PLAN B analog blog

Hi, 
I had this problem (hum coming from audio out of my M15) after adding 
a certain module to my rack from another manufacturer. I removed the 
module from the power bus and the problem disappeared. I have since 
placed the module that was causing the problem in another rack with a 
separate power supply. Everything is fine. If you have other modules 
on your power bus. I would recommend disconnecting each module 1 by 
1, (ie: power rack down, remove a module, power rack up, listen to 
M15 and so on...) to determine whether there is something on the bus 
that may be inducing the hum. 

Regards, 
Adam 

--- In PLAN_B_analog_blog@yahoogroups.com, "dematteoanthony" 
<dongchi1@...> wrote:
>
> i purchased a model 15 used recently.
> 
> i am experiencing what sounds like a ground hum.
> 
> any suggestions would be much appreciated.
> 
> i am using the doepfer d.i.y power supply #1 i believe, its the one
> with 2 busboards.
> 
>  the case is made of wood w/ metal rails.
> 
> i have unhooked all other modules and tried powering the module as 
far
> away from the power supply as possible w/ no luck.
> 
> unfortanettly this is the only analog osc i have so i cant tell if 
its
> an issue w/ the power or the module itself.
> 
> i know its not the electrical in my room as i have brought the 
system
> to other places and received the same results.
> 
> any suggestions will be greatly appreciated.
> 
> thanks, tony
>