Doepfer

I guess this explains why my Doepfer portable cases are so quiet.  
The power supply is bolted to a piece of fibreboard, which probably 
doesn't resonate as much as the metal.

--- In Doepfer_a100@yahoogroups.com, Florian Anwander 
<Florian.Anwander@c...> wrote:
> Hi Pierre
> 
> > Quick question: do your PSUs make an audible buzz/hum?  
> 
> Yes it does. It is - as the others said - a mechanical hum from 
the 
> transformer. If you have a standard power supplies mounted to the 
rear 
> side of the rack, the hum will be louder than from a modul like 
power 
> supply, because the back plate of the housing works as resonator.
> 
> To me this hum is quite annoying, because I always have to switch 
off 
> the modular when I do microphone recordings - and now guess where 
the 
> powerswitch is located and how reachable it is...
> 
> A solution might be to mount the powersupply on a foamed rubber 
plate 
> and mount this rubber plate to the housing.
> 
> Florian