmmm... thanks about ground between phono adn bearing hub. I never tried that before and will talk with TW as I am not sure how to connect that. My VPI table does have that but I never had to use it before.
tanathen78
25 posts
 
Just food for thought, isolation transformers work on the idea of induced voltage. First core is powered from your home the second core has its voltage induced keeping everything you plug into it seperate from the "dirty" power supplied to your home. They are fantastic for sensitive equipment. However if this is a plug in unit (three prong) the ground is not isolated from your home and that can act like a big antenna( all grounds in a home ideally are all connected in a panel together) every switch and outlet has a ground. Also dc voltage cannot be transferred from the isolated coil back out to the street and it is not regulated into ac sine wave (also a reason for a iso transformer to prevent all but correct voltage getting to your equipment). So while it likely wouldn't matter even slightly in your case , trace dc voltage can get back onto these coils sometimes and cause harmonic issues, usually this would happen in office buildings with a decent amount of computers. The radio station pick up though could be due to the grounds in your home. To find out if it is the case try taking the outlet you are plugging into out of the wall and remove the ground wire, then put a new wire from that outlet directly to the dirt outside of the home. Of course shut the breaker off first. You could also just remove the ground and see if it goes away before you run the wire. It is not safe to leave it that way though. There is a correct method if this is the problem to fix this by code standards. What I mentioned would just be to test.

Regards,
Bill
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