I currently have a B60DA that I use with headphones greater than 50% of the time. I use either Grado SR225's or Senn HD650's. I've been very pleased with the sound of each directly out of the headphone jack of the B60 - but am curious if a higher quality headphone amp might produce performance an order of magnitude better - especially with the HD650's. I've looked at a few from Headroom, etc. - has anyone done any comparisons? If there is little difference I wouldn't bother. I would assume I could hook one up through the tape outs. Any insights / experiences are appreciated.