Bah Hum Bug

I am having an issue with hum.Hum is only apparent in very quiet passages while listening to lps or when unit is in idle mode.Unit is Dead hum in cd mode of operation.

I am running a Fosgate Signature Phono amp,Thorens Td124 with Ortofon Silver Meister Cart,Wright AU-1000 linestage, 2A3 SET power amp into Klipsch Heresy speakers.

When ground is is attached from TT to Phono amp the hum is intolerable so I run the TT with no ground to Phono amp.

I have tried cheater plugs and that has made no difference.

When volume is turned up say past 1 oclock in either the Wright or the power amp the hum is very noticable. Is this indicative of the high efficiency of the Heresys and 2A3 tubes? or is there some other thing going on here?

Please help.Thanks.
When did the hum start? Which piece of gear did you install last when the hum started?

I would think that a solid state phono preamp would work best in a high efficiency speaker system.
Fosgate sig was the last addition. But I believe the hum was there before as well.
so annoying. the fact that your system is dead quiet with the CD input seems to eliminate the pre and the power as a source of the hum. so it's the TT or the phono - which are both way more sensitive than any other piece of gear. i had a TT pickup mobile phone data signals over the system if my iPhone was to close to it.

getting rid of hum is a process of elimination. so i'd double check the gain/load setting on the phono. and if you've got other equipment nearby that's not associated with music playback i'd turn all of that off to see if that resolves the problem then start plugging in one by one to double check. cable boxes are prime offenders.
I don't know your equipment, but hum can be a real downer.

You might try a different set of phono cables. Some cables have the shield connected to the ground plug at both ends, which can create a ground loop. Other cables have no shielding at all (a la Kimber Kable), and others ground the shield only at one end, usually marked with an arrow. That end should be plugged into the phono stage, not the table.
Try some different cables (cheap ones might be fine for testing this) or make your own.

The fact that you have hum on phono and not CD is probably due to the extra gain through the phono section. There might also be hum on the CD inlet, but at a level too low for you to hear.

If cheater plugs (lifting the ground) didn't help, I doubt you have a ground loop through the AC line. But it helps if all your gear is plugged into the same AC line. Even a small difference in potential (a few millivolts) can show up as a hum.

There are also some "humbuster" types of products which are basically tiny unity-gain transformers that you can insert in your cables to galvanically isolate two pieces of gear. The good ones are not cheap, but might be worth trying (borrowing if possible).

Hopefully one of these ideas will get it!
Is it the same with other cartridges too?
I have had similar problems and it was the cable that connected the arm to the phono preamp. However, I can easily get noise if I raise the gain too much. I mean more gain than it would need to be very loud. So, I agree with those who suggest cable problems. I use a very low output moving coil, and perhaps a "louder" cartridge would be worth a try. I use Kimber Silver Streak between my Denon 100th anniversary cartridge and Parasound JC-3. Pre amp is Audio Research LS 17. I need very little gain for high volume, and I am frankly surprised by how quiet it is. Good luck, you may need to find a helpful shop.
2nd to Jmc.
Fromunda, I had the exact same problem as you. It was phono stage related. I tried cheater plugs, not much difference. I ended up purchasing the Granite Audio 502 Ground Zero and that seems to have worked for me, with some experimentation of settings. Let's just say that I am no longer cognizant of the hum at higher volumes without a signal. Maybe it is still there, I don't know, but I've not fixated on it since the 502. I've moved on. All the above advice is good. Clean you interconnect contacts, too. they could be dirty with poor contact. Lastly, I had an expensive Kondo KSL silver interconnect short circuit internally. Kondo repaired, and it is as good as new now. That caused a very loud hum different from your's.Still, clean the contacts.
All equipment is plugged into Fuman Elite power conditioner
+2 on the phono cable. Drove me nuts with my Manley Steelhead. Changed tables and arms and cables until It is now silent. does the level of hum change at all if you move the phono cable around. that might help isolate if its due to proximaty to a hum source, or possibly a small break in the cable sheathing. You just have to work through a process of elimiation.
Yes you know the sound does change when I move the phono cables. These are brand new Shielded Tributaries A6's. The hum would change upon moving them around with the old cables as well so I replaced them thinking that was the culprit.
02-26-13: Fromunda
Fosgate sig was the last addition. But I believe the hum was there before as well.

Was your previous phono preamp a tube unit too? Hum is not uncommon using tubes in high efficiency systems. Try a SS phono stage and see if the hum goes away. It doesn't have to be an expensive one, you can find a SS phono preamp for under $100, it should at least let you know whether or not the Fosgate is the problem.

I have something like this as a back up to test for issues like this. In my experiences, I prefer solid state for very low level signals like vinyl. Tube line stages and amps are great, but you have to be careful with tube phono stages. The more efficient your speakers are, the more likely you are to hear tube artifacts in low level amplification.
Yes previous phono stage was Pro Ject Tube box MK11.
02-28-13: Fromunda
Yes previous phono stage was Pro Ject Tube box MK11

Well there, we seem to have narrowed down the problem area. Try a SS phono stage.
Yes but that phono stage did not have the hum-rush problem. Could it be my cart? the Ortofon SPU Silver Meister?
02-26-13: Fromunda
Fosgate sig was the last addition. But I believe the hum was there before as well.

02-28-13: Fromunda
Yes previous phono stage was Pro Ject Tube box MK11.

High efficiency system? Check. New tube phono stage hum? Check. Previous tube phono preamp hum? Believe so. Alright, what am I missing?

Sure, you can try another cartridge if that's what you want to do.
I had a similar hum problem. I had a separate ground from the turntable and one from the tonearm, both were grounded to the phono stage (no ground wire ran to the amp from the phono). Then I switched the ground from the TT to the amp and left the ground from the tonearm to the phono. The hum disappeared.
how do you run a ground from the tonearm?
The one tonearm I have has the 5-pin DIN connector (the 5th wire connects to a metal tab that makes contact with the tonearm housing. I grounded that to the phono. My tonearm sits on a wood tonearm board (insulated from the plinth and motor). The motor is a DD and has an aluminum plinth. The plinth of the TT has a ground post that is grounded to the amp.

I can only speculate why it works on my table. Maybe some electrical engineer/technician could explain.