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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
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
andyprice44
133 posts
 
I was dealing with a similar situation not long ago. I'm not sure if your phono pre-amp is similar to mine but, My phono stage has selectable dip switches that allow you to change your grounding. I had to to change my grounding where only the right channel is grounded. This eliminated all but a bit of the hum. Now it is only heard when I have the volume turned up really high. I cannot detect a hum/buzz at my listening position at normal or even higher volume. I have to turn my pre-amp up to max volume to hear a hum at my listening position. I can live with this. At this point I think it is noise from the tubes and not the ground. If your pre-amp has selectable grounding take a look at it.
suteetat OP
435 posts
 
Thanks for all the advise. I live in an apartment building so creating separate ground for my audio outlet is not possible although several of my friends who live in a house has separate ground rods placed specifically for their audio system. There is no ground switch on my preamp/phono unfortunately but there is a ground/float switch on my T100 SUT. Sometimes floating ground on SUT seems to help but sometimes not.
I talked to TW acustic and there is no provision to connect ground wire to bearing hub and they think that my problem is unlikely to be solved by doing that anyhow!
andyprice44
133 posts
 
I spoke to peter lederman from soundsmith this afternoon. I learned a new trick from him. New to me atleast. He said to only earth ground one piece of your audio equipment. If your equipment has a 3-prong power cord, get a 3-prong to 2-prong adapter. He said this helps to get rid of more ground hum. This makes sense to me as there is less chance of creating a ground loop. I have not had a chance to try this method yet but, I plan to. I am going to earth ground my phono stage and then connect the rest of my components to the grounding lug on my phono, bypassing the grounds on the powercords. I will post results on this method after I give it a try
suteetat OP
435 posts
 
Hmmm... as soon as I posted the message, the hum went away. May be I should complain more often :)

Some equipments do like grounding, even more so than just with 3 prongs AC cord. My Lamm pre/power/phono has extra ground posts on the chassis and I found that background noise is reduced quite a bit more by connecting those ground post to my isolation transformer as well.
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