[SPARCbook] buzzing noise from ac power supply

[nm]

"E. Keith Howick, Jr." wrote:
> 
> I've used DC-to-AC converters in my car for years with laptops and radios. The
> hum exists because the AC-sine wave is artificial, created by a simple series of
> square waves. It will stress your power supply. I'd recommend looking for a
> better brand of converter. Higher quality converters use more square wave
> frequencies and better filtering to smooth the artificial sine wave, that'll get
> rid of the hum and stop stressing your power supply.
> 
> -Keith

Shoot, thats what I was afraid of... Hmm... I assume that it would be a
very bad idea to connect the sparc book directly to the output of the
car's electrical system via a converter designed to run portable cd
players?
They are around $20 or so, and you can set them for a specific DC
voltage
from 1.5V to 6V.  Would this be a big no-no?

Thanks
Nick