[arthur]

I've had the amp for over a year now and must say it's an incredible amp and, given the existing market, is worth EVERY penny (if not a lot more).

My only misgiving has been a hum coming from the amp that is audible at about 1 foot distance from the amp in a quiet room. there is also enough noise coming from the speakers when only the amp is on to be audible at almost 2 feet from the speakers.

i've always considered this the only negative with the amp but i have recently noticed that the noise from speakers and amp disappear during certain times of the day. it's not a ground loop in my stereo system since only the Stratos is grounded.

 the noise used to only be there in the afternoon,  but now it has switched to evenings. and what is even more disturbing is that during the noisy hours, when i put my ear within two feet of the electrical outlet i can hear it hum.                 Yes, i have tried shutting everything in my house down and using a different outlet (so pulling a dedicated AC line will probably not help any).

clearly this is not the fault of the amp or any of my audio gear... but then what can i do? how can i clean up the ac without having to spend thousands on something like PS 600?

i called the guy at mapleshade who swore that his $200 power strip "blows away" the multi thousand dollar power conditioners however he said that he does not think that his strip will take away any hum or anything like that.

realistically speaking the noise is not loud enough for it to account into the experience of hearing music (the noise from the outside during the afternoon makes it impossible to make any kind of a critical listening comparisons between evening and afternoon). my main concern is that the such interference might be negatively affecting the longevity of the equipment.

i would greatly appreciate any input.

PS. Hey Klaus I'm still saving up every penny i can to pitch for the Tempest but it's not happening at the speed that i would like... but i'm hanging in there and not loosing hope   .

[Ferdi]

HI Arthur, I know you said you do not have ground-loop hum. Just to be sure: do you have an antenna cable attached? I found that in my system that causes hum. I ended up using an ungrounded power cable with my (220V) Stratos.

A few other thoughts:
- Are you using a shielded power cable on the Stratos?
- Are you using a grounded power cable on the Stratos?
- Are you using shielded interconnects?
- Have you tried making your system as simple as possible and adding components back only later on? If your CDP has a variable output, you may be able to start from: CDP->Stratos->Speakers.
- What I found strange is that you are getting hum both from the amp(mechanical noise from the transformer, I assume) and the speakers (an electrical signal). Are you sure you are getting both of these?

The things above are just my quick thoughts. I stronly suggest you take this up with Klaus as well.

Good Luck!

[jcoat007]

I have an Odyssey HT-3 that I have had a consistent hum from the speakers.  You can hear it when you are about three feet away.  When playing music or watching movies it is not noticeable at all.  I do not have any hum coming from the HT-3 itself, just through the speakers.  I have had the unit plugged into a Richard Gray Power Conditioner and the wall outlet directly.  There was little or no difference in the hum either way.  

I also have Xtreme monos and there is no hum at all.

[Eduardo AAVM]

I agree with Ferdi, in my situation after much tries and error I found it was an antena connected to the power strip that caused that damn hum...

later I found that when I connected the audio outputs from my Philips DVD while the video out connected to TV also there was high pitched hum...

[arthur]

Ferdi,
my answer is pretty much 'yes' to all of your questions.
also i don't have any video or any other exteranl input coming into my system other than AC which is i think the source of my problems since nothing else would explain the fact that all of the noise decreases to almost silence during certain times of the day.  
i'm a bit tempted to try out the Mapleshade power strip but i don't think i will since the designer himself said that it will not solve my problem.  have any of you tried it or any other power conditioner to eliminate such blatant noise?

[Ferdi]

OK, try lifting the ground on the Stratos using a cheater plug (or some other convenient means).

I would check this with Klaus as well.

I have never had the need to try a power conditioner. Absolutely no experience with them.

Good luck

Edit: spelling

[macnewma]

I have the same problem with my Stratos.  I spoke to Klaus about it and he recommended lifting the ground.  I put a cheater plug on and it helped but didn't eliminate the hiss/buzz.

He also suggested that he might need to re-bias the amp and give a quick tune-up.  I haven't had the opportunity to do this, but I plan to in the near future.

