[Lkdog]

I am not suggesting a regenerator. I am suggesting figuring out what is causing the problem and then addressing it directly. But to audiophiles that's no fun. Why would an audiophile spend money having a dedicated circuit put in when then can buy a new gadget and then swap it out for something different and purportedly better in a few years?

Sh!t. I just convinced myself I am not an audiophile.

For the record- the system is on its own newly installed line from the breaker box, but obviously shares the overall feed into the house with the usual stuff. Nothing else on this line except the system. Because it is random and not constant and not coming out of speakers one can rule out garden variety 60hz hum from dimmers, cable tv, etc.
As a guitar player I know 60hz hum inside and out.




The possible source of DC could be anything inside, or possibly outside the house. I wish it was as simple as when the dimmer was on, or when the refrigerator compressor kicked on, or the hair dryer or toaster was on, or somebody next door was using an electric leaf blower, etc.  I have read on the Van Alstine circle thread on his Humdinger that he says Plasma TVs are known to induce DC on the AC line they are plugged into. I do have a Pioneer Plasma on the line in my dual HT/2 channel setup. But the transformer hum happens when the TV is not even on also. 
It happens at 10 am, it happens at 6pm, it happens at 2 am. Who the fck knows. 

I would like it to stop. Wouldn't mind some additional line conditioning to lower noise floor along with it.
Yes, I am as probably as obsessive as the next guy or I wouldn't be on here with the rest of the people here who are all crazy TBH. 

[Doublej]

If it were in my system I would definitely like it to stop too. It sounds like it could be something outside the house like when someone else's refrigerator kicks in, UGH!. Quoting Dave C. from the linked thread, "Power company will usually come out for free. It's not unusual to have issues with power delivery that can be fixed for free as it is often in their equipment outside the house. I don't think you'll lose anything by having them come out to inspect."

You'll need the power regenerator anyway to achieve your other goals so then it's a matter of if the problem goes away with a regenerator what extra benefit might you get by addressing the source of the problem.

If the power company needs to come inside the house and charge you to identify the problem, I think that's fair. If you called an electrician to figure out what was wrong, they would charge you and then tell you if the problem was identified to be outside the house you need to call the power company.

Good luck. Power problems seem far tougher to determine root cause than a channel problem.

[Stercom]

If it's a hum, not a buzz, then it's NOT DC on the line or a ground loop. Most likely at some point your transformer was tightened too tight (or possibly dropped) causing the insulation within it to break.  Loosen the transformer and place some sorbothene or other type of material under it. Then tighten it backup snug, don't over-tighten it again! Transformer cores are constructed by stacking layers of thin iron laminations, separated by a thin non-conducting layer of insulation. When the core becomes magnetized, the magnetic field vibrates between the adjacent plates, stretching and squeezing the adhesive and insulation between them causing the hum.

[Lkdog]

If it's a hum, not a buzz, then it's NOT DC on the line or a ground loop. Most likely at some point your transformer was tightened too tight (or possibly dropped) causing the insulation within it to break.  Loosen the transformer and place some sorbothene or other type of material under it. Then tighten it backup snug, don't over-tighten it again! Transformer cores are constructed by stacking layers of thin iron laminations, separated by a thin non-conducting layer of insulation. When the core becomes magnetized, the magnetic field vibrates between the adjacent plates, stretching and squeezing the adhesive and insulation between them causing the hum.

Its more like a buzz. The first post has a video of it you can listen to.
https://drive.google.com/file/d/1rJIvYy8xoZmhh_0AdhvshX_0bg3-1-Ol/view?usp=sharing
I am talking to Klaus today and will report back.

I appreciate everyone's help. I am sure it will get worked out. 

[Stercom]

Sounds like transformer hum to me. Some sorbethene feet placed under the transformer resolved it for me on a number of amps over the years. Looks like Klauss says its DC on the line. Will be interesting to see how this gets resolved. I'm certainly not saying I know more than Klauss just relaying my experience. Good luck. 

[DaveC113]

Wow, lots of replies!

I thought I'd mention that most power conditioners won't solve a DC offset issue, including the SurgeX devices I refurb and modify. They do have the same Zero-Surge, non-MOV technology, plus a very good EMI/RFI filter and some other features that will shut off power if voltage gets too high or low, etc. They work great for big amps too, the design is intended for industrial applications and is used in some very high end installations including Carnegie Hall, NASA uses them, as does Boeing and others... so these are really good for surges and emi/rfi reduction but NOT DC offset.

Transformers may work, but they themselves might hum with dc offset too. And they are $$$.

Regens can work very well but are also $$$ and results of this, and any other AC power filters, depend on how much noise you currently have.

Another option for reducing AC noise is Furutech NCF products. A single NCF receptacle can make a big difference!

I'd recommend calling the power company if the issue persists. It may be at your neighborhood trafo and the cause my be in a neighbor's house. It's not for sure an issue in your own home.

[Lkdog]

Going to try the Van Alstine Humdinger to see if that clears up the DC issue.

When going straight into the wall it still happens.
Might be a little less when on the Tripplite Isobar.
Actually sounds a little better through the Tripplite Isobar upon closer listening which does some very basic line filtering.
A little edgier straight from the wall.

Will report back.

Thanks again to all.

[Bullitt5094]

I've had a ton of equipment through my system over the years. The only component that's ever had any noise problem was the Kismet amp I purchased. I did everything Klause asked of me to fix it including replacing the PS Transformer. Finally returned it and was charged restocking, credit card fees and basically everything else he could think of to not return my money. Good Luck!

