Can (defective) PSU affect quality of sound card output?

[Stefan1971HH]

Hello, 

the sound of my Asus Xonar Essence STX, connected to an Edifier 2.1 Box Set, 
has once been brilliant. Recently, the sound has increasingly lost dynamics 
and turned more and more "flat" and lifeless. 

Is it possible, that this caused by an unstable power supply unit (since other things, 
that may point to this, such as temporarily irresponsive or "disappearing" HDs, 
happened in the same time)? 

Or could power supply problems only lead to the card not working at all? 

Thanks

[Stefan1971HH]

11 hours ago, sandyk said:

 

How is the internal Asus soundcard connected to it,(Coax SPDIF for example)  and what is used to power the Edifier 2.1 ? 

 

 The Card uses a Molex connector, the box set gets external power (not from the PSU)