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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
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Is it safe to assume that you have everything grounded properly? One ground lead from the turntable bearing hub and one from the tonearm follow the signal path. So both ground leads should be tied to the SUT, which in turn should be tied to the Io. Are turntable/SUT and Io all plugged into the same circuit? If not, they should be.
suteetat OP
435 posts
 
I only have ground from tone arm to Sut. I played around a bit with ground wire from motor unit and plinth to isolated transformer ground that did not do anything. I use tw black Knight Battery power/speed controller on my Raven AC 1 turntable. I tried both with ground lead connected and disconnected between Sut and Io. Tw and Io is plugged into the same conditioner that went to the same isolated transformer. I am not sure it this is a ground loop problem as groundloopmproblem that I saw in the past tend to be there all the time even when music is not playing. In this case, I only get the hum if the needle is playing.
tbromgard
814 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
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