I would suggest calling Klaus.  He will do everything within his power to help you out.

Max

[scottpretti]

I had some horrible problems with my power,  then I tried a BPT unit (balanced power).  Chris has may sizes at different price ranges  http://www.b-p-t.com/  I run a 2.5 with Bybees and I have to put my ear  next to the tweeter to hear a only a very slight hiss, almost nothing.   I had all kinds of noises coming from my system; hums, hisses, oscillating sounds- you name it.  All gone.   You can also check out Boulder Cable, they make a few  bybee adapters (cost less then a balanced power unit) that really clean up your power.  I run my three monos, pre/pro, cdp, and HTPC off the BPT.  I must say Chris at BPT has the best prices i found on balanced power equipment.

[arthur]

no, lifting the ground makes no difference. it is clearly a problem with my AC and not the amp. This amp is an absolutely stellar piece of equipment.  when i plug it into an outlet at my friend’s house there is no noise coming out of anywhere other than the normal barely existent low hiss from tweeters.
the funny thing is that i don't even think that my AC issues are degrading the sound when i'm actually playing music. my only concern is with making sure that my drivers don't wear out prematurely.

i wish someone would do a shootout of various AC conditioners. For example a shootout between the Mapleshade strip, Bolder Cable Bybee strip, PSAudio 600, and the top BPT unit.  i could contribute my dirty power line to really put them to a test  

[Ferdi]

Hi Arthur, then there is nothing else to do but have an electrician look at your mains. Maybe you do need a special filter/conditioning device after all.

Good luck!

Ferdi

[wreilly]

Have you ( can you ? ) check the polarity of the incoming power?

[gotmikey]

I had some hum coming from my stratos and narrowed it down to my television cable.  Even if you don't have any video cable connected to that room, I have found that cable ground loop hum in general somehow "leaks" into MY AC lines.  If you do have cable here is what I did and it might work for you as it worked for me.  I went to them main cable box, took a copper ground wire and secured one end to my cable splitter and the other to the actual steel box cover built into the house.  Anything that is securely grounded basically.  Voila, no mo hum!  It's worth the five minutes of work, even if it doesn't take out the hum.  At least you know your cable network is grounded.  Good searching!

[gotmikey]

I had some hum coming from my stratos and narrowed it down to my television cable.  Even if you don't have any video cable connected to that room, I have found that cable ground loop hum in general somehow "leaks" into MY AC lines.  If you do have cable here is what I did and it might work for you as it worked for me.  I went to them main cable box, took a copper ground wire and secured one end to my cable splitter and the other to the actual steel box cover built into the house.  Anything that is securely grounded basically.  Voila, no mo hum!  It's worth the five minutes of work, even if it doesn't take out the hum.  At least you know your cable network is grounded.  Good searching!

[Vince]

Had some hum coming from my Stratos, not from the speakers though. Never found out the cause, but solved it by using a medium size transformer, lowering the voltage from 125 to 115 V (For some reason we get 125V where I live) Just running the power through the transformer voltage unchanged has same effect, but my amp runs cooler on 115V.
 

[Eduardo AAVM]

There are some accesories intended to fix these problems at Audio Advisor, some look real interesting but I have not probe any of them yet, Any of you have ?

http://www.audioadvisor.com/store/productdetail.asp?sku=TRIBGG1&product_name=Ground%20Guard%201%20Ground%20Loop%20Eliminator

[arthur]

the polarity on my wires is accurate and i don't have any video signals coming into my stereo system. i only watch movies on a front projector (imaging is much better without a TV). And even then i unplug the S-video cable every time after i'm done watching a movie (which does bring down the noise by around 12db!!! even when the projector is unplugged!).

my apartment just has some VERY shoddy AC wiring. there is no central power shutoff switch so i don't dare to rewire/clean up the circuit breaker box   .  so i'm just going to go for a power conditioner. i already ordered one so lets see what happens.

 ... but hey if there are any of you out there in Los Angeles who are couragous enough to add a circuit braker into my box please let me know