Search Buy Sell Learn MyPage

Learn > Forums > Tech talk > 1302916061  Start New Thread | Log In |

How Much DC is OK on a Power Line?

The other night my Classe amplifiers started producing a substantial mechanical hum. Classe told me that it was likely from DC on the power line. The hum was there even when the preamp was switched to standby, and even when I plugged the amps into different sockets. My questions: 1) how much DC on the powerline does it take to cause problems with audio equipment? 2) How does DC get into the AC signal on the power line? 3) Do the power companies have any spec they need to acheive for maximum DC? 4) Or is it more likely appliances within my house causing the DC. Thanks, Peter Peter_s  (System | Threads | Answers | This Thread) 04-15-11

Responses (1-35 of 35)

Click title to read one, or click date to read all below it. 04-16-11   Dc can come from your neighbors on the same feed as you....i ...   Larryken 04-16-11   The ps audio humbuster iii is working well in my system. it ...   Hifiman5 04-16-11   Peter, what model classe amp do you have ? a lot of later p ...   Gbart 04-16-11   Whould a power regenerator (purepower, ps audio) remove the ...   Pcoombs 04-16-11   Thanks gbart. i'm using classe omega amplifiers. i just me ...   Peter_s 04-16-11   Power regenerators do not remove dc. i use a ps audio premi ...   Hifiman5 04-16-11   I've been told that a buzz/hum from an amp can be caused by ...   Pcoombs 04-16-11   By the way, i'm using an environmental potentials home surge ...   Peter_s 04-17-11   Oh - and the question still remains - how much dc offset is ...   Peter_s 04-17-11   Pcoombs, harmonic distortion and dc are two different phenom ...   Gbart 04-23-11   I struggled with this issue for quite some time a couple yea ...   Rayooo 05-18-11   It is my understanding you cannot measure dc on the ac mains ...   Jea48 05-19-11   blocking mains dc offset   Jea48 08-16-11   Jea48, its easy to measure dc on top of ac if one uses a flu ...   Casouza 08-18-11   Most hum on power transformers is caused by dc on the power ...   Liguy 08-18-11   Does it matter, since the power supplys converts to dc anywa ...   6550c 08-19-11   http://sound.westhost.com/articles/xfmr-dc.htm#dc1 quote ...   Jea48 08-19-11   It matters if you don't want your power supply transformer t ...   Liguy 08-23-11   ^^^give me your address and i will send you a royality fee.. ...   6550c 08-24-11   6550, that is exactly the type of response i would have exp ...   Liguy 12-11-11   Say what no dc is best.   Ebm 12-11-11   Nothing that an isolation transformer can't fix. all my lo ...   Magfan 12-15-11   I have to take umbrage with the quote above. unless there is ...   Atmasphere 12-15-11   Not sure what a center-tap on the primary would have to do w ...   Jea48 12-15-11   Hmm. so, with the ac line having one side at ground, there's ...   Atmasphere 12-16-11   What does one ac line conductor, (neutral conductor), of the ...   Jea48 12-16-11   Well jim, i'm certainly open to finding out i've been wrong ...   Atmasphere 12-16-11   Ralph, i am not dismissing what you are saying about odd ha ...   Jea48 04-12-12   Gbart, could you make a dc line filter / blocker for me? if ...   Sbrownnw 04-14-12: Jea48 Harmonics. www.fluke www.psihq Is DC offset the product of harmonics? . Jea48  (Threads | Answers | This Thread) 05-04-12   My balanced power conditioner (isoclean) was humming/buzzing ...   Psag 06-01-12   Forgot to post that @gbart built me a very nice custom dc bl ...   Sbrownnw 06-29-12   Gbart, would love a dc blocker as well if you're willing:) i ...   Fmj 06-30-12   Gbart, would you please send me an email to actusreus13@hotm ...   Actusreus 07-02-12   Actusreus, i sent you an e-mail message. chris, you can re ...   Gbart

Post your response

Subject Your response No html, but you may use markup tags Username Members only Password