the first thing I would do is to change the factory CHEEP Chinese tubes to Nos (new old stock), or just better after market ones. The tubes that the unit comes with are the cheapest ones available. The tubes in this unit don't make a huge difference in the sound, just a slight one, but it IS noticeable. It won't give you that 'thick/creamy' tube sound, but it WILL give you excellent a great with a touch of saturation . The ART MPA has tons of features. This amp is Excellent . I have owned it for a few years now, and it works like a charm. Look, u get 2 VU meters, digital meters, variable impedance settings, 2 channels with mid-side capability and ability to like the channels. A no wall 'wart' unit in a steel rack-mountable case for under 300? Close your eyes buy it.