# Problem with Powerbase **URL:** \ **Category:** Power Components\ **Created:** [December 19, 2013, 6:52pm UTC](https://forum.psaudio.com/t/problem-with-powerbase/705 "2013-12-19T18:52:02Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![Elk](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/elk/32/1240_2.png) [@Elk](https://forum.psaudio.com/u/Elk)\ **Post date:** [December 21, 2013, 7:48am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/21 "2013-12-21T07:48:57Z")
A waveform has DC offset when its crossover points are other than zero. That is, the entire waveform is moved up by the presence of DC current in the signal. When there is no DC offset (good) the waveform is centered around 0 and goes positive and negative from there. It is typically caused by an electrical mismatch in the recording chain. This is typically inaudible. However, in this discussion it is probably caused by a ground loop with a difference in potential of multiple grounds. In this latter case, you can hear a low level hum at 60Hz (and its harmonics such as 120Hz, 200Hz, etc.). The upper waveform exhibits DC offset: ![](http://wiki.audacityteam.org/w/images/d/df/DC-offset.png) ---
**Author:** ![Paul](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/paul/32/6_2.png) [@Paul](https://forum.psaudio.com/u/Paul)\ **Post date:** [December 21, 2013, 9:18am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/22 "2013-12-21T09:18:22Z")
@maniac The P10 will remove DC offset on its output. It has a fairly sophisticated DC servo system built in that should remove any DC component on the output. ---
**Author:** ![Maniac](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/maniac/32/216_2.png) [@Maniac](https://forum.psaudio.com/u/Maniac)\ **Post date:** [December 21, 2013, 9:53am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/23 "2013-12-21T09:53:21Z")
@admin Thanks Paul, I did not know about it (maybe good tip to add it to Powerplant specs 🙂 ) I also have transformer hum problem on all my Electrocompaniet devices. EC is using some FTT technology (floating transformer) - could it be that this technology does not like regeneration from the P10? It’s audible on Sine and also Multiwave, but to be honest it’s slightly buzzing also when directly connected to the wall (that’s why I though I might have DC offset on my wall socket). ---
**Author:** ![wglenn](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/wglenn/32/172_2.png) [@wglenn](https://forum.psaudio.com/u/wglenn)\ **Post date:** [December 21, 2013, 10:36am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/24 "2013-12-21T10:36:56Z")
So I guess the next question is does it hum when it is plugged into the P10 but disconnected from the audio chain otherwise eliminating the ground loop? Guess you’ll have to “wait till your ship comes in.” ;)) ---
**Author:** ![beefalo](https://avatars.discourse-cdn.com/v4/letter/b/ce73a5/32.png) [@beefalo](https://forum.psaudio.com/u/beefalo)\ **Post date:** [December 21, 2013, 10:40am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/25 "2013-12-21T10:40:57Z")
Thanks elk I understand now . I always thought ground loops looked like a smaller wave over the signal . But how does dc appear to be there in the first place ? Is this a change in the potential from output to input of different devices with separate PSU , s ? ---
**Author:** ![beefalo](https://avatars.discourse-cdn.com/v4/letter/b/ce73a5/32.png) [@beefalo](https://forum.psaudio.com/u/beefalo)\ **Post date:** [December 21, 2013, 10:43am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/26 "2013-12-21T10:43:18Z")
My P5 makes a low buzz sound at changing intervals . It does this weather it is used or not and from wall or ups power. It’s very low . ---
**Author:** ![Frode](https://avatars.discourse-cdn.com/v4/letter/f/5f8ce5/32.png) [@Frode](https://forum.psaudio.com/u/Frode)\ **Post date:** [December 22, 2013, 6:29pm UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/27 "2013-12-22T18:29:25Z")
The noise is back. It is worse during the night, but I think this is partly due to that the background noise is less prominent. I will try to run the subs through the DC filter and see what happens. ---
