[kothganesh]

   
Yes, there can be noise from other appliances that creep into the power and affect your audio gear. The biggest culprits are usually refrigerators, air conditioners, and dimmer switches. Unfortunately there's no good fix for this. You can try plugging into an outlet that's on a different breaker.
 

 
 

  Only things I can think of are the high current appliances drawing too much power if the line is shared or if the appliance is near by causing magnetic field(inductive appliance) which will induce noise.  

 
 

Yes it could be your AC, any large appliance, can create electric "grunge", look for a good power station device I use a Power Wedge on my main rig and a Monster on my Head Fi setup.

Thanks for the opinions. I am going to shift the setup to a different room to see if the situation persists.

 

[Armaegis]

  How would the noise be created from the appliance to go to the amp?  The appliance is drawing power separately.  It's possible that the amp's gain is too high for the headphones.

 
In theory the power lines in your home should never waver from 0V and 120V (or whatever your regional voltage is). In reality, there's slight fuzziness. Ground may not be perfectly 0V, and the live wire may not be perfectly sinusoidal nor reaching the desired peaks. There could also be DC offset. While the specific reasons are beyond the scope of this thread, the simplified explanation is that some devices inherently draw power in a very noisy fashion and this grunginess sneaks back into the household powerlines and takes them away from ideal.
 
Sometimes that grunginess itself is what causes noise in the amp. Sometimes it's because the power is no longer "perfect" and the amp reacts poorly to that. Oftentimes a simple cheap surge protector won't do anything at all the combat that (most of those that do have filters are only good for the ultrasonic content).
 
Now, amps that have high gain suffer both from amplifying noise that's coming in on the input signal, or from the inherent amp noise floor (which can also be affected by dirty power).
 
 

  What happens is the following: When I choose the Speaker Input set that is connected to the HE 6, everything is fine for about half an hour. Music is distortion free and in between songs, there is dead silence. After about half an hour, I get the noise sometimes during the song, sometimes between two songs. Its completely random and will sometimes vanish for a song or two. After an hour or so the noise is longer lasting. I turn the volume all the down to zero and the noise persists.

 
Without knowing the specifics, this could be lousy power in the house, maybe an amp issue. If it's an old speaker amp, it might be some caps that are near the end of their life. Maybe something temperature related once the amp warms up. Just guessing here.

 

[gjc11028]

How would the noise be created from the appliance to go to the amp?  The appliance is drawing power separately.  It's possible that the amp's gain is too high for the headphones.

https://www.youtube.com/watch?v=H9GWdMm6qs0&feature=youtu.be

 

[SilverEars]

https://www.youtube.com/watch?v=H9GWdMm6qs0&feature=youtu.be

I don't understand a word that was said, can you tell me where he is tapping into to pick up the noise on the scope?  What is the signal on the scope representing?  what the scale of the scope is?   

 

[wuwhere]

I believe its been stated here that SS amps don't need the resistor for impedance matching since they don't have output transformers. Well some SS amps still use output transformers, like the McIntosh brand. Their MC452 model has output transformers.

 

[Theogenes]

Just a thought, but if you've got a cellphone or tablet near any of your gear (or your headphone cables), you can get some pretty funky interference. I used to get it on my two-channel sometimes, and it drove me crazy figuring out what it was because it was intermittent-- until I realized it was from setting my phone on top of my gear. Don't know if that's your issue, but it's a super easy theory to test...

 

[gjc11028]

  I don't understand a word that was said, can you tell me where he is tapping into to pick up the noise on the scope?  What is the signal on the scope representing?  what the scale of the scope is?   

the signal is showing the noise in the power line from the bulb.  do not know the scale.  you can email gilbert at blue circle audio and ask, he is always happy to answer questions and i am sure would be happy to explain what he was doing.  

 

[purplegoat]

HE-6 is sounding slow on my Denon PMA-750. It's old and I don't think it's been serviced in awhile.. Does anyone know if repairing an old amp will make it faster or is that an inherent advantage to newer amps?

 

[kothganesh]

Hey guys,
 
I ordered both the focus and the focus A pads. Now I completely forgot which was the recommended pair? Help please... thanks

 

[Happy Camper]

This is a good opportunity to remove any bias and just try each. Thing with pads are they need to be broken in to determine their impact. A new pad is not what you will live with. Just throwing that out there.

 

[preproman]

Yup pick for yourself.  I know I did.

 

[hennessys]

HE-6 is sounding slow on my Denon PMA-750. It's old and I don't think it's been serviced in awhile.. Does anyone know if repairing an old amp will make it faster or is that an inherent advantage to newer amps?

That Denon is worth to check with the vintage guys. I'm just spending my honeymoon with a Technics from the 80’s and i love every minute of it.

 

[Armaegis]

  HE-6 is sounding slow on my Denon PMA-750. It's old and I don't think it's been serviced in awhile.. Does anyone know if repairing an old amp will make it faster or is that an inherent advantage to newer amps?

 
Too many variables and generalizations to offer any sensible advice.
 
In general, old amps will need to have their capacitors replaced and probably some deoxit on the connectors and pots. As for how "old" amps will sound... *shrug* my completely out-of-thin-air guess based on no information whatsoever is that fixing up the old amp will not make it "faster".

 

[purplegoat]

Sorry for being vague. I guess my question is can an amp's SQ degrade while still being able to play music?

 

[Armaegis]

Absolutely. Loss of power/headroom is an obvious one. Distortion can also increase quite a bit when your components are no longer in spec.