[dminches]

It definitely sounds like a ground problem in your electrical system.  Do you have cable TV?  Those systems are notorious for ground loop issues.  If there is any way to disconnect your cable connections that would tell you if that's the culprit. 

 

[Silent One]

Thanks for sharing. Will research and listen up later tonight.

 

[Silent One]

Quote:

It definitely sounds like a ground problem in your electrical system.  Do you have cable TV?  Those systems are notorious for ground loop issues.  If there is any way to disconnect your cable connections that would tell you if that's the culprit. 

+1
The mere touching the coax will give it up (grounding issue or no?).

 

[Red Jacket Mike]

     Quote:

That the hum goes away when you lift the ground tells me that it's not your equipment.  The last time I had one of these problems, I started swapping interconnects and then the problem went away.  I got a few pair of the Cardas braided interconnects and my hum went away.  For me there was some mismatch between gear and the braided interconnects solved the problem.
 
It may be worth the time working on to solve because you tend to hear more with headphone amps.  You may want to try the cheapest interconnects possible from Radio Shack just to see if a change-up in interconnects help. 
 

 
Actually, I mentioned in my last post that I have now determined that lifting the ground does not eliminate the hum; I thought it did at first, but after checking it out further, I can still hear it.  I have also tried several different pairs of interconnects, but that's not the problem since the hum persists even when the Woo is plugged directly into the wall with nothing else connected except headphones.
 
Quote:

It definitely sounds like a ground problem in your electrical system.  Do you have cable TV?  Those systems are notorious for ground loop issues.  If there is any way to disconnect your cable connections that would tell you if that's the culprit. 

No, no cable TV.  I have satellite TV, but in a different part of the house, and on different circuits.  
 
Quote:

+1
The mere touching the coax will give it up (grounding issue or no?).

I'm almost positive it is coming from the amp, and is not a house wiring, etc., issue.  Wherever I plug the amp in, even in my shop (which is a separate building behind my house where I work) the hum is there if I listen closely.

 

[mikemalter]

Quote:

     Quote:

That the hum goes away when you lift the ground tells me that it's not your equipment.  The last time I had one of these problems, I started swapping interconnects and then the problem went away.  I got a few pair of the Cardas braided interconnects and my hum went away.  For me there was some mismatch between gear and the braided interconnects solved the problem.
 
It may be worth the time working on to solve because you tend to hear more with headphone amps.  You may want to try the cheapest interconnects possible from Radio Shack just to see if a change-up in interconnects help. 
 

 
Actually, I mentioned in my last post that I have now determined that lifting the ground does not eliminate the hum; I thought it did at first, but after checking it out further, I can still hear it.  I have also tried several different pairs of interconnects, but that's not the problem since the hum persists even when the Woo is plugged directly into the wall with nothing else connected except headphones.
 
Quote:

It definitely sounds like a ground problem in your electrical system.  Do you have cable TV?  Those systems are notorious for ground loop issues.  If there is any way to disconnect your cable connections that would tell you if that's the culprit. 

No, no cable TV.  I have satellite TV, but in a different part of the house, and on different circuits.  
 
Quote:

+1
The mere touching the coax will give it up (grounding issue or no?).

I'm almost positive it is coming from the amp, and is not a house wiring, etc., issue.  Wherever I plug the amp in, even in my shop (which is a separate building behind my house where I work) the hum is there if I listen closely.

If it is only from the amp, that is a separate issue.  Are you hearing the hum in the phones, or are you hearing it from the equipment?  And, is it only from the amp?
 

 

[Red Jacket Mike]

     Quote:

Originally Posted by mikemalter /img/forum/go_quote.gif
 
If it is only from the amp, that is a separate issue.  Are you hearing the hum in the phones, or are you hearing it from the equipment?  And, is it only from the amp?

Only from the amp.  I hear it in the headphones, not from the equipment directly.  It is equally present with my HD800s through the high impedance jack, and with my Denons through the low impedance jack.

 

[dminches]

Have you tried using different tubes?

 

[mikemalter]

Quote:

     Quote:

Originally Posted by mikemalter /img/forum/go_quote.gif
 
If it is only from the amp, that is a separate issue.  Are you hearing the hum in the phones, or are you hearing it from the equipment?  And, is it only from the amp?

Only from the amp.  I hear it in the headphones, not from the equipment directly.  It is equally present with my HD800s through the high impedance jack, and with my Denons through the low impedance jack.

So you have a DAC, and if you put your ear near it there is no humming?
 
Do you hear the hum only if there is no music playing?  If so, how high do you have to turn up the volume to hear it?

 

[Red Jacket Mike]

      Quote:

Have you tried using different tubes?

    Yes--tried different power tubes and rectifier; no difference.  Hum still present.
Quote:

So you have a DAC, and if you put your ear near it there is no humming?
Do you hear the hum only if there is no music playing?  If so, how high do you have to turn up the volume to hear it?

 
Well, all pieces of gear will make some noise if you get your ear close enough, but this hum is not like that; it is audible only through headphones, and it is the same level no matter where the volume control is set--even completely off.
 
I have to stress again that this is a VERY faint hum--the room has to be very quiet otherwise, and I have to strain to hear it at all.  But, it would be better if it weren't there.  And it is definitely coming from the amp, and from the amp alone. 

 

[mikemalter]

Ok, well if it is very faint, then it probably is no big deal then.
 
Can you hear the transformers hum when you put your ear close to the amp?

 

[Red Jacket Mike]

I used to be able to hear that, but I purchased some heavy brass weights from Mapleshade; one large 3 lb. weight goes on top of the power supply transformer, and 2 smaller 1.5 lb. weights go on top of the two transformers on the amp itself; afterwards, that particular noise became just about nonexistant.
 
I have the amp on brass footers, which also helps with noise, vibration, and air circulation.  This last tiny hum I'm hearing through the headphones is the last little bit of noise I'm trying to eliminate.  
 
Here's a photo:

 

[Driftwood]

The hum could be caused by a DC voltage on your AC power, if that is the case, something like the PS Audio Humbuster could help. There are probably less expensive ways of solving the same problem though...

 

[Silent One]

How do you like the installment of the brass footers under the 6SE? Was any improvement in sound small or easily noticed?

 

[Red Jacket Mike]

Improvement in sound, not really.  But vibration was noticeably reduced, even eliminated.  In my experience, often what is perceived as equipment hum is caused by very small vibrations, especially with tube gear.
 
The amp is also much cooler to the touch after running for a few hours.The brass footers afford 1.5 inches of clearance, and possibly they are pulling some heat from the amp's chassis.  The equipment rack is also a Mapleshade unit, with very thick, heavy slabs of oak for shelves.  This helps with vibration, as well.  Here's a photo of the entire setup:
 

 

[dminches]

Here's something else to try.  http://www.ciaudio.com/products/XDC2  This is a product which is used to clean up the power, as someone else suggested.