**Author:** ![wglenn](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/wglenn/32/172_2.png) [@wglenn](https://forum.psaudio.com/u/wglenn)\ **Post date:** [December 22, 2013, 7:22pm UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/28 "2013-12-22T19:22:52Z")
Unhook the connections other than the AC to check for ground loops? ---
**Author:** ![Frode](https://avatars.discourse-cdn.com/v4/letter/f/5f8ce5/32.png) [@Frode](https://forum.psaudio.com/u/Frode)\ **Post date:** [December 23, 2013, 9:47am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/29 "2013-12-23T09:47:57Z")
> Unhook the connections other than the AC to check for ground loops? Yes, I will try a cheater plug when I come back from my cabin in the Norwegian mountains :) The strange thing though is that the presence is irregular, at least wrt. intensity. ---
**Author:** ![Elk](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/elk/32/1240_2.png) [@Elk](https://forum.psaudio.com/u/Elk)\ **Post date:** [December 23, 2013, 10:21am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/30 "2013-12-23T10:21:32Z")
This suggests ground loop to me. The voltage potential varies with the integrity of the ground, especially in cold weather. I find the winter is when ground loops appear. (It is currently 0F/-18C here.) ---
**Author:** ![wglenn](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/wglenn/32/172_2.png) [@wglenn](https://forum.psaudio.com/u/wglenn)\ **Post date:** [December 23, 2013, 10:41am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/31 "2013-12-23T10:41:24Z")
> frode said: when I come back from my cabin in the Norwegian mountains Wow, that sounds like a James Bond Christmas location when you are from Ohio! ---
**Author:** ![Frode](https://avatars.discourse-cdn.com/v4/letter/f/5f8ce5/32.png) [@Frode](https://forum.psaudio.com/u/Frode)\ **Post date:** [December 23, 2013, 11:48am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/32 "2013-12-23T11:48:02Z")
> Wow, that sounds like a James Bond Christmas location when you are from Ohio! Hehehe. Here is a little teaser: ```
Attached files
``` ---
**Author:** ![wglenn](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/wglenn/32/172_2.png) [@wglenn](https://forum.psaudio.com/u/wglenn)\ **Post date:** [December 23, 2013, 11:52am UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/33 "2013-12-23T11:52:48Z")
Wow. Just, wow. =D\> ---
**Author:** ![wglenn](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/wglenn/32/172_2.png) [@wglenn](https://forum.psaudio.com/u/wglenn)\ **Post date:** [December 23, 2013, 12:10pm UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/34 "2013-12-23T12:10:30Z")
Though that I would share Ohio in winter. It’s a little drab this time of year but we make do! Attached files [![](https://sea1.discourse-cdn.com/flex015/wp-content/uploads/attachments/65344=2400-d8a424be1001f451d51c2dfdd7858a.jpg "/FileUpload/52/d8a424be1001f451d51c2dfdd7858a.jpg")](https://forum.psaudio.com/wp-content/uploads/attachments/65344=2400-d8a424be1001f451d51c2dfdd7858a.jpg) ---
**Author:** ![Frode](https://avatars.discourse-cdn.com/v4/letter/f/5f8ce5/32.png) [@Frode](https://forum.psaudio.com/u/Frode)\ **Post date:** [December 23, 2013, 1:24pm UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/35 "2013-12-23T13:24:55Z")
> Though that I would share Ohio in winter. It's a little drab this time of year but we make do! I think this really shows the extremeties :) For a Norwegian this must be the perfect advert for a hot summerhoilday! ---
**Author:** ![wglenn](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.psaudio.com/wglenn/32/172_2.png) [@wglenn](https://forum.psaudio.com/u/wglenn)\ **Post date:** [December 23, 2013, 1:58pm UTC](https://forum.psaudio.com/t/problem-with-powerbase/705/36 "2013-12-23T13:58:00Z")
Yes, indeed. If Ohio really looked like that I would probably never leave. [Previous page](https://forum.psaudio.com/t/problem-with-powerbase/705.md?page=1)