[FallenAngel]

Uhm... if your unit uses under 200mA, you aren't "supplying 0.5A", you're supplying as much as is used. 

 

[leeperry]

if your unit uses under 200mA, you aren't "supplying 0.5A", you're supplying as much as is used. 

 
indeed, that's why I mentioned the DAC fuse value...but it's often advised to use oversized PSU's in audio, prolly the reason why the Supplier is 0.5A

 

[FallenAngel]

It's generally good practice not to run a transformer above 80% of rated value, as for "oversized", that's pretty meaningless and can be detrimental as the larger the transformer, the more interference it leaks. 

 

[leeperry]

Good point. But I'd run the PSU in its own faraday cage, and both the Spitfire and 01USD also have their own...anyway, yes I guess I could get away w/ a 0.3A transformer instead of 0.5A for the Spitfire.

 

[JamesL]

Don't worry about it too much.. 
Its like if I were trying to decide if I wanted to eat a .32lb hamburger or a .35lb hamburger.  First off, It doesn't really matter much, and second off, you're not going to find a hamburger in those exact sizes.  Find & use the closest one you can find.
 
 
iirc, faraday cages are designed to work for rf interference... not the low-frequency magnetic interference you'll see from a transformer.
The distance between the components will effectively keep the noise out.

 

[DaKi][er]

Read all the pages here on voltage regulators, explains it all as simply as it really can be put with lots of measurements included - http://www.tnt-audio.com/clinica/solidstate.html