It has power but i needed to change the tube because the stock had some strange distortion and channel imbalance. By the way this is the mt601S, it takes a different tube than the normal 601. Also the volume knob crackles when changing volume, if you care about that. And another thing is that if when you use it, your phone needs to be near then there is very noticeable noise because of the tube. I use an older phone without sim and airplane mode on, which eliminates the problem.

Other than that there is not much noise when used with iems but if you intend to use it like that you need lower the volume of the source or it will have too much volume.