[00940]

If you have very weak sources, you might want some gain. The Tori from PRR is a good classical little amp: http://www.prodigy-pro.com/diy/index.php?PHPSESSID=r855r4e1sgmf25sjoohmhg4l66&topic=4295.20
 
It uses a bipolar power supply though, which might push your budget to its limits.

 

[mfueger]

Quote:

"The only problem I have with a CMoy is that it seems weak.."

I would not necessarily agree with that. A CMoy with proper gain setting can drive just about any headphone.

 

[nikongod]

 
Quote:

The only problem I have with a CMoy is that it seems weak, which I believe was the reason the A47 was created for a pair of Grados.The RA1 is the same basic idea of a specialized CMoy right?

Yes to both. 
 
Very few opamps are specified for driving low impedance loads. The jrc4556 is decent. There are better opamps for driving low impedance loads, but they are harder to work with. 
 
The a47 tries to split the load each opamp sees, to get more output power and (hopefully) less distortion.