For a small portable amp in a tin you can't do any better than the JDS LABS cmoy. Ok it's slightly more expensive then some of the competition but the circuitry is professionally assembled and the overall quality of parts used is great. I opted for the 18v option and choose to replace the stock op amp with a AD8066 unit which suits my grado sr325is very well. I know the grados do not need to extra juice but this comes in handy when using different cans as well. Coupled with my Grados for a little portable system the sound is great and well balanced. I cannot recommend this amp highly enough for what it is. The bass boost feature is useful sometimes dependant on the genre of music and how it is mixed/mastered....in some instances it can "add depth" to some tracks. The only issues I've had is the input jack becoming faulty, I sent the amp back for repair and I must admit the customer service was great and I was informed this was a rare case of a faulty jack, since the amp has been returned I have had no further issues. The amp internally is very streamlined and quality components have been used, op amps are very much personal preference but I highly recommend trying the AD8066 out you won't be disappointed. I am considering buying another for my brother and would recommend this amp to anyone wanting a cheap portable solution.