Nuforce STA200

aysancorluhan,, I already have the STA200, and the truth is worrying about it blowing up is the last thing I am doing.  I have not popped the hood to look myself, but it sounds like you are saying it is not fuse protected, which seems unusual.
 
While I am not currently thinking about new hard to drive speakers, I was really wanting someone to provide their input (thank you jl35) regarding the sound quality differences between the STA200 and a Parasound A21.  For example, does one image better than the other, better separation of instruments, anything else at all you can relate.

This amp produces no more power into 4 ohms than into 8 ohms.
Sensitivity is 0.45V for full output.
Gain is 35dB.

Very sensitive to source voltage and speaker load. At 51K ohms input impedance and the high input sensitivity a good candidate for a passive. Maybe try to set a stop on the passive pre so that volume can't be turned such that the degree of attenuation becomes too low overdriving the input stage. 

I will be using my STA200 with caution!

mesch, in layman’s terms, please explain exactly what are you being cautious about? Are you worried about the amp being driven into oscillation?  How does the fact that the amp produces the same power at 8 and 4 amps create a potential problem? If neither of these are the concern, what is the worry? Thanks in advance.

Here's a bump to mesch, or anyone else.  We have a first time poster declaring his amp blew up, and mesch stating he will use his amp with caution.  I am not savvy enough to understand or otherwise translate from above what "the degree of attenuation becomes too low overdriving the input stage" means or how it creates a situation that can be hazardous to the amplifier.  Since it has been brought up as a potential danger, lets hear what the danger is?  There are not that many posts on A'gon where using an amplifier for its stated purpose can create a potentially dangerous situation, that perhaps an amplifier has been built without normal protections built in, since this has now been brought up, lets hear the background behind it and potential danger.  Thanks in advance.

"At 51K ohms input impedance and the high input sensitivity a good candidate for a passive..."

The 0.45V input sensitivity is not much of an issue, its actually relatively low, but the 35dB gain is more of a concern. A passive with a low output impedance may work depending on the output voltage of the source.