[klaus@odyssey]

Bob Watson,

Let me just say that you're welcome that I took back the amp after all the crap I went through...works great,  doesn't work,  works great agaion,  sent out parts to exchange because you can do it,  works great again,  then it doesn't (as per phone and emails).....so I decided to take it back to stop this nonsense and nope,  we don't have restocking fees,  but you sure as hell had to pay the cc charge and shipping....and you're also welcome to have kept the gear that I got you for a big discount,   and no,  that's still not the whole story, and let's leave it at this........however,  I noticed that you're smearing me all over the net now,  nice going dude..... 

[Doublej]

Going to try the Van Alstine Humdinger to see if that clears up the DC issue.

When going straight into the wall it still happens.
Might be a little less when on the Tripplite Isobar.
Actually sounds a little better through the Tripplite Isobar upon closer listening which does some very basic line filtering.
A little edgier straight from the wall.

Will report back.

Thanks again to all.

This thread reminded me that I should remove the Tripp lite Isobar from my modest system and plug everything into the wall. I don't have enough outlets to do that so I did the next best thing which is to plug everything into a Wiremold power strip. I agree with you. i think it's a little less edgy with everything plugged into the Isobar.

[klaus@odyssey]

Yes,  the Isobar takes away some of the top end dynamics...

[Lkdog]

Yes,  the Isobar takes away some of the top end dynamics...

That could very well be. It sounds a hair softer through the Tripp Lite.
The recording that actually sounded a little edgier is poorly mastered and too harsh to begin with.

If the Van Alstine humdingers work, then I need to try a better surge/line filter.

[Lkdog]

I've had a ton of equipment through my system over the years. The only component that's ever had any noise problem was the Kismet amp I purchased. I did everything Klause asked of me to fix it including replacing the PS Transformer. Finally returned it and was charged restocking, credit card fees and basically everything else he could think of to not return my money. Good Luck!

 

Take it offline.

Just trying to troubleshoot an issue that actually happens <1% of the time in my AC line in my house, in my neighborhood power grid.
Could be a neighbor's garage door opener for all I know.

Comes with the territory in this hobby. Not a big deal and will get worked out.

Love the amps. And I have listened to a shit ton of high end equipment and live and studio music over the past 40 years. The best system I have had by fair margin now which maybe isn't saying much but it actually suspends disbelief on good recordings. 
Have listened to more music this past two months than in previous five years. That is the whole idea.

I don't mind working out little problems.

[Tyson]

Also try shorting the inputs on the amp and see if the problem persists.  If it does then it’s your AC or even just the amp itself.  But if the problem stops then it’s almost certainly a grounding differential between the amp and you preamp and/or source components. 

[SJ David]

"...

Comes with the territory in this hobby. Not a big deal and will get worked out.

Love the amps. And I have listened to a shit ton of high end equipment and live and studio music over the past 40 years. The best system I have had by fair margin now which maybe isn't saying much but it actually suspends disbelief on good recordings. 
Have listened to more music this past two months than in previous five years. That is the whole idea.

I don't mind working out little problems."

I applaud your attitude and calm approach to this.

I live in a house built in 1957 and as far as I know the electric system has not been touched other than new breakers. All to code circa 1957. The wall outlets are all 20 amp with hot-and-return two wire connection.

I started a project of replacing outlets last weekend. On one circuit I cut the breaker. All lights, LED displays, etc went dark as expected. Put a DMM on the circuit as a double check and found that there was still voltage reading on the line. About 38 volts. But the breaker was open. Did some further testing to confirm no current would flow while setting the new outlet. So I have some "phantom" voltage on the line. Never dealt with this before in my DYI experience.

As with the OP I am trying all sorts of things from reading about this online. Differing opinions and solutions abound but the mystery persists. This stuff happens.

-David

[Lkdog]

OK, Update for those interested or who might have a similar issue in their AC line.

I got the a pair of AVA Humdingers. They have two receptacles in them so I tried one to begin with.
I was not sure if they would get hot, or stressed with both the Kismets plugged in.
The one is running cool and I have been running music and video for a couple days so no worries there.

So far so good after two days...............    





Will let you know if that changes, but usually I would hear an episode of DC hum even if just for a little bit every day or every other day.
And if you were wondering- no impact on sound.

[jmolsberg]

^ nice. good to hear

[Will]

This is more or less a repost, but I offer it in case I can save anyone time and trouble...

I had a hum issue with the transformer in my Tempest - and still had the hum even with the mu shielded transformer.   

It turned out the transformer hum was caused by DC in the lines. A (now discontinued) PS Audio UPC-200 Humbuster made the hum disappear.

Klaus was incredibly caring, and went WAY beyond the call of duty trying to solve this issue.

Thank you Klaus!

[Saturn94]

OK, Update for those interested or who might have a similar issue in their AC line.

I got the a pair of AVA Humdingers. They have two receptacles in them so I tried one to begin with.
I was not sure if they would get hot, or stressed with both the Kismets plugged in.
The one is running cool and I have been running music and video for a couple days so no worries there.

So far so good after two days...............    





Will let you know if that changes, but usually I would hear an episode of DC hum even if just for a little bit every day or every other day.
And if you were wondering- no impact on sound.

Yay! 

[Lkdog]

Final update.

Problem seems to be solved. One week and no hum. 

Highly recommend to try the AVA Humdinger for this particular issue.