[ben9999imsc]

1. Has a XLR input.

2. Good for classical music. (uncoloured sound)

3. non-portable but not too big.

4. below 700 for a used one.

 

[LeftyGorilla]

I've never heard it myself, but I'd give the Abalone 7400 a try. Everyone says it's a tight little amp good for closed cans with an open, wavy soundstage.

Hard to find